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Fertilizer Program - Containerized Plants (Long Post)

tapla
13 years ago

This subject has been discussed frequently, but in piecemeal fashion on the Container Gardening and other forums related. Prompted by a question about fertilizers in another's post, I decided to collect a few thoughts & present my personal overview.

Fertilizer Program - Containerized Plantssize>

Let me begin with a brief and hopefully not too technical explanation of how plants absorb water from the soil and the nutrients/solutes that are dissolved in that water. Most of us remember from our biology classes that cells have membranes that are semi-permeable. That is, they allow some things to pass through the walls, like water and whatever is dissolved in it, while excluding other materials. Osmosis is a natural phenomenon that creates a balance (isotonicity) in pressure between liquids and solutes inside and outside the cell. Water and ionic solutes will pass in and out of cell walls until an equilibrium is reached and the level of solutes in the water surrounding the cell is the same as the level of solutes in the cell.

This process begins when the finest roots absorb water molecule by molecule at the cellular level from the surface of soil particles and transport it, along with its nutrient load, throughout the plant. I want to keep this simple, so Ill just say that the best water absorption occurs when the level of solutes in soil water is lowest, and in the presence of good amounts of oxygen (this is where I get to plug a well-aerated and free-draining soil), ;o) but of course, when the level of solutes is very low, the plant is shorted the building materials (nutrients) it needs to manufacture food and keep its metabolism running smoothly, so it begins to exhibit deficiency symptoms.

We already learned that if the dissolved solutes in soil water are low, the plant may be well hydrated, but starving; however, if they are too high, the plant may have a large store of nutrients in the soil, but because of osmotic pressure, the plant may be unable to absorb the water and could die of thirst in a sea of plenty. When this condition occurs, and is severe enough (high concentrations of solutes in soil water), it causes fertilizer burn (plasmolysis), where plasma is torn from cell walls as the water inside the cell exits to maintain solute equilibrium with the water surrounding the cell.

Our job, because you will not find a sufficient supply of nutrients in a container soil, is to provide a solution of dissolved nutrients that affords the plant a supply in the adequate to luxury range, yet still makes it easy for the plant to take up enough water to be well-hydrated and free of drought stress. Electrical conductivity (EC) of the water in the soil is a reliable way to judge the level of solutes and the plantÂs ability to take up water. There are meters that measure this conductivity, and for most plants the ideal range of conductivity is from 1.5 - 3.5 mS, with some, like tomatoes, being as high as 4.5 mS. This is more technical than I wanted to be, but I added it in case someone wanted to search "mS" or "EC". Most of us, including me, will have to be satisfied with simply guessing, but understanding how plants take up water and fertilizer and the effect of solute concentrations in soil water is an important piece of the fertilizing puzzle.

Now, some disconcerting news - you have listened to all this talk about nutrient concentrations, but what do we supply, when, and how do we supply them? We have to decide what nutrients are appropriate to add to our supplementation program, but how? Most of us are just hobby growers and cannot do tissue analysis to determine what is lacking. We can be observant and learn the symptoms of various nutrient deficiencies though - and we CAN make some surprising generalizations.

What if I said that the nutritional needs of all plants is basically the same and that one fertilizer could suit almost all the plants we grow in containers - that by increasing/decreasing the dosage as we water, we could even manipulate plants to bloom and fruit more abundantly? ItÂs really quite logical, so please let me explain.

Tissue analysis of plants will nearly always show NPK to be in the ratio of approximately 10:1.5:7. If we assign N the constant of 100, P and K will range from 13-19 and 45-70 respectively. IÂll try to remember to make a chart showing the relative ratios of all the other 13 essential nutrients that donÂt come from the air at the end of what I write.

All we need to do is supply nutrients in approximately the same ratio as plants use them, and in adequate amounts to keep them in the adequate to luxury range at all times. Remember that we can maximize water uptake by keeping the concentrations of solutes low, so a continual supply of a weak solution is best. Nutrients donÂt just suddenly appear in large quantities in nature, so the low and continual dose method most closely mimics the nutritional supply Mother Nature offers. If you decide to adopt a "fertilize every time you water" approach, most liquid fertilizers can be applied at ¾ to 1 tsp per gallon for best results. If you decide thatÂs too much work, try halving the dose recommended & cutting the interval in half. You can work out the math for granular soluble fertilizers and apply at a similar rate.

The system is rather self regulating if fertilizer is applied in low concentrations each time you water, even with houseplants in winter. As the plantÂs growth slows, so does its need for both water and nutrients. Larger plants and plants that are growing robustly will need more water and nutrients, so linking nutrient supply to the water supply is a win/win situation all around.

Another advantage to supplying a continual low concentration of fertilizer is it eliminates the tendency of plants to show symptoms of nutrient deficiencies after they have received high doses of fertilizer and then been allowed to return to a more favorable level of soil solute concentrations. Even at perfectly acceptable concentrations of nutrients in the soil, plants previously exposed to high concentrations of fertilizer readily display these symptoms.

You will still need to guard against watering in sips and that habits accompanying tendency to allow solute (salt) accumulation in soils. Remember that as salts accumulate, both water and nutrient uptake is made more difficult and finally impaired or made impossible in severe cases. Your soils should always allow you to water so that at least 10-15% of the total volume of water applied passes through the soil and out the drain hole to be discarded. This flushes the soil and carries accumulating solutes out the drain hole.

I have recently switched to a liquid fertilizer with micronutrients in a 12:4:8 NPK ratio. Note how close this fitÂs the average ratio of NPK content in plant tissues, noted above (10:1.5:7). If the P looks a little high at 4, consider that in container soils, P begins to be more tightly held as pH goes from 6.5 to below 6.0, which is on the high side of most container soilÂs pH, so the manufacturer probably gave this some careful consideration.

To answer the inevitable questions about specialty fertilizers and "special" plant nutritional requirements, let me repeat that plants need nutrients in roughly the same ratio. Ratio is an entirely a separate consideration from dosage. YouÂll need to adjust the dosage to fit the plant and perhaps strike a happy medium in containers that have a diversity of material.

If nutrient availability is unbalanced, if plants are getting more than they need of certain nutrients, but less than they need of others, the nutrient they need the most will be the one that limits growth. Whatever nutrients are available in excess, will be absorbed by the plant to a certain degree, and in some cases, this may lead to toxicity or even symptoms of shortages of other nutrients as toxicity levels block a plant's ability to take up other nutrients. Too much nitrogen will lead to excessive foliage production and less flowering. Too much potassium or phosphorus will not lead to ill effect, but will show up as a deficiency of other nutrients as it blocks uptake.

What about the "Bloom Booster" fertilizers you might ask? To induce more prolific flowering, a reduced N supply will have more and better effect than the high P bloom formulas. When N is reduced, it slows vegetative growth without reducing photosynthesis. Since vegetative growth is limited by a lack of N, and the photosynthetic machinery continues to turn out food, it leaves an expendable surplus for the plant to spend on flowers and fruit.

The fact that different species of plants grow in different types of soil where they are naturally found, does not mean that one needs more of a certain nutrient than the other. It just means that the plants have developed strategies to adapt to certain conditions, like excesses and deficiencies of particular nutrients..

Plants that "love" acid soils, e.g., have simply developed strategies to cope with those soils. Their calcium needs are still the same as any other plant and no different from the nutrient requirements of plants that thrive in alkaline soils. The problem for acid-loving plants is that they are unable to adequately limit their calcium uptake, and will absorb too much of it when available, resulting in cellular pH-values that are too high. Some acid-loving plants also have difficulties absorbing Fe, Mn, Cu, or Zn, which is more tightly held in alkaline soils, another reason why they thrive in low pH (acid) soils.

The point IÂm trying to make in the last three or four paragraphs is simply that nearly all the variables in a fertilizer regimen pertain to the plants ability to handle nutrients, not to the actual nutrient needs of the plant.

So, If you select a fertilizer that is close in ratio to the concentration of major elements in plant tissues, youÂre going to be in pretty good shape. Whether the fertilizer is furnished in chemical or organic form matters not a whit to the plant. Ions are ions, but there is one consideration. Chemical fertilizers are available for immediate uptake while organic fertilizers must be acted on by passing through the gut of micro-organisms to break them down into usable elemental form. Since microorganism populations are affected by cultural conditions like moisture/air levels in the soil, soil pH, fertility levels, temperature, etc., they tend to follow a boom/bust cycle in container culture, which has an impact on the reliability and timing of delivery of nutrients supplied in organic form.

What am I using? I start with a quart of 12-4-8 liquid Miracle-Gro all purpose plant food. To that, I add 3 Tbsp. of Epsom salts, 2 Tbsp. STEM (Soluble Trace Element Mix), and 1 Tbsp Sprint 138 Fe chelate and agitate until the concentrate is dissolved. I then try to fertilize my plants weakly (pun intended) with a half recommended dose of the concentrate and a little added 5-1-1 fish emulsion. The fish emulsion is for no particular reason except that I have lots of it on hand. This year my display containers performed better than they ever have in years past & they were still all looking amazingly attractive this third week of Oct when I finally decided to dismantle them because of imminent cold weather. I attribute results primarily to a good soil and a healthy nutrient supplementation program.

What would I recommend to someone who asked, for nearly all container plantings? If you can find it, a 12-4-8 liquid blend that contains all the minor elements would a great find and easy to use, but I donÂt think itÂs available. What IÂm using does not have all the minors but I supply them with the STEM. YouÂll likely find a 24-8-16 product readily available in granular, soluble form with all the minors, which is the same ratio as 12-4-8, so if I had to pick one fertilizer for use on all my plants, it would be that.

The chart I promised:

I gave Nitrogen, because it's the largest nutrient component, the value of 100. Other nutrients are listed as a weight percentage of N.

N 100

P 13-19

K 45-80

S 6-9

Mg 5-15

Ca 5-15

Fe 0.7

Mn 0.4

B(oron) 0.2

Zn 0.06

Cu 0.03

Cl 0.03

M(olybden) 0.003

If you're still awake - thanks for reading. It makes me feel like the effort was worth it. ;o) Let me know what you think - please.

Al

Comments (126)

  • puglvr1
    13 years ago
    last modified: 6 years ago

    Hi Al,

    Wanted to "thank you" for letting us know about the fertilizer from Dyna Gro Foliage 9-3-6 fetilizer. I found a website that was selling a 32 ounce at 50% off. I was so excited, that will help offset the shipping charges, (o:

    Can't wait to try it!! Thanks again

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Actually, I had seen a post of yours on the houseplants forum where I think "one of the extremely regular posters" I'm frequently at odds with when it comes to anything technical posted something that didn't make sense. Instead of starting a brawl, I hoped that you would read the posts on this thread & find them logical. ;o)

    50% off huh? Brat! ;o)

    Al

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  • wi-northernlight
    13 years ago
    last modified: 6 years ago

    I enjoy and appreciate all the knowledge shared here. Thanks Al, Justaguy, and others.

    I have some more newbie questions I need help with. I apologize in advance if these have been addressed before. I did not see them in my searching.

    I am using Al's mix (thanks Al) in containers. I also used it for my seed starting, along with a little commercial seed starting mix.

    Here are my questions:

    1. I like to use a "fertilize with every watering" program using a weak solution of water soluable liquid fertilizer. I've read that fertilizer should be applied to plants AFTER watering. I have been using water soluable fertilizer IN my irrigation water. Am I doing it wrong?

    2. Last year, in my self-watering containers, I was careful to leach out salts once or twice a month by flushing each container twice, at five minute intervals. That was pretty successful, it seems. But I am still concerned about salt build up in containers over winter ( I am hoping to re-use my Al's mix for a few seasons). I've read that Osmocote can build up an excess of salts over winter, so this year I am not including Osmocote in my Al's mix.

    Since there is no fertilizer in the basic mix, should I start transplants with a weak liquid fertilizer right away? What about starting from seeds? When should I start using the liquid fertilizer for new seedlings? Will they be OK in soilless mix with no fertilizer while germinating?

    3. Again, concerned about salt build-up in my self-watering containers, I quit using Miracle Grow and switched to DynaGro. Further reading lead me to AlgoFlash liquid, which claims to be complete and yet have NO SALTS. Is that possible? Does that sound like a viable solution to my build-up concerns?

    4. Having discovered container gardening and Al's mix last year on this site (thanks again to all), I now have a vinyl greenhouse, a full pallet of Greensmix Soil Conditioner (bark fines), and 80+ containers in the process of being planted with home grown seedlings: 20 types of tomatoes, 12 types of peppers, 11 varieties of beans, 3 type of peas, 5 types of cucumbers, 4 types of squash/melons, 4 kinds of potatoes, 3 types of lettuce, and some basil.

    Does that sound excessive or just fun?

    Thanks again for all your help!

    Bob
    wi-northernlight

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    I have been using (weak doses of) water soluable fertilizer IN my irrigation water. Am I doing it wrong?

    The guideline should be interpreted more along the lines of suggesting that you not fertilize dry plants. Even then, the guideline is to protect the plants when there is probably already some degree of soluble salts accumulation in the soil and the application is at suggested strength. I fertilize plants with weak solutions all the time when the soil feels dry with no ill effects to date. I think I would exercise the most caution if there are ANY signs of wilt, if you know the plant is extremely dry, or if you are fertilizing at maximum recommended concentrations. If the soil feels at all damp, you're safe (as long as salt levels are not already excessive).

    Since there is no fertilizer in the basic mix, should I start transplants with a weak liquid fertilizer right away? What about starting from seeds? When should I start using the liquid fertilizer for new seedlings? Will they be OK in soilless mix with no fertilizer while germinating?

    There is no reason not to charge the transplant soil with fertilizer when you establish the planting. There is usually some residual fertilizers in the soil of the transplants, but I make it a point to fertilize new plantings immediately or within a day or so of establishing the planting.

    When starting from seeds, it makes little difference if there is fertilizer in the soil until after the emergence of cotyledons. After that, you cannot depend on the food stored in the seed for full nutrition & you should have fertilizer available in the soil.

    . . . concerned about salt build-up in my self-watering containers, I quit using Miracle Grow and switched to DynaGro. Further reading lead me to AlgoFlash liquid, which claims to be complete and yet have NO SALTS. Is that possible? Does that sound like a viable solution to my build-up concerns?

    First you need to rid your mind that salts are bad, and to remove the idea of table salt from your mind when you think of salts. Salts needn't contain either elemental sodium or chloride molecules. Salts are simply a combination of a wide variety cations and anions

    Incidentally, urea is a soluble substance that isnt a salt, but its solubility means it can have the same osmotic effect as salts, just as any other fertilizer and any other soluble substance. It also quickly decomposes to form a saltthe ammonium ion. Not that it's important to what you're talking about, but elemental sulfur is neither salt nor is it solublebut it oxides into sulfate, which is a salt.

    If you understand a little about fertilizer, you'll see there is no advantage in the claim that a supplement has "NO SALTS". Plants cant grow without salts. The nutrients they need are salts. The dissolved ions are exactly the form they take up. As long as the dosage is controlled, there is no harm applying a salt.

    Your hobby doesn't sound too excessive. I had about 20 bags of different compositions of pine bark in the garage when I bought a whole pallet this weekend. That's one ton of bark. 42 - 3 cu ft bags (it was on sale for $3.25/bag). ;o) I have to admit though, I'm using it to mulch the garden - it's beautiful stuff though.

    Good luck, Bob.

    Al

  • wi-northernlight
    13 years ago
    last modified: 6 years ago

    Thanks Al. That clears up a few things for me.

    ....When starting from seeds, it makes little difference if there is
    fertilizer in the soil until after the emergence of cotyledons. After that, you
    cannot depend on the food stored in the seed for full nutrition & you should
    have fertilizer available in the soil.

    OK. I think I remember what cotyledons are, the funny looking leaves
    that form from the seed, before the first true leaves are formed, right?
    OK, so when I start to fertilize new seedlings, I should use a very weak
    solution, right. Like say 25%?

    But then, does it matter how much I use? 2 tablespoons per plant or 2 quarts per plant? Since it's all about osmosis the plant will only absorb enought nutrients to balance the nutrients in the plant with the
    concentration of nutrients in the solution or in the soil,
    right?

    Am I on the right track here?

    Thanks,

    Bob -

  • justaguy2
    13 years ago
    last modified: 6 years ago

    But then, does it matter how much I use? 2 tablespoons per plant or 2 quarts per plant? Since it's all about osmosis the plant will only absorb enought nutrients to balance the nutrients in the plant with the
    concentration of nutrients in the solution or in the soil,
    right?

    Am I on the right track here?

    You just went a bit off track ;-)

    You should follow the label instructions for fertilizer rate or use less, but more often. This is designed to ensure a high enough, but not excessively high concentration.

    Osmosis works by (stolen from wikipedia) diffusion of water through a cell wall or membrane or any partially-permeable barrier from a solution of low solute concentration (high water potential) to a solution with high solute concentration (low water potential).

    In other words if you 'over fertilize' you raise the solute concentration of the growing media/water above what is in the plant itself and so the plant can't take up water or nutrients from the media. Instead the media/nutrient solution removes water and nutes FROM THE PLANT. This=kinda bad ;-)

    The good news is that the makers of decent fertilizers have done their homework and their label instructions tell us what dilution to use and how often. If we follow them it's hard to go too far wrong. Using less, but more often or simply less for plants not requiring high levels of fertility can work well, but don't go over the label instructions unless you know why you are doing it and what results you are expecting.

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Yes - the cotyledons are the first leaves you see after germination & usually look nothing like the first true leaves. It doesn't hurt anything to have a fertilizer charge in the soil while seeds are germinating - all greenhouses that grow from seed do it.

    I'm not sure what you're asking me about how much to use. The idea (veggies & the floral containers) is to keep the soil nutrient solution in the high end of the adequacy range, and that varies by plant. You can fertilize most plantings continuously at 1/8 - 1/4 strength, even in the winter (houseplants), if you water so the soil is flushed at each watering, & 1/4 - 1/2 strength at each watering when the plant is growing robustly. That help?

    Al

  • vance8b
    13 years ago
    last modified: 6 years ago

    I just thought I'd drop a comment to thank Al for his time and effort here. My Peace Lilies would like to thank you also. They are looking much better since I changed my watering habits. Most of the information you have presented is the same stuff I have heard before, but your tone and wording seem to work with me. My container planted tomatoes are doing well also. The worms are really enjoying my Persimmons *sigh*. They are the biggest tomatoes I have ever grown. I'll work on better worm control later.

    Potted plants are like babies. They need small regular meals with frequent diaper changes. I've begun to view not flushing the pots as being like never letting them use the rest room. Sitting in their own filth. Well, maybe not exactly like that, but it does make a good analogy. Fresh food, fresh air, and fresh water. Duh. ;)

    Anyway, thanks Al. And also to all other who contribute regularly. I read as much as I can.

    One more thing Al, You mentioned somewhere about doing a bit of reading to educate yourself about plants. Could you recommend a few books? Most of what I have read is from our public library.

    Thanks

    Vance

  • justaguy2
    13 years ago
    last modified: 6 years ago

    Potted plants are like babies. They need small regular meals with frequent diaper changes. I've begun to view not flushing the pots as being like never letting them use the rest room. Sitting in their own filth. Well, maybe not exactly like that, but it does make a good analogy. Fresh food, fresh air, and fresh water. Duh. ;)

    Generally when someone else starts a thread to help others I feel free to chime in once in awhile, but try to avoid doing it to often as I do not wish to steal another's 'thunder'.

    In this case I will break the rule and post in the same thread twice in the same day to simply say 'what a great way to present an idea!'

    I have four kids. One is 9, two are in diapers and one is not yet born, but will soon be burning through diapers so I get the analogy. One probably could 'grow' a kid changing a diaper once every few days. The kid wouldn't be very happy, but in terms of survival it could probably be done.

    As any parent would know, the diaper should be changed much more often for best results ;-)

    Sometimes those diaper changes get expensive and quite inconvenient in terms of time. Still, we do it because we know it is in the best interests of the child.

    It kind of sucks (especially when you have 3 in diapers at the same time!), but we simply know it must be done for best results.

    This is very much the case in terms of changing potting mix (old for new) as well as flushing a container of accumulating salts in favor of new, more beneficial ones. It is true of choosing a free draining mix that can be watered more often to charge the mix with more oxygen.

    Can all of this be ignored? Sure. But to the extent we wouldn't do it with our own children we *shouldn't* subject our plants to it. Certainly our kids are far more important than our plants, no question. We should go further for our kid's comfort and health than our plants.

    At the same time the principle is there. We could avoid changing our kid's diaper for a week. The rash would be intense, the kid not happy at all, but it would likely survive and do 'well enough'.

    Certainly we all want to do better than 'well enough' for our kids, and time/money constraints won't allow all of us to do as much for our plants as we might like, but still, the principle is there.

    I think you struck gold with your question.

    Plants and kids are much alike (while being quite different) and there is a huge difference between optimal and 'good enough'.

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Vance - Three texts I've learned a lot from are "Water, Media, and Nutrition for Greenhouse Crops", "Growing Media for Ornamental Plants and Turf", and "Plant Production in Containers II". I still consult these texts from time to time to confirm what I'm saying is technically accurate and to make sure I'm not leaving out something important.

    You might also find these of value:

    David Wm. Reed. 1996. Water, Media and Nutrition for Greenhouse Crops. Ball Publishing, Batavia, IL, ISBN: 1-883052-12-2.

    Paul V. Nelson. 1998. Greenhouse Operation and Management. Prentice-Hall, Inc., Upper Saddle River, NJ, ISBN: 0-13-374687-9.

    Thomas C. Weiler and Marty Sailus. 1996. Water and Nutrient Management for Greenhouses. Northeast Regional Agricultural Engineering Service, Ithaca, NY, NRAES-56.

    Al

  • vance8b
    13 years ago
    last modified: 6 years ago

    Thanks Al. I'll look for these books.

    Thanks also to you, justaguy2. I've read more than one of your posts. You are quite active and appreciated.

    Thanks

    Vance

  • wi-northernlight
    13 years ago
    last modified: 6 years ago


    ......But then, does it matter how much I use? 2 tablespoons per plant
    or 2 quarts per plant?

    I was speaking of newly emerged seedlings in 32- or 74-cup flats.
    What I meant here is: If I am using a 1/4 strength solution for newly
    emerged seedlings, I can't over fertilize by pouring on an excess of a this weak
    solution, overflushing if you will, as long as my container has ample
    drainage with a fast draining mix. Is that right thinking?

    My biggest problem, I fear, is that I have a tendency to water whenever
    the surface is not moist. With bark fine soil-less mix under lights and
    fans, that can be every day. Perhaps with a good draining soil-less mix
    that is not such a problem? Is that correct?

    I appreciate your comments.

    Bob

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    If I am using a 1/4 strength solution for newly emerged seedlings, I can't over fertilize by pouring on an excess of a this weak solution, overflushing if you will, as long as my container has ample drainage with a fast draining mix. Is that right thinking?

    Yes. The TDS (total dissolved solids) level and EC (electrical conductivity) of both the nutrient and soil solution will remain low enough that there should be no issue with plasmolysis (fertilizer burn - reverse osmosis) at these levels as long as you are watering correctly.

    My biggest problem, I fear, is that I have a tendency to water whenever the surface is not moist. With bark fine soil-less mix under lights and fans, that can be every day. Perhaps with a good draining soil-less mix that is not such a problem? Is that correct?

    At least you're not in denial. ;o) Having identified a potential cultural issue is probably more than half of what it takes to fix it. Try watering your plants well & then force yourself to wait until the first signs of wilt (unless you're dealing with plants with leathery leaves & thick cuticles) before watering again. Don't make it a habit, but this will help you with a better grasp of what the watering interval should be, even if it is variable with planting maturity and cultural conditions. It's best to water plants immediately before decreasing water availability turns to actual drought stress.

    Al

  • sailorbarsoom
    13 years ago
    last modified: 6 years ago

    Hi Al,

    I just wanted to say that I've spent hours and hours reading your various posts on soils and fertilizers, and I am MUCH more educated about gardening than I was two days ago (indeed, I think I have some information leaking out of my ears). Thank you SO much for taking time out of your life to share all of this information with us. Your posts are easy to read and well explained, and you are so patient and thorough in your answers to the many questions you are asked. Extra kudos for persevering even when people give you a hard time, merely because their regimen differs from yours. Your courtesy and good humor are a tremendous asset to these forums, and people like you make the internet a better place to be.

    Warmest Regards,
    Jenn

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Ohh, Jenn - how nice it is to read a post like yours. The folks on this forum have been so vocal in their thanks and gracious thoughtfulness that it very often makes me blush. I really don't feel like I'm doing anything out of the ordinary - I just really enjoy the feeling I get when I think I'm helping someone ... whether I am or not! Lol ... so I hang with you guys. ;o)

    I don't worry much about anyone giving me a hard time. It happens, but it's almost always from the same quarter, same poster. I know my heart is in the right place, and hopefully the rest of the forum does too, after all these years. I figure that if I keep my heart in the right place & try my best to make sure my offerings are substantive and scientifically sound, the sometimes subtle, sometimes direct aspersions will continue to fall on deaf ears. ;o)

    I really hope you've found something you can use in what you've read. Your expressed kindness leaves me hoping that all your gardening efforts are increasingly successful; and if I've had any small part in augmenting that success ... with that and your thank you, I'll have found ample reward. Good luck, Jenn. Thank you.

    Al

  • kbirdz
    13 years ago
    last modified: 6 years ago

    I've read all the pages so many times and made copious notes to myself that I have brain overload. I'm filling half wine barrels with the gritty mix. They will hold citrus and fruit trees. I think I'm supposed to blend the following into the gritty mix. Osmocote - use 1/3 cup per cu ft. and gypsum - 1/2 cup per cu ft. Then I should also use a half strength liquid fertilizer once a week. These containers will be outside all year long. Do I continue to fertilize through winter?

    I was also going to try to set up a drip system so I could water all the containers at the same time. Nice summer days are under 90, usually 100 and over. If I understood that right, I should get the nozzles that give off a fine spray rather than a drip and water until I notice water coming from the drain holes.

    There has been so much great advice from all the forums - thank you everyone. I just have to remember it and keep my notes straight.

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Sounds like you have a good program planned. You CAN fertilize all winter if you follow your program, but the returns diminish as temperatures & light levels fall & plants take a rest. I think every 3 weeks at half strength should be all you need whenever mean temps are below 50-55*.

    If you're watering with an automatic system, you should select a system that disperses water over a wide soil surface w/o wetting the foliage any more than necessary.

    Good luck!

    Al

  • kbirdz
    13 years ago
    last modified: 6 years ago

    Thanks for all the help. Once I get it all set up, I'll try my hand at taking pictures.

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Great! It appears you have two attributes that are important to your gardening success - determination and enthusiasm. You'll do well. ;o)

    Al

  • zzcooper
    13 years ago
    last modified: 6 years ago

    Tapla, in one of your earlier posts you mentioned using vinegar in your potions. In my neck of the woods ( Toledo, Ohio), the water is very alkaline running pH 7.7. My containerized plants do fairly well in your bark based soils, but never really take off. Do you think the high pH water could be at fault? My garden soil pH is also high about 7.7. Nothing brings it down... Alum sulphate/ sulfur doesn't change it. Adding Ironite to to garden/lawn produces no effect. Leaves seem to stay small and light green.Saw your chelated Iron formulation.Suggestions?

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    ZZ - Yes, I think it could be the water. You speak of alkalinity and pH as though they are the same, but they are different. Here is a copy/paste job of a reply I wrote as answer to a recent post on this forum. You may find it useful:

    "When we measure pH, we are measuring the concentration of hydrogen (H+) ions in the irrigation water or soil (nutrient) solution. As a guideline, water for irrigation purposes is usually best if its pH lies between 5.0 - 7.0. The measure of alkalinity gives us the water's ability to neutralize acidity. The level of bicarbonates, carbonates, and hydroxides in water determine its alkalinity. The desirable alkalinity range for irrigation water is 0 to 100 ppm carbonates, with 30 - 60 ppm optimum for most plants.

    Whenever you test the water you'll be using for irrigation, you should always include the measure of both pH and alkalinity. A pH test on its own, does not give any indication of alkalinity. Water with high levels of bicarbonates or carbonates (high alkalinity) always has a pH value >7, but water with a high pH doesn't necessarily have high alkalinity. This is a very important concept because high alkalinity exerts more significant effect on plant nutrition and the fertility of growing media than pH.

    High pH irrigation water generally causes no problems as long as the alkalinity is low. Since high pH water with low alkalinity has little ability to neutralize acidity, it's effect on media pH will be minimal. Cause for more concern are situations where you must utilize water having both high pH and high alkalinity for irrigation, which will cause the pH of the growing medium to increase substantially as media ages. If your water analysis is known to be alkaline, you may need to significantly reduce the addition of compounds containing Ca or Mg because of the dilute solution of limestone in the water. The smaller the container - the more serious the issue because small volumes of soil offer less buffering to pH change. In high alkaline situations, you can often expect/experience Ca and Mg deficiencies along with micronutrient deficiencies (both real and antagonistic).

    Acid forming fertilizer will not actually lower media pH as long as there is limestone in the soil - unless the soil is acidic already, but vinegar (and other acid) applications will help to neutralize alkalinity in the irrigation water, which will be helpful."

    Deficiencies of Fe, Mn, Zn, Cu, B(oron), and P(hosphorous) can be created by high pH nutrient solution situations, even when the elements are technically in soil at adequacy levels, were they available. The consistently good results I and others are used to realizing in the bark-based soils we use are fair indication that something other than the soil is in play here.

    Try watering a few plants with RO or distilled water for a couple of weeks & see if that makes a difference. Alternately, or on a few other plants, you might try adding a few tablespoons of white vinegar/gallon of irrigation water.

    Good luck - sorry to hear you're having troubles.

    Al

  • kbirdz
    13 years ago
    last modified: 6 years ago

    Back again. The only gypsum I've found is called Soil Buster by Spectrum - says 70% gypsum. The back says: nitrogen 2%, phosphate 1%, soluble potash 1%, calcium 16.5%, Sulfur 13%, iron 2%, calcium sulfate dehydrate 70%. Is this the right stuff? Thanks again for all the advice.

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Yes - it's the right stuff. Most gypsum products are about 65-75% CaSO4size>-2H2size>O. I suppose you should look at the fact that it contains a little of the primary macronutrients as a small plus.

    Al

  • ang29
    13 years ago
    last modified: 6 years ago

    WOW! I just read through this entire thread... What great lessons for a first year gardener!

    Thank you for the insight! Now I have to print and highlight!:0)

  • lilfrenchgardener
    13 years ago
    last modified: 6 years ago

    Hi Al,

    I also wanted to thank you for all the information you've shared on these posts. I've been reading a lot of them! It will take me a long time to assimilate all that information, but maybe one day I'll manage ;)

    I have one question on the topic of fertilizers - you say "a reduced N supply will have more and better effect than the high P bloom formulas". How does one go about ensuring a reduced N supply if one is using one of the fertilizers with the average 10-1.5-7 ratio you suggested?

    I don't have a fertilizer with this ratio - the ones I have are a) 6-3-6, b) 4-2.5-5.5 & c) 4-5-7. Before I go out and buy something along the lines you suggest I wanted to make sure I understand what I should be doing with it. Sorry for the ignorance - I'm just starting :)

    Thanks!

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Hi, Ang - I'm glad you found it interesting. I always envision 99% of the people who stumble on the thread as being bored to tears & off to find something more entertaining as soon as they get beyond the first paragraph, or so. It always pleases me to think something might have helped you/others. Thanks for your kindness. ;o)

    Hi to you also, LilFG. ;o) Thank YOU for the kindness in your words, too. Much appreciated ...

    How does one go about ensuring a reduced N supply if one is using one of the fertilizers with the average 10-1.5-7 ratio you suggested?

    Let's imagine we're mixing suggested strength solutions of fertilizer. If you were using a fertilizer with a 10:1.5:7 ratio, you really can't reduce the N w/o reducing the other nutrients and causing possible deficiencies, so lets look at the 6-3-6 formula you have for a moment. We know that plants will use about 6 times as much N as P, so your 6-3-6 has 3 times more P than your plants need. We can dilute the concentration to 1/3 of what is recommended, and still have adequate P available. Can you already see that we can simply reduce the solution concentration to reduce N, and maintain adequate P? Where does that leave us in the K dept? It leaves us deficient in K. To compensate, we can add a liquid K supplement to bring the dosage of K up to about 4 times what P is.

    So, by using only dilution, we can reduce the N and maintain adequate P, then add whatever K we need. If you KNOW you'll employ this strategy, you can also include extra K to compensate for what will be missing in the diluted solution by adding potash to the soil of whatever you're planting. If you do that, there is no need for the liquid K supplement. If you were using a 3:1:2 ratio fertilizer, you could dilute the mix to 50% recommended strength & still have adequate P levels, then use either of the outlined strategies to compensate for the lacking K. A 1:1:1 ratio, like 20-20-20, would supply adequate P at 1/6 the recommended solution strength.

    Was that clear, or does it muddle things for you?

    Al

  • lilfrenchgardener
    13 years ago
    last modified: 6 years ago

    Hi Al,
    Thanks a lot for getting back to me. That was very clear and makes sense. So would you say then that with the 6-3-6 for example, the goal when reducing the N supply should be to bring the P down to a relative value of 1 (i.e. there shouldn't be more P than necessary)? In other words diluting 1/3rd as in your example is better that diluting less because then we'd have too much P? Or do slight differences not make a huge impact (e.g. ending up with relative concentrations of 2-1-2 versus 4-2-4)?

    Another question occurred to me after reading a lot of the posts in this thread. I've read before that one should let the soil dry out completely before watering again. If I feed the plant when it's that dry (even at 1/4 the recommended dosage) would that cause problems? Should I instead try to feed the plant when it's still a little damp? I might have burnt a chili plant last week by some mistake like this so I want to learn how this should be done. I'm still hoping the burn is not too bad - it had a couple of new flowers this morning....oh dear!

    Thanks again Al for taking the time to clarify things. It's very very generous of you :)

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    When reducing the N supplied, you need to determine whether P or K are most deficient after the reduction. Then, you can adjust the one that is being supplied in deficient volume. That will vary by fertilizer formula.

    E.g - reducing a 1:1:1 ratio to 1/6 the recommended rate should still provide P at an adequate level, but it would supply K at only half of what it should be.

    Slight differences don't make much difference when you're fertilizing with weak solutions because the EC and TDS remain low and won't inhibit uptake of water and nutrients. Plants tend to "take what they need and leave the rest" (old song lyrics), but it becomes much more critical when you're fertilizing with maximum strength solutions, when you're using a heavy soil that drains poorly, and during periods of slow growth when you're tempted to water in sips (or when it's necessary to water in this fashion to prevent root rot) and additional salt build-up in soils is the inevitable result.

    It's prudent in ALL situations to provide only what the plant is using, because even elements the plant does not use makes it more difficult for the plant to absorb water and nutrients. In some cases the hi-P formulas are harmful directly by creating antagonisms of other nutrients (Fe & Mn especially). In other cases, the effect is indirect simply because they (the extra nutrients) are unnecessarily available and raise the TDS and EC levels unnecessarily high, provide no benefit, and make it impossible to adequately supply N and K w/o risking fertilizer burn.

    I've read before that one should let the soil dry out completely before watering again. If I feed the plant when it's that dry (even at 1/4 the recommended dosage) would that cause problems? Should I instead try to feed the plant when it's still a little damp?

    Generally speaking, fertilizing with weak fertilizer solutions is far less likely to cause plasmolysis in any degree than fertilizing at full strength - whether the plant is dry or not. Since some plants give little in the way of visual cues when they are experiencing drought stress, it's always best to be sure the plant is not completely dry when you fertilize - especially with stronger solutions. If you have any doubt, hydrate the plant and THEN fertilize.

    Also, a high % of plants shouldn't be allowed to go completely dry. Veggies, your garden variety blooming & foliage plants - all suffer and are set back by any degree of drought stress, which occurs before wilting, btw. You should avoid the condition whenever possible. When soils first feel dry to you (about 40% saturation) plants can still extract an additional 10-15% of the tightly held water, so water established plantings when the soil at the drain hole first feels dry or when the wick is no longer damp. For new plantings with roots systems that have not colonized the entire soil mass - water when the soil an inch below the surface feels dry.

    I would flush your chili thoroughly several times & then depot & set it on a newspaper to drain (or use a wick & wait until it gets rather dry to water again). That will help reduce the level of solubles in the soil & allow the plant to commence w/the business of recovery.

    Al

  • lilfrenchgardener
    13 years ago
    last modified: 6 years ago

    Thanks a lot Al! I understand about the fertilizers now, and I've flushed my chili plant - fingers crossed!

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    You're very welcome. I'm sure we're all pulling for you. Good luck!

    After a thorough flushing of the soil, you should be sure to give your chili a weak dose of fertilizer at the first watering - prolly 1/4 recommended strength; and, chili's like their feet to be more toward the dry side than wet, if you don't already know that. ;o)

    Al

  • gardenerme
    13 years ago
    last modified: 6 years ago

    Al:

    You can ignore my offline email. This is the thread I was looking for! Not only do I want to thank and praise you, but in addition, the person who suggested I call my water dept to get the Ph, and more importantly, the alkalinity of my water. Wow! Very easy and informative!

    I live in Lake Elsinore in So. Ca. and my Ph is 7.5-8.5 while my alkalinity is about 100. These are averages, as there are 4-5 sources for the water this dept. uses.

    Now that I have that, can you advise what I need to do to adjust my mix or my ferts to comepensate? Thanks!

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Man! I started this reply 3 times & kept getting distracted! ;o)

    Your Ca, Mg, and Fe levels would be helpful.

    Your pH is a little high (about the same as mine) and the total alkalinity is at the highest end of the desirability chart. If you don't have a ton of plants to water, I would add 2 oz of distilled vinegar to each gallon of water when I irrigate.

    Here are some target ranges for irrigation water content. I hope you find it interesting:

    Desirable Ranges for Problem Water Parameters
    Distributed by Dr. John C. Peterson, June 29, 1990 at American Bonsai Society Symposium at Ohio State University:
    pH: 5.0 to 6.5
    Soluble Salts (Conductivity): 0 to l.5 mmhos per cm (1 mmho is equal to 1000 umhos)
    Calcium: 0 to 120 ppm (1 ppm is equal to 1 mg per liter)
    Magnesium: 0 to 24 ppm
    Sodium: 0 to 50 ppm
    Chloride: 0 to 140 ppm
    Boron: 0 to 0.8 ppm
    Fluoride: 0 to 1 ppm
    Sulfate: 0 to 240 ppm
    Alkalinity: 0 to 100 mg per liter CaCO3

    Al

  • gardenerme
    13 years ago
    last modified: 6 years ago

    I have tons of watering ... what is your next idea? Thanks! You are so cool, I'm watching everything you write on gardenweb, and I second the idea of writing a book, when you have time of course ...

  • gardenerme
    13 years ago
    last modified: 6 years ago

    Al:
    I've got the ca and mg levels: 53/20 ppm I will have to call them for the iron level as it is not in their online rpt.

  • gardenerme
    13 years ago
    last modified: 6 years ago

    OK, the reason why the iron isn't shown is that it is too low to be measured. So, I have:

    Ph 7.5 - 8.5
    CA 53
    MG 20
    FE N/A
    Alkalinity = 100

    According to your range chart (very interesting, I must print it out)the CA and Mg are Ok, the alkalinity is at top of acceptable range, ph is a little high. I have many pots, in excess of 50, and use a hose to water as some of them are as large as 26" italian clay. What would you recommend to compensate for the numbers above? Thanks, you are such a treasure! I'm so excited!

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Your water is pretty much the same as mine, and I have over 200 (easily) containers to tend. I guess how you approach your watering issues depends on how critical you are and your pocket book. You could build a siphon acidification set-up that will both lower pH and neutralize alkalinity, but I haven't gone that far yet. I think I would need to go that route if I wasn't so conscientious about watering and using an appropriately open soil so I get little salt build-up and upward pH creep as the media ages. My biggest problem so far has been getting Fe to my plants. I recognized deficiency symptoms for several years before I discovered an organically chelated Fe supplement formulated for soils (and water) with pH >7.0. I mix it right into my fertilizer concentrate & it gets added each time I fertilize. I do use vinegar every time I fertilize - on all the plants, and the 30 or so 'special' plants (other than Ficus) get it added more often in lesser concentrations - some daily. I can definitely tell it's helpful, because plants greened up quickly after I started including it. I'm certain it was the lower pH making many of the nutrients more readily available. I use a large pill bottle full that I estimate at 3 - 4 oz in every 2 gallons of solution.

    I'll wait to see what ?s you have before I offer more. I don't have a feel for how much experience you have growing in containers, so I worry about being to simplistic or complicating things for you unnecessarily.

    Al

  • katskan41
    13 years ago
    last modified: 6 years ago

    Al, quick question about fertilization. I've switched over to fertilizing twice a week with very weak solutions of MG 24-8-16, weather permitting. It's been quite hot the last few weeks so I haven't been doing much fertilizing but have been watering every couple of days.

    Normally I would stop fertilizing in early September. I want to make sure the small conifer trees growing in the gritty mix have sufficient levels of nutrients for fall and winter without promoting unwanted late-season growth.

    So should I stop the weak fertilizing in early September?

    Thanks

    Dave

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    There is lots of anecdotal stuff on the net & in print that says late applications of N will force succulent growth late in the season that won't harden off and freezes at the first frost, but I really haven't seen any difference between the plants I fertilized with 3:1:2 ratios right up until the mean temps were below 50*, and plants I was using 0-10-10 on.

    While it's true that N provides the primary building block for new growth, it doesn't have anything to do with bud activation, which is photo-period and soil-temperature related. N is a critical component of proteins, which control the plant's metabolic processes, and is also an integral part of the chlorophyll molecule, thus playing a key role in photosynthesis.

    When soil temps are above around 55*, the plant will use AND store N (as well as other elements). This store of fertilizer elements is especially critical when it comes time for the spring growth push and cold soils are making N largely unavailable.

    For a number of years I have fertilized right into winter during periods of favorable temps with MG in either a 3:1:1 ratio (30-10-10) or a 3:1:2 ratio (24-8-16 or 12-4-8) with no ill effects. I'll continue that tack this year, but as the winter chill comes on, I'll likely turn exclusively to the Foliage-Pro 9-3-6 because of it's low urea/high nitrate content, which diminishes the possibility of ammonium toxicity @ low temps.

    Al

  • suseart
    13 years ago
    last modified: 6 years ago

    Well again, thanks for a great thread, Al. Funny, I have lots of spray bottles around here ( I live in SoCal, btw) because I was using them to train hybrid cats I was breeding. I always put a little vinegar in the water because it helps deter water loving cats that don't mind a squirt of plain water when they are acting up. This past weekend I reached for a water bottle to mist some seedlings I am propagating, and realized in a panic that the bottle I almost used had one tsp of vinegar in it.

    I guess it wouldn't have been the end of the world now that I read your post. I have to find time to read your posts for like an hour a day to catch up...yikes!

    thanks again, you're a wealth of information!
    ~Susan

  • katskan41
    13 years ago
    last modified: 6 years ago

    Thanks for the reply Al. I tried some of that 0-10-10 liquid fert last year. I also read many heated on-line debates about going with a 0 N fertilizer late in the season. Some authors claimed it was beneficial to the plants while others said it was a complete waste of money. I don't know if the 0-10-10 helped or not, but the firs and pines did quite well this year.

    With the goal of allowing the small trees to store NPK for winter and early spring growth I'll keep fertilizing with weak MG 24-8-12 until it starts to get cold (ground temps around 55 or so) into mid-October.

    I certainly don't mind fertilizing them but wasn't sure if the small trees could actually make use of fertilizer late in the growing season. Since the roots continue to grow until the ground freezes they certainly need watering but was unsure whether the roots could still absorb fertilizer effectively into October.

    Thanks Al.

    Regards,

    Dave

  • gardenerme
    13 years ago
    last modified: 6 years ago

    I've been growing in containers for years, and have everything from citrus trees to ferns and dwarf evergreens in pots. All are outdoors. So, although I am experienced, I am very new to your methods and a lot of the science is beyond me (too old to concentrate I guess) What motivates me at this point is that I have plants that are growing out of their already large pots and I am desperate for solutions other than "time to put in the ground". Your logical approach is very appealing to me and the idea that I can manipulate the size of the roots is exactly what I am looking for. I am slowly converting all of my pots to your mix. I am ready to move to ferts, and really would love your advice. I would prefer to stay simple, at least to start, (such as the vinegar idea-excellent!) and will be ordering the foliage 9-3-6, however,would like your advice on how to work with my water, hence all the measurements I obtained from the water dept.

    You go for it Al! If it's over my head, I'm sure some of your other fans will totally benefit. Thanks in advance...

  • gardenerme
    13 years ago
    last modified: 6 years ago

    Just another post to bring this back up to the top in the hopes that you will see it and look at my post of 8-20. Thanks!

  • tapla
    Original Author
    13 years ago
    last modified: 6 years ago

    Oh - sorry! I thought I'd pretty much covered the thought that your water isn't too much different than mine. I don't think you need to go to any kind of extremes to try to correct the water - everything seems to be reasonable or at worst, marginal. Many of us deal with water much further from ideal than yours with good success. Adding acid to neutralize alkalinity and bring the pH down to below 6.5 would be helpful, but I only add vinegar to a few plants (while they're outdoors) on a regular basis & to almost all the others when I fertilize, and my plants are all lush/green (except a couple I thought would tolerate another summer w/o repotting - oops). ;o)

    I'm still not exactly sure what you were looking for - if I covered it. If you still have specific questions, I'll do my best to answer them.

    Take care. ;o)

    Al

  • gardenerme
    13 years ago
    last modified: 6 years ago

    Well, I have come up with an idea that works really well for me - I hooked up an MG feeder, put in a few tablespoons of vinegar (with red food coloring so I can tell when it is gone) and my plants have really rebounded! My ferns are a very dark green, my trees are very dark green, one of my container ornamental cherries actually started blooming for the first time in 4 years! Really a big difference! In addition I am slowly converting everything to your mix and have had remarkable results from that as well. My dwarf prunus incisa (which was covered in brown shrivelled leaves that I removed completely) has completely releafed out, brand new bright green leaves. And the temps here have been mid-90's to hi-90's for weeks! Also, I found the perfect wick: a long pipe cleaner my grandkids use for crafts. It is stiff enough to go in easily, and drips really well. Thanks so much for all of your generosity. I am having a great time following you. Please keep posting. I read all of your posts and learn from all of them. Thanks again!

  • ragtimegal
    12 years ago
    last modified: 6 years ago

    Hi Al-

    You provided this link in an answer to a question I had in another thread, and I have a few questions based on what I have read here, so I thought I'd revive this thread instead of starting a new one.

    It looks like you switched to the Dyna grow 9-3-6 last year. Do you still use CRF in your soil mix if you are still using this fert?

    Also, I have alkaline water, between 98-109ppm, depending on which facility the water is coming from, with a pH of 8.0. Will simply adding vinegar to the water, as you recommended above, solve any issues that would stem from having high alkalinity and high pH, and are there other issues I may need to address separately that would result from the high alkalinity and pH?

    Did you still have problems with Iron deficiencies after switching to this new fert mix? (or do you still use the Iron chelate?)

    Lastly, and this may be a repeat of a similar question somewhere else...I'll be growing tomatoes in my containers. Would you recommend the addition of the Pro-Tekt to help boost the K without increasing N to help with bloom/fruit production? I thought I may have seen you mention that.

    I had hoped to try an organic route to fertilizing, Dan had some great suggestions in a recent thread on Organic Container gardening in this forum, and I may try some experimentation of my own, growing two of the same variety plants in the same soil mix, (separate containers, of course) but using two different fertilizing methods to see if there is a detectable difference.

    Thanks so much for all of your help!

    RTG

  • tapla
    Original Author
    12 years ago
    last modified: 6 years ago

    "It looks like you switched to the Dyna grow 9-3-6 last year. Do you still use CRF in your soil mix if you are still using this fert?"

    Actually, I rarely use the CRFs at all. I like the near complete control the soluble fertilizers give me in containers. I'm pretty diligent about fertilizer applications, so I really don't need the CRFs to cover the 'in case I forget' base, or for any minor elements they might supply. I included them in the soil recipes to make it easier for others. As long as you're faithful to your nutrient supplementation program, you can easily do w.o them. If you think you'll be lax at times, I'd include them.

    109 ppm alkalinity is nothing to be overly concerned about with fast container soils. It would be interesting to learn how the Ca and Mg levels are though. Alkalinity is related to pH because alkalinity (practically speaking and for our applications) determines your water's resistance to pH changes. If you have water 'A' at a pH of 9.0 with an alkalinity of 75 mg/L CaCO3, and water 'B', with a pH of 8.0 (a full point lower to begin with) and alkalinity of 300 mg/L CaCO3, it will take about 4 times as much 35% H2SO4 (sulfuric acid) to bring the water with the lower pH down to That aside - your water is better than mine, so I really doubt you'll have Fe/Mn issues if you're using either the 9-3-6 or MG. I will say though, that bark/peat soils have a potentially high Fe:Mn ratio, so applying Fe w/o Mn could easily create a deficiency of Mn. If I were in your shoes, I would do nothing until I actually saw evidence of an Fe deficiency. Then, I would acidify. Oh - the other likely cause of an Fe deficiency is too much P, which combines with the Fe to form an insoluble precipitate, so avoid the high P fertilizers - they are useless unless you are using them to supply the exact amount of P needed while intentionally (severely) limiting N.

    I used this strategy last year: I fertilized with regular dosages of 9-3-6 until the plants were well established. I then cut way back on the dosage and added ProTeKt to the solution. I rather like to envision that I used the added K (and got the benefit of the added silicon) to change the fertilizer ratio to 3:1:3 from a 3:1:2. This allowed me to reduce the dosage of N (reducing vegetative growth) while still having adequate P and K.

    Take care.

    Al

  • jodik_gw
    12 years ago
    last modified: 6 years ago

    Hi, Al! I'm not sure I responded to this thread... so, just in case I didn't, I want to say thank you... I wasn't sure my fertilizer program was correct, but I see now that I'm doing fine.

    I use an all-purpose liquid houseplant fertilizer, and I add a bit of STEM. I use it all at about half strength every other time I water. Every once in a while, I use a fish emulsion liquid that I happen to have on my shelf. So far, all my indoor plants seem to be thriving.

    The combination of a rather constant feeding program and the very aerated inorganic medium I now use have given me the very wonderful ability to grow healthy and beautiful bulbs and other plants! And it's all due to your teachings! So, thanks! You've made me a better gardener, and I appreciate very much that you've shared your knowledge!

    A green thumb is nothing more than applied knowledge!

  • tapla
    Original Author
    12 years ago
    last modified: 6 years ago

    Thanks, Jodi. You've been a great advocate of many of the things I've said on the forums, and I'm really glad they seem to have helped you. ;o)

    This thread will be cut off soon. I hope GW will allow a few more posts so I can refresh this one and repost it with a link back to this thread. Please refrain from additional posts and I'll try to attend to it this evening.

    You guys are all great!

    Al

  • tapla
    Original Author
    12 years ago
    last modified: 6 years ago

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  • vidyut
    7 years ago
    last modified: 6 years ago

    Fascinating thread and thank you!

    With regard to the self watering containers (I've never seen one but was wondering if I should DIY just because it was a possibility - now I won't), but surely if you needed to wash out salts, after the water was used, instead of refilling the watering container, you could top water it till the water drained and overflowed from whereever it overflows when the tank gets over filled?

    Probably not most efficient, but doing it a few times would reduce salt build up?

    Ignore if this is a stupid question, since i obviously have never used one. Just thinking that if this makes sense, I may still try to make one :p

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