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Lack of Potassium on Peas and Lettuce and Swiss Chard Seed

daleyc
16 days ago

Hey Folks,

not sure which forum this should be in but what the heck...

I'm putting in my seeds for the first time since I got my soil analysis (yeah!! i finally got it)! I'm super low on Potassium. (34). I've been reading up on it but I haven't been able to get the info i need. Should I apply the potassium from the bag? How important is it to these crops?

Also, the info on the relationship between Nitrogen and Peas has been a bit ambiguous. It seems like the Nitro -Pea relationship is important. I'm not sure how to read the Nitrogen level from the report. Does 18 sound right? Could someone explain that to me?

Thanks in advance and wishing all a spectacular garden season!

Comments (38)

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    16 days ago

    Potassium ia primary nutrient. You can get it in many sources, including potash and wood ash. Though you might be careful with those if your soil is highly alkaline. Most soil analysis labs give mitigation instructions if they measure a deficiency. Did yours not give you recommended fertilizer? Peas are legumes, and they mostly fix their own nitrogen, assuming the right bacteria is in the soil, which there almost always is. Note that nitrogen is an assay number that needs to be regarded with a little skepticism. The reason is that plant-available nitrogen is HIGHLY leachable, so it comes and goes. That being said, 18ppm is OK for immediate crop needs, but may need to be amended later in the season.

  • daleyc
    Original Author
    16 days ago

    Thanks daninthedirt

    my report did offer adjustment info but I haven't absorbed all the info. However Id like to put my peas seeds in tomorrow. Will the Potassium # effect their growth or is it not a big deal.?

    As far as the rest of my plating this summer I will reader the report in full and make adjustments to the soil as needed,

  • kevin9408
    16 days ago

    "Should I apply the potassium from the bag?" Bag of what? Very few bags are created equal so be specific. If 34 is parts per million (PPM) then it's low and above 181 PPM is considered sufficient.

    To increase the soil 1 PPM for a square foot you would add 0.02 grams per sq. ft., so to raise your soil to 180 parts you would need to add about 3.12 grams per sq. ft. This is 100% potassium so if "your bag" labels potassium 50% you would need to double it to 6.24 grams per sq. ft. If "your bag" is 10-10-10 the potassium is 10% you need to add 28 grams per square foot.

    If the potassium level is truly 34 PPM you will have very sickly looking seedlings before they die.

    Nitrogen levels can change from one week to the next, and from 6" deep to 9" and 12 deep", it depends where you pulled your sample. The optimum level of nitrogen for a vegetable garden is 25 - 40 PPM and he same above apply for nitrogen or any fertilizer, 0.02 grams per sq. ft. for each 1 ppm you want to raise it.

    In your case just mix in a cup of 10-10-10 fertilizer per each 10 foot row and call it a day. back to "your bag", if you use cow manure you'll need to add about 300 grams, (10 to 11 ounces) per square foot. A 100 square foot garden you'll need 62 pounds, and this is minimum.

    daleyc thanked kevin9408
  • daleyc
    Original Author
    15 days ago

    I see the pattern of providing Potassium and it being leached out. Is chealation by soil colloids only available in compost (I understand the premise but am not sure how to apply it to my situation).

    As far as compost go's...are we talking manure? lobster and oyster? Vegie, plant or a combo?

    I cant help but think that if I use the Espoma Potash 0-0-60 (that's the bag i use)

    why cant I start with sprinkling the Potash around the individual plants, watering them in and then find a more permanent solution.

    Yes, daninthedirt, I am so happy to have finally gotten the testing done. Now, I see I have to read all the info and suggestions more thoroughly

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    15 days ago

    Well, I believe the chelation is being done just in the humus part of the compost, which is 5-10% of the mix. There are lots of different chelating agents (e.g. citric, ammoniac, EDTA), but few are as easily available to the residential small gardener as compost. Humus in compost comes from organic matter, and is pretty much just fully broken down compost. So just about any compost will do. The cations "stick" to the chelating agents, Certainly start out just amending the soil with potash, but my point was, in the long run, you'll want to make your soil grab onto the potassium better. Do abide by the instructions on how to amend with potash. Too much potassium can be worse than not enough. It can interfere with absorption of other nutrients. Be aware that potash is not an instantaneous supplier of potassium, It needs to break down in the soil, and that can take weeks or months. I believe that 0-0-60 will give up only about half of its potassium in the first year. It's not entirely water soluble.

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • kevin9408
    14 days ago

    Spreading the 0-0-60 at a rate of 7 grams per sq. ft. (by weight) and mixing it in IS the permanent solution to bring your potassium PPM up to an adequate level. This is what every farmer and gardener does before planting so Mix it in first. But after you spread the potassium I suggest spreading about an 1" to 1 1/2" layer of compost down the rows where you're going to plant and rake it all in the top 3" to 4" layer, this is what I do before I plant.

    Compost is 40% -60% organic matter (OM) and made up of the living, dead and very dead OM. The very dead is where you'll get a little amount of nutrients at first and the other two will provide more nutrients later on in time. Most important is the OM and will give nutrients something to cling to, but more isn't better and about a 5% total OM in the soil is all you need, Compost is low in major nutrients and potassium may only be 0.4% to 0.8%. Cow Manure will have a little more but the total OM is still high, so with your fertilizers add the compost or cow manure.


    daleyc thanked kevin9408
  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    14 days ago
    last modified: 14 days ago

    Well, the point is that yes, farmers apply potassium supplements before planting. But they do it routinely, because that nutrient isn't necessarily permanent unless you take some trouble to extend its availability. But I'll repeat that compost is a poor fertilizer by weight. Of course, some people try to make up for that by just using a lot of it. More to the point, compost is not an immediate source of nutrients. What little it has is released over time as it degrades in the soil. Compost is a soil structure amendment, and does help preserve moisture and nutrients, though. I use entirely leaf compost, which is the least nutritive of all composts, but I dig in a lot every year.

    Let me add a little more about chelation. "Metal" ions, including potassium, are what you get when mineralized potassium slowly dissolves. But those ions are chemically very fragile, and they will oxidize, leach, and precipitate readily, making them unavailable to plants as nutrients. What chelation sites (e.g. ligands) do is protect the ion from those removal mechanisms. The ions are bound loosely to organic ligands, but can be digested by plants readily.

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • kevin9408
    14 days ago

    About fertilizer Antagonism. As Dan said using to much Potassium will lead to a conflict with other nutrients, but most nutrients will have conflicts with others if the total balance is out of wack. The relationship can be seen using the Mulder's Chart and also shows the stimulation of nutrient uptake of other nutrients. A balance is necessary, and even if there is a little much potassium it won't hurt if the other nutrients are balanced. With more than the adequate amount of all nutrients in the soil plants adapt and just don't grow more roots than they need. This can easily be seen in hydroponics with much smaller roots when nutrients are always available.

    With the potassium you need to be aware of all nutrient levels to maintain somewhat of a correct balance between them all. Too much Calcium will effect the uptake of 7 different nutrients. One nutrient most overlook is sulfur, some call it the 4th macro nutrient and essential to all plants. The hardest part of the gardening is the balancing act. I find it hard to agree with your soil test numbers and believe there was a problem, or error taking the sample. Maybe you live in a new housing development where all the top soil was removed, or it was someones old sand box. An old parking lot?


    daleyc thanked kevin9408
  • daleyc
    Original Author
    14 days ago

    ok...lots to take in...still reading...talk soon

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    14 days ago
    last modified: 14 days ago

    Kevin makes a good point. 34ppm of potassium is VERY VERY low. Now, the mineral content of native soil has TOTAL potassium in the tens of thousands of ppm. Weathering dissolves that potassium and puts it in plant-available ionic form, usually in hundreds of ppm. I'm presuming the latter is what was measured (STK="soil test potassium"). As such, it's hard to get soil with almost no ionic potassium. Even with pure sand.

    Not sure where you are, but I'd query your local extension about this. Ask them if such low potassium values are common in your area, and specifically what ag workers there do about it. The question is whether your values are typical for your area, or if you have something really bizarre. Was *anything* growing on this soil?

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • daleyc
    Original Author
    13 days ago


    ok

    I've read it all. All your posts, all the info from my analysis and while I cant get a local person to verify my results, i do have a call in to the folks who did the report.

    Thank you both for your thoughtful and inciteful sharing of your knowledge.

    I did read on the extension that I can rake the Potash in with the footage and the ppm. I guess I have to learn those calculations. Any ideas as to how a non numerical person can learn this?

    Question...The best compost to use for chelation. "Metal" ions straight up is Humus?

    Hopefully I can find out soon whether the # is even accurate (though I submitted several samples) The samples came from a garden that I've been working for years. hmmm


  • daleyc
    Original Author
    13 days ago

    What do you (plural) think re the raking it in?

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    13 days ago
    last modified: 13 days ago

    I don't think it matters how you apply it. Raking, digging, just throw it on top. As it dissolves, it will work it's way into the soil. The important thing is how much to use. You asked about which compost to use. I told you that the chelation is on ORGANICS. All compost is organic. What comes through a bovine went in as organic, and comes out as organic. Now I will add that seaweed is high in potassium, so composted seaweed might make a great amendment.

    Again, querying your extension would be very smart. That's what they're there for.

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • daleyc
    Original Author
    13 days ago

    I thought that chelation attached better to the humus than other composts. . As for seaweed, I'll have to look around. I haven't seen it in my local suppliers. What about seaweed fertilizer. Neptune's Harvest has a seaweed formula. Good?

  • kevin9408
    13 days ago

    Question. In the years you've been working this garden soil have you ever put anything into it? Fertilizers, composts, anything? If so what.

    daleyc thanked kevin9408
  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    13 days ago
    last modified: 11 days ago

    Chelation does attach to humus. Humus is 5-10% of well-composted compost. If you don't have local seaweed around, buying composted seaweed isn't an economically smart choice. Much better to just buy potash.

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • daleyc
    Original Author
    13 days ago

    yes, Kevin, I put fertilizers, compost of all sorts, worm castings.

    You know, I'm feeling kind of sad. I so look forward to the spring to start my seeds, raking the soil, adding the compost and planting my flowers and veggies and this potassium thing is definitely putting a damper on my joy. I think I was better off just not knowing. I always have beautiful flowers and the veggies never do that well, probably because the potassium.

    I'm going to rake in the potassium and fertilize with seaweed fertilizer and have some fun!


  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    13 days ago

    Hard to imagine why it's better off not knowing if your vegetables never did that well. At least now you have a path to success.

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • daleyc
    Original Author
    13 days ago

    Don't get me wrong. I'm still going to work with the veggie garden and get that potassium going but I'm just not to make my crazy about it. I'm gonna hang in the garden

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    12 days ago

    I feel compelled to add that this is EXACTLY why people should get a soil test done, especially if it is a new bed. Often some mysterious reluctance to doing that. What you'll learn is EXACTLY what you need, and also what you don't need. Otherwise, you just spend money piling broad-spectrum fertilizer on, hoping you hit the target somehow. That's like doing target practice blindfolded. Now, as in the case here, if you get back some very unusual result, it's worth looking into more carefully.

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • daleyc
    Original Author
    12 days ago

    Thanks Dan!

  • kevin9408
    11 days ago
    last modified: 11 days ago

    Daleyc said it, "Any ideas as to how a non numerical person can learn this?" Yes, a lot of reading and learning and evolving. So while you learn spread the 0-0-60 at a rate of 7 grams per sq. ft. (by weight) to achieve 180 ppm. This isn't permanent because the plants you grow will take up a lot. To be exact pea's will take up 30 to 40 ppm so do you plan to do a soil test every year? The Potassium under the pathways will still be there so how do you compensate for the difference? I do not fertilize what I don't grow over, including paths.

    I've never fertilized my entire garden, Not once in 25 years. I only fertilize the rows I plant in and only what the plant will use each season give or take a few parts per million, (or maybe 10). With Information available on nutrition requirements for every plant anyone wants to grow it has already become very easy.

    For your pea's the nitrogen they need in mineral soil is 40 ppm of nitrogen, for phosphorous 30 minimum to 50 ppm and potassium 30 to 50 ppm. For lettuce nitrogen is 100 to 140 ppm (depending on type) and about the same P and K as peas. Swiss Chard is 100 ppm for nitrogen and the P and K is same as the other two. Notice the big difference in nitrogen between lettuce and peas? If it;s organic soil the numbers are off the chart at 2 to 3 times as much but I don't know why because I don't do organic. Could be the high level of OM the soil the CEC is very high. As I said before excess isn't bad if it's balanced.

    So I will fertilize each type of veggie different depending on their needs determined by science, and the only big difference would be nitrogen. I consider this neutral to loss or gain But I'm sure it has changed some and could be the same as yours for all I know. I don't care and the next guy can do some soil tests and fix it. Chances are high my 5 acres of land in a sea of urban development will be bought for development or taken through eminent domain, and all the top soil will end up in the back of a truck. It's not if but when.


    daleyc thanked kevin9408
  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    11 days ago
    last modified: 11 days ago

    I'll add that I really don't fertilize my garden much either. In fact, my soil tests show that I've got loads of P and K, so I just throw some N on every few weeks. Uber cheap lawn fertilizer. Ammonium sulfate. Don't pay money fertilizing your fertilizer! I do sprinkle a little boron on when I plant my beets though, since I don't test for that, and beets really need it.

  • daleyc
    Original Author
    11 days ago

    The information you've given me is helpful.. I'm going to print it out and highlight the parts that I can apply to my garden.

    Its the ppm per square foot stuff that I'm having a hard time with but as you said 'a lot of reading and evolving'' I've got a Step by step fertilizer guide from Umass along with an 'interpreting your results sheet'. I'm going to use them + the package info to figure numbers

    What is the CEC (should i know that by now?)

    I don't fertilize in mass either. I do, however apply compost to the bed.. The Aggy guy said I should rake the potassium into the whole bed rather than putting into planting holes.

    I see the different numbers with the lettuce and the peas.

    I'm working with the numbers this weekend Wish me luck (I'm thinkin' I'm going to need it)

    But you know....i spent the

    day working in my home gardens as opposed to my community plot which is the plot where I do my vegies and cutting flowers, (and have the problems) and I had a wonderful time!

    I enjoy the chemistry of gardening but digging in the dirt is so fun!

    Thanks again!


  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    10 days ago

    Someone with better chemistry background should answer, but I BELIEVE CEC is just the general ability of soil to grab onto nutrients. But that isn't a chemical bond. It's a pretty light touch. Just electrostatic attraction. Chelates actually grab nutrients tightly and prevent them from forming insoluble compounds which are not plant-usable. What makes a high CEC is largely colloids, which are just really big molecules. Organics in compost do that. So it's important to have high CEC, and even better to have chelates responsible for it.

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • kevin9408
    10 days ago
    last modified: 10 days ago

    CEC means "Cation exchange capacity" and it's nice to know but not something people need to know. It's not something soil test labs will calculate unless requested and requires a magnesium and calcium test to do one. It can be estimated knowing the type of soil and the tested organic matter percentage of your soil and it should be on your test results. So what kind of soil do you have and what was your organic matter percentage?

    Most nutrients have a positive electrostatic charge and are called "Cations" All soil and organic matter has a negative electrostatic charge, so the Cations will attach to the surface of soil/OM particles because opposite charges attract each other. This is how soil and organic matter hold nutrients with the simple reason opposites attract.

    How many Cations thesoil/om can hold is the "capacity". the amount of total surface area of the soil/om determines capacity, and the finer the soil the more it can hold. What's left of the CEC is the "exchange" of Cation's from soil/om particles to the plant roots.

    The plant roots release positive charged hydrogen ions, and they attach to the negatively charged soil particles forcing it to release a nutrient Cation that the plant root takes up. This is the exchange, It's a swap of a nice plump hydrogen ion for one of the 9 nutrient cations. So CEC is how many Cations the soil can hold that can be exchanged with the plant, or just held.

    The exchange of the other half dozen negative charged nutrient ions, called Anions, is a another story. Boron has no charge and considered neutral, it's the only nutrient plants do not take in as an Ion (Cations, Anions). It's also another story but Boron is the most deficient nutrient world wide because it has no charge so never sticks around in the soil, because there isn't anything to cling to. looking up the boron cycle shows how we get it.

    I know nothing about Chelates and have no clue what they are or do. I guess I should read up on the subject and find out, I could be missing something that could help my plants.

    daleyc thanked kevin9408
  • daleyc
    Original Author
    9 days ago

    Gentleman

    I do not consider my self to be a stupid woman but when it comes to the numbers in gardening i think i must be a moron. Honestly, I will never understand the ppm's and the pounds and the square footage. I do, however, understand the NPK ratio and how they work in the soil. I understand the importance of each element and of the micronutrients except I kind of understand chelation and CEC. Moving on, I must speak in terms that i understand. Are you game? If not, i understand.

    OK...I have read all my reports, my fertilizer application instructions and 'Interpreting you soil test results '.

    I need potassium, lime and calcium. The Potash says to apply 1lb per square foot. It also says that I can apply tsp around the drip area per plant. That seems to be more Dale friendly I'm just winging it here. (remember, i cant do numbers.). I do understand from my soil test that i need lime and one area need calcium. I think that the calcium and other macro/micro nutrients can be added through the fertilizer. Not sure how to figure the lime.

    Can I put down the additives all at once? Mix them in or layer on top?

    As my greatest concern is the potassium. After the initial application (1 tsp? Seriously?) Will a high potassium fertilizer work or is there something else I could/should apply?

    Once I figure out the lime can I apply potassium and lime at the same time?

    If I use a high potassium fertilizer after initial addition will i be good? I can get other micronutrients and macronutrients through a fertilizer? All my other numbers aren't great but are within range. Lastly, I do not see a Nitrogen number on my results. Is Nitrate the same? Its value is 15. My Soil Organic Matter is 4.9%. Also, is it possible to add too much compost?

    I don't see a straight out nitrogen #. I've got Nitrate-N-(NO3*N))mm Is that the same? Haven't quite understood your Nitrogen #'s

    So i guess my biggest question for the immediate future is how to add? mix? layer? and how much. Can I later my potassium, lime and general fertilizer per plant without doing all the numbers...or cant I? If you don't think its possible and I'm pretty sure you don't. you've been very informative and helpful

    some options

    3-4-5

    3-4-6

    15-7-32

    10-3-10

    MG tomato 18-18-21

    Too much ask?

    That's ok...i get it :)

    Thanks guys!

  • vgkg Z-7 Va
    9 days ago

    "OK...I have read all my reports, my fertilizer application instructions and 'Interpreting you soil test results '.

    I need potassium, lime and calcium. The Potash says to apply 1lb per square foot. Need potassium, lime and calcium. The Potash says to apply 1lb per square foot. "


    My bold, no expert here on amounts to add but that sounds like a bit much.

    daleyc thanked vgkg Z-7 Va
  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    9 days ago
    last modified: 9 days ago

    Um, what? 1 lb/square foot for potash? Where do you get that??? The usual recommended application rate is roughly 100 lbs/acre, which works out to about 1 lb/400 square feet. You throw 1 lb of potash on a square foot, and it's going to be a pretty thick layer of potash.

    As noted, please don't pay a lot of attention to N. It comes and goes. And who says you need lime? Is your soil overly acidic? What's the measured pH of your soil?

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • daleyc
    Original Author
    9 days ago

    obviously I made a typing error. It is 1lb per 100 sq foot honest mistake).

    The lime recommendation came from my UMass Extension soil report. I had 3 samples tested. pH 5.7, 6.4 & 5.8. I didn't think that was terrible but for all 3 samples, flowers and vegies, the recommended target is 6.5.


  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    9 days ago
    last modified: 9 days ago

    You could use a little alkalinity, but be careful. Potash is alkaline, and will deacidify. So if you're applying a lot of potash, you may not need lime. Sprinkling it on the surface is a lot easier than raking or digging in. Overhead irrigation will make it penetrate. If, however, you're using buried drip lines, it won't. If your drip line is more than a few inches deep, even raking it in won't serve the need.

    1 lb is about 100 tsp so, by that 1 lb/100 sqft recommendation, 1 tsp/square foot would be right for potash. So 1 tsp spread around each plant would serve.

    Given your soil test results, I wouldn't worry about anything other than potassium. That needs a BIG FIX.

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • daleyc
    Original Author
    8 days ago

    Thank you Dan for giving me a number that I can compute (remember, I am number challenged).

    Does the tsp application work for all my plants?

    Do I need to do this regularly throughout the season?

    Are you ready to ban me from the forum ? :)

    Lots of info lots of thinking

    much appreciated...happy to hear more


  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    7 days ago

    Usually, potash is applied once per year. It doesn't leach quite as easily as other nutrients. I would presume the application rate is the same for all plants. We appreciate you bringing good questions like this to the forum, and the discussion may well help others.

    daleyc thanked daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
  • daleyc
    Original Author
    7 days ago

    Thank you :)

  • kevin9408
    7 days ago

    Dan, you hit the nail on the head. 1 pound per 100 sq. ft. works out to 1/16 ounce per 1 square foot. A 1/16th of an ounce equals 4.55 grams, so I weighed 1 teaspoon of 0-0-60 (KCI) and it was about 4 1/2 to 5 grams. well done. I also weighed out a pound of KCI and it equaled 2 cups, so 2 cups per 100 sq. ft. is what you'd use if you plan to do the entire garden area.

    Daleyc, 20 years ago all of this was like an alien language to me, so I took it down to the lowest factor and learned my way up to make sense of it all. One very important lesson you really need to learn is how math is used to convert numbers into something you can work with just as Dan did.

    Good luck with you garden and hope it all works out for you.

    daleyc thanked kevin9408
  • daleyc
    Original Author
    6 days ago

    workin on the math...be in touch when i make headway

    Thanks guys!

  • daleyc
    Original Author
    5 days ago

    16 oz=100 sq ft

    16 divided by 100=.16 how do I turn .16 int soil with o 1/16

    1/16 = 1 sq ft

    1.6oz = 45.3 g

    1tsp = 5.69g (close enough?)

    I’m having decimal issues, but I think this is right

    These measurements are all based on amending with granular fertilizers (etc).

    Do you only use the granular?