A Couple Questions For New Citrus Growers

3 years ago

Good Afternoon Everyone!

I have been reading the message board here for the past few weeks after inheriting some citrus trees, and have (mostly successfully) been trying to find already-answered questions of ours before I post anything. However, I do have some lingering questions that are of importance to me and my S.O....If anyone can help answer a few of these questions (or all), that would be great!

Background Facts:

Location:

Orange County, CA

Trees Grown:

Meyer's Improved Lemon
Eureka Lemon
Key Lime
Bearss Lime
Navel Orange
Valencia Orange

Original Tree Containers (Late July - This Past Tuesday):

15 Gallon Black Plastic Containers

Current Tree Containers (This Past Tuesday - Present):

17" Pennington Large Terra Cotta Pot

Soil Used:

Dr. Earth Cactus & Succulent Potting Mix

Tools & Sprays Used:

Luster Leaf 1820 Rapitest Soil Moisture Meter (Reads 0-10)
Grow More 7450 8-Ounce Organic Iron Chelate Concentrate (Liquid In Soil & As A Spray For Leaves)
Down to Earth Organic Citrus Fertilizer Mix 6-3-3
Neem Oil Spray

Question #1: Soil moisture & Perlite Content

When we began this odyssey, we simply replanted the existing root-bound trees from their nursery 5 gallon pots to the new 15 gallon pots. However, as the weeks progressed, we noticed that the soil at the bottom half of the plastic pots was usually very moist (9-10+ On Moisture Meter) while the top half of the plant was sometimes down to a 1-2 on the moisture meter and in need of some water. In addition, we were having lots of mushrooms growing in the top of the pots and slime mold issues at the bottom of the pots.

To "fix" this, we added fair amount of perlite into the soil in the plastic containers. This ended up largely fixing the issue of the soil being very wet for prolonged periods. However, once we moved the plants into the new terra cotta containers this past Tuesday evening (while keeping the plants in the same soil), we have noticed the soil drying out much quicker now. I expected this to a degree since the terra cotta would allow for greater moisture wicking and due to the fact that pots should naturally dry from the outside inwards, but I am surprised at just how fast the perlite-infused soil is losing its moisture compared to the original soil in the root ball.

For reference, as of this morning, most of the trees are reading <5 when the moisture is measured at the edge of the pot (about 6-7" away from the tree). Meanwhile, the moisture meter reads 8+ when measured within 2-3" of the tree.

To better illustrate, I made the following table:

Figure Above: Tree Moisture On Friday Morning After Re-Potting And Watering On Tuesday Night. Note that the Meyer Lemon and Key Lime Were Removed From Root-Ball Due To Root Rot Issues (See Question 2).

Question #2: Replanting After Some Root Rot Issues

Regarding the meyer's improved lemon and key lime trees, both unfortunately experienced some minor root rot while they were in the old soil and plastic containers. Because of this, my significant other and and I removed the trees from the root ball soil and carefully removed rotted/affected roots.

After cleaning everything up, we repotted these with new soil/perlite in their new terra cotta pots on Tuesday. While we expected shock loss and other issues, we are fairly surprised at just how pronounced it has been. Both trees shed their 1-2 pieces of fruit and almost all of their leaves have come off as well. I accidentally bumped into the pot this morning and that alone sent a dozen leaves to the ground.

Based on the pictures below of the plants today, what do you feel the prognosis is? Are these things salvageable?

Figure Above: Key Lime Tree

Figure Above: Key Lime Tree Up-Close

Figure Above: Meyer's Improved Lemon Tree

Question #3: Cutting Or Leaving Alone This Massive Branch On Our Bearss Lime Tree

The coolest tree so far is the other lime tree, and how fast it has grown. However, it has one branch that has significantly outgrown the others to a fascinating degree. In the 7 weeks of owning this tree, this branch has grown by a solid 2 feet - if not slightly more. After reading some various posts on here, it seems that it may be wise to trim this branch down by a fair amount if I want a "fuller" looking tree. Is that the consensus, or should I just let this bad boy keep growing and hope the other branches start to catch up (even though this branch has slowed down in recent weeks)?

Figure Above: Massive Branch Growing On Bearss Lime Tree

Figure Above: Same Bearss Lime Tree: Note The Size Of This Growth Compared To The Rest Of The Tree

Question 4: Post-Pruning Tips

After pruning, do you like to do anything in particular to protect the exposed parts of the tree's limbs where cuts were made, such as touching them up with pruning paint? Or do you like to just let it heal on it's own?

Question #5: Grow Light To Help On A North-Facing Deck

When we got these trees, we were getting roughly 10 hours of sunlight daily. However, in only a matter of weeks, we have seen that amount be reduced to only 6 hours per day and falling. This is mostly due to the sun's lowering angle and how it is interacting with our building's design. We are moving to a new complex when our lease expires in late November, and will be getting a south-facing deck at our new place as to avoid this issue now that we have plants to keep alive.

Conclusion

As you can tell, we are trying to do what we can to ensure wonderfully healthy and thriving plants down the line, but need guidance as all people starting in a newfound hobby might need. With that in mind, any help is greatly appreciated, and if there are any questions or clarifications needed, I will certainly do my best to answer them. Thank you again!

Featured Answer

tapla (mid-Michigan, USDA z5b-6a)

3 years ago

1) When we began this odyssey, we simply replanted the existing root-bound trees from their nursery 5 gallon pots to the new 15 gallon pots. However, as the weeks progressed, we noticed that the soil at the bottom half of the plastic pots was usually very moist (9-10+ On Moisture Meter) while the top half of the plant was sometimes down to a 1-2 on the moisture meter and in need of some water. In addition, we were having lots of mushrooms growing in the top of the pots and slime mold issues at the bottom of the pots. Moisture meters measure electrical conductivity, not how much water is in the soil. Salts from fertilizer solutions and tapwater have a significant impact on moisture levels. To confirm, insert the (cleaned) probe into a clean cup partially filled with distilled water and note that it reads DRY. Sprinkle a little table salt or sugar into the water and watch the needle move to WET. Using a wooden "tell" to "tell" you when it's timed to water will allow you to determine appropriate watering intervals. See Using a Tell below. What's important is the moisture level at the bottom of the pot.

Mushrooms are not a problem and are not clear indication your soil is to wet or dry. The fruiting bodies you see means only that the particular species of fungi producing the mushrooms find conditions in the pot favorable. Plants live harmoniously with thousands of species of fungi where they naturally occur, with only a few species being a problem, and most of which would be covered by the umbrella term 'damping off diseases'.

The more water retentive the media you're using is, the more careful you need to be about over-potting. What size pot you can pot up to w/o running into the limitations imposed by over-watering (soil remaining saturated for an unhealthy period of time) is determined by the current size of the root mass and your choice of grow medium. Some media would allow you to plant a seed in a 55 gallon drum filled with soil without an issue. See Choosing an Appropriate Size Container below.

With this in mind, would you fine folks suggest mixing in more Dr. Earth (we still have an entire bag remaining) into the existing perlite-infused soil to keep the moisture content more evenly distributed? Adding perlite to a water retentive medium actually decreases o/a aeration on a per volume basis. Imagine a jar of filled completely to the rim with sand. You conclude the tiny air spaces between the particles is inadequate, so you add perlite. When you add a perlite particle, the jar overflows a volume of sand equal to the volume displaced by the perlite, but it also displaces the air space between the sand particles. Perlite is a 'closed cell' product, so it has no internal porosity. So, as you keep adding more and more perlite, the volume of air porosity decreases until the volume of perlite equals a threshold proportion, which occurs when there is exactly enough sand to fill all the air spaces between the perlite particles. That is the most difficult medium to grow in because the perlite simply takes up space, adding no air porosity but reducing the volume of sand/soil which can be colonized by roots. Your best bet is to start with a very large fraction of coarse materials and add only enough fine material to bring water retention up to a point where watering intervals are something you can deal with. 3 days is about idea; and, if watering intervals stretch out to more than a week, you are leaving potential in terms of growth rate, vitality levels, yields (of blooms/fruit), and eye appeal. Much More about Container Media and Water Retention

2) Because of this, my significant other and and I removed the trees from the root ball soil and carefully removed rotted/affected roots. While we expected shock loss and other issues, we are fairly surprised at just how pronounced it has been. I accidentally bumped into the pot this morning and that alone sent a dozen leaves to the ground.

Based on the pictures below of the plants today, what do you feel the prognosis is? Are these things salvageable? Likely cause: A) Citrus prefer to be repotted in early to mid-spring. B) If you bare rooted (or nearly bare-rooted) and didn't take precautions to keep the roots wet at all times during the repotting session, you probably lost a large fraction of the fine roots that do all the plant's heavy lifting when it comes to water and nutrients. The lost leaves (and fruit) were a drought response due to an insufficient volume of functioning roots to keep all the plant's parts hydrated. This slowed synthesis of a chemical messenger/ growth regulator (auxin), which must continually flow across something called the abscission zone (where the leaf/fruit is attached to the branch) to prevent an abscission layer from forming. An abscission layer, once started is irreversible, and effectively 'walls off' the leaf from the rest of the plant. Once the abscission layer forms the leaf/fruit separate from the plant under it's own weight or with some help of a breeze or bump from the plant's owner. This is a survival mechanism that allows the plant to conserve moisture. Prognosis: good to very good as long as the plant was reasonably healthy before the shedding and you avoid over-watering. Any concerns would center on how much energy the plant has in reserve and the root's health a ability to function normally.

3) The coolest tree so far is the other lime tree, and how fast it has grown. However, it has one branch that has significantly outgrown the others to a fascinating degree. In the 7 weeks of owning this tree, this branch has grown by a solid 2 feet - if not slightly more. After reading some various posts on here, it seems that it may be wise to trim this branch down by a fair amount if I want a "fuller" looking tree. Is that the consensus, or should I just let this bad boy keep growing and hope the other branches start to catch up (even though this branch has slowed down in recent weeks)? The key factor is whether the plant is grafted and whether or not the branch arises from the scion or the understock. If it is part of the scion, prune it back to immediately above the lowest branch. If you like, you can leave 2 leaves on the stub above the lowest branch. New branches will grow in the axils (crotch) of those leaves. There is almost no hope the other branches will "catch up" to the wild shoot. Restraining it will force more energy to other branches. If, however, the shoot emanates from the understock (below the graft), remove it entirely unless you have reason to want the understock to 'take over' the tree.

4) After pruning, do you like to do anything in particular to protect the exposed parts of the tree's limbs where cuts were made, such as touching them up with pruning paint? Or do you like to just let it heal on it's own? Trees in the landscape should not be treated with any type of wound dressing. Trees in containers will benefit from being treated. You can but 'cut paste' used on bonsai trees, or, you can paint the wound with waterproof wood glue. Some bonsai practitioners use Vaseline or even Preparation-H to cover the wound. Keeping the drying air away from the wounded tissue limits the wound from growing larger and facilitates the callus tissue's ability to smoothly roll over the wound. I use wood glue and carefully paint (with a toothpick) only the wound itself and any exposed cambium at the perimeter of the cut. Make cuts thus:

5) When we got these trees, we were getting roughly 10 hours of sunlight daily. However, in only a matter of weeks, we have seen that amount be reduced to only 6 hours per day and falling. This is mostly due to the sun's lowering angle and how it is interacting with our building's design. We are moving to a new complex when our lease expires in late November, and will be getting a south-facing deck at our new place as to avoid this issue now that we have plants to keep alive.

However, would an outdoor grow light be something we should consider for the next 3 months? Is there a recommended light than can be plugged into an existing outdoor light socket - or is that even a suggested set-up in the first place? Given this new information, it's very possible the reduction in photo load is the underlying cause of the shedding. I've never used supplemental lighting outdoors, but there is no reason you can't. The main concern is lanky new growth. What you COULD do is simply do the best you can for now (sans supplemental lighting) and plan on pruning off all lanky growth in the spring. If your focus is primarily on appearance, you should be in a rhythm that has you pruning hared in the spring, then pinching during the summer, stop pinching in fall and allow the tree to grow w/o being pruned for the winter, then start the new cycle in the subsequent spring by again removing all the winter's lanky growth.

This might be helpful: Long Term Care of Trees in Containers

Using a 'tell'

Over-watering saps vitality and is one of the most common plant assassins, so learning to avoid it is worth the small effort. Plants make and store their own energy source – photosynthate - (sugar/glucose). Functioning roots need energy to drive their metabolic processes, and in order to get it, they use oxygen to burn (oxidize) their food. From this, we can see that terrestrial plants need plenty of air (oxygen) in the soil to drive root function. Many off-the-shelf soils hold too much water and not enough air to support the kind of root health most growers would like to see; and, a healthy root system is a prerequisite to a healthy plant.

Watering in small sips leads to avoid over-watering leads to a residual build-up of dissolved solids (salts) in the soil from tapwater and fertilizer solutions, which limits a plant's ability to absorb water – so watering in sips simply moves us to the other horn of a dilemma. It creates another problem that requires resolution. Better, would be to simply adopt a soil that drains well enough to allow watering to beyond the saturation point, so we're flushing the soil of accumulating dissolved solids whenever we water; this, w/o the plant being forced to pay a tax in the form of reduced vitality, due to prolong periods of soil saturation. Sometimes, though, that's not a course we can immediately steer, which makes controlling how often we water a very important factor.

In many cases, we can judge whether or not a planting needs watering by hefting the pot. This is especially true if the pot is made from light material, like plastic, but doesn't work (as) well when the pot is made from heavier material, like clay, or when the size/weight of the pot precludes grabbing it with one hand to judge its weight and gauge the need for water.

Fingers stuck an inch or two into the soil work ok for shallow pots, but not for deep pots. Deep pots might have 3 or more inches of soil that feels totally dry, while the lower several inches of the soil is 100% saturated. Obviously, the lack of oxygen in the root zone situation can wreak havoc with root health and cause the loss of a very notable measure of your plant's potential. Inexpensive watering meters don't even measure moisture levels, they measure electrical conductivity. Clean the tip and insert it into a cup of distilled water and witness the fact it reads 'DRY'.

One of the most reliable methods of checking a planting's need for water is using a 'tell'. You can use a bamboo skewer in a pinch, but a wooden dowel rod of about 5/16” (75-85mm) would work better. They usually come 48” (120cm) long and can usually be cut in half and serve as a pair. Sharpen all 4 ends in a pencil sharpener and slightly blunt the tip so it's about the diameter of the head on a straight pin. Push the wooden tell deep into the soil. Don't worry, it won't harm the root system. If the plant is quite root-bound, you might need to try several places until you find one where you can push it all the way to the pot's bottom. Leave it a few seconds, then withdraw it and inspect the tip for moisture. For most plantings, withhold water until the tell comes out dry or nearly so. If you see signs of wilting, adjust the interval between waterings so drought stress isn't a recurring issue.

Choosing an Appropriate Size Container

How large a container ‘can’ or ‘should’ be, depends on the relationship between the mass of the plant material you are working with and your choice of grow media. We often concern ourselves with "over-potting" (using a container that is too large), but "over-potting" is a term that arises from a lack of a basic understanding about the relationship we will look at, which logically determines appropriate container size.

It's often repeated that you should only move up one container size when "potting-up". The reasoning is, that when potting up to a container more than one size larger, the medium will remain wet too long and potentially cause root rot issues, or at a minimum, limited root function. In reality, it is the size/mass of the plant material you are working with, and the physical properties of the medium you choose that determines both the upper & lower limits of appropriate container size - not a formulaic upward progression of container sizes. In many cases, after root pruning a plant, it may even be appropriate to step down a container size or two, but as you will see, that also depends on the physical properties of the medium you choose. It's not uncommon for me, after a repot/root-pruning to pot in containers as small as 1/5 the size as that which the plant had been growing in prior to the work.

Plants grown in ‘slow’ (slow-draining/water-retentive) media need to be grown in containers with smaller volumes so the plant can use water quickly, allowing air to return to the medium before root issues more serious than impaired root function/metabolism become a limiting factor. We know that the anaerobic (airless) conditions that accompany soggy media quickly kill fine roots and impair root function/metabolism. We also know smaller medium volumes and the root constriction that accompany them cause plants to both extend branches and gain o/a mass much more slowly - a bane if rapid growth is the goal - a boon if growth restriction and a compact plant are what you have your sights set on.

Conversely, rampant growth can be had by growing in very large containers and in very fast (draining) media where frequent watering and fertilizing is required - so it's not that plants rebel at being potted into very large containers per se, but rather, they rebel at being potted into very large containers in a medium too slow and water-retentive. This is a key point.

We know there is an inverse relationship between media particle size and the height of the perched water table (PWT) in containers. A PWT is water that fills spaces between soil particles and defies gravity by refusing to leave the pot. As particle size increases, the height of the PWT decreases, until at about a particle size of just under 1/8 inch, media will no longer hold perched water. If there is no perched water, the medium is ALWAYS well aerated, even when it is at container capacity (fully saturated).

So, if you aim for a medium (like the gritty mix) composed primarily of particles larger than 1/16", there is no upper limit to container size, other than what you can practically manage. The lower size limit will be determined by the medium volume's ability to allow room for roots to ’run’ and to furnish water enough to sustain the plant between irrigations. Bearing heavily on this ability is the ratio of fine roots to coarse roots. It takes a minimum amount of fine rootage to support the canopy under high water demand. If the container is full of large roots, there may not be room for a sufficient volume of the fine roots that do all the water/nutrient delivery work, and the coarse roots, too. You can grow a very large plant in a very small container if the roots have been well managed and the lion's share of the rootage is fine. You can also grow very small plants, even seedlings, in seemingly inordinately large containers if the medium is fast (free-draining and well-aerated) enough that it holds no, or very little perched water.

I have just offered clear illustration why the oft repeated advice to ‘resist potting up more than one pot size at a time’, only applies when using heavy, water-retentive media. Well-aerated media are not bound by the same restrictions. As the ht and volume of the perched water table are reduced, the potential for negative effects associated with over-potting are diminished in a direct relationship with the reduction - up to the point at which the soil holds no (or an insignificant amount) of perched water and over-potting pretty much becomes a non-issue.

Questions?

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Comments (24)

Lemon Lime Orange Zone 6a
3 years ago
last modified: 3 years ago
Citrus has been grown in terracotta for thousands of years because it works well, is very forgiving and dries out extremely fast. I have a 7 foot Hamlin Orange tree in a Pennington 22 in. heavy rimmed extra large terracotta clay pot from Home Depot and I have to water it almost every day in the summer in zone 6.

Bagged potting soils usually have an electrical conductivity of around 1.85-2.15 EC. This is important to know because citrus species and their fruit yield is generally reduced at soil electrical conductivity (EC) above 1.4 ds/m. Salinity, not only reduces growth and yield due to the osmotic potential effect, but for the same reasoning salinity delays and depresses emergence, reduces shoot and root bio-masses.

When you re-pot with potting soil which already has EC too high and add more fertilizer and iron you are pushing the salinity way too high and the the plant than can't manage water or nutrient uptake.

You definitely don't need iron chelate as the potting soil is going to be slightly below 7 pH which is perfect for iron availability and the citrus fertilizer already has iron in it.

Potting media has a maximum moisture content (also know as maximum humidity) which is the amount of water the media can hold. You want no higher than 60%. Some potting soils may be 70% which is too high. You can use cactus soil but it will drain too fast in terracotta. Any of the FoxFarm potting soils work great and can be purchased at any hydroponics store. You want to cycle between 40-60% moisture.

Clean your clippers before pruning. Yes cut the long branch so it is even with the other branches. No need to seal anything.

The best way to measure EC at home is with a Blue Lab Pulse Meter. If you can't measure your potting media you can't manage it.
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tapla (mid-Michigan, USDA z5b-6a)
3 years ago
last modified: 3 years ago
Bagged potting soils usually have an electrical conductivity of around 1.85-2.15 EC. This is important to know because citrus species and their fruit yield is generally reduced at soil electrical conductivity (EC) above 1.4 ds/m. EC/TDS are in constant flux, changing with temperature, pH, moisture levels, and the level of all dissolved solids, so it can't be said that potting media are usually in any specific range.

Salinity, not only reduces growth and yield due to the osmotic potential effect, but for the same reasoning salinity delays and depresses emergence, reduces shoot and root bio-masses. If fertilizer or nutrients were actually "plant food", we could say that a plant's diet consists of salts. So in order for a plant to grow normally, a certain level of salinity in the soil solution would be essential to a (terrestrial) plant's viability. It cannot be said that salinity "reduces growth and yield due to the osmotic potential effect, but for the same reasoning salinity delays and depresses emergence, reduces shoot and root bio-masses", though it can be said that 'excess'or insufficient' salinity can have the effects mentioned.

You definitely don't need iron chelate as the potting soil is going to be slightly below 7 pH which is perfect for iron availability and the citrus fertilizer already has iron in it. Fe (iron) is most available at much lower pH levels (4.0-4.5), but because aluminum becomes available and potentially toxic at pH levels that low, a pH of about 5.4-6 is a much better range for Fe uptake.

Too, Fe uptake isn't just affected by pH. High levels of several nutrients (Cu, Zn, Mn, Ca, and particularly P) can individually or collectively limit uptake of Fe.

Al
Lemon Lime Orange Zone 6a
3 years ago
5.8 to 6.5 pH is ideal for citrus. Iron is a micro nutrient and is plentiful in Citrus fertilizers. If you can’t measure it you can’t monitor it. Anything in excess can be problem.
tapla (mid-Michigan, USDA z5b-6a)
3 years ago
last modified: 3 years ago
We're talking about containerized trees. the "ideal" pH for any plant in a pot is very near a full number lower for container media than for trees planted in the ground.

I didn't say Fe (iron) is not a micro-nutrient, it is, but that it is present in a fertilizer being applied or in the grow medium at 'normally' adequate levels does not ensure an adequate absorption rate. For example, if there is an adequate level of Fe in the grow medium or even in the soil solution, using a bloom booster fertilizer (high in phosphorous) can cause an antagonistic deficiency of Fe, which limits Fe uptake. High pH can also make Fe unavailable. In such cases, an Fe chelate like Sprint 138, an Fe chelate formulated for high pH applications can handily resolve the issue. I use it regularly in summer but choose to acidify my irrigation water in winter (to offset the high pH causing difficulty with Fe uptake) for plants under lights because I have a problem with bicarbonate build-up; this, due to the fact I'm unable to flush the grow medium as thoroughly in winter as in summer when all plants are outdoors and watered with a garden hose and water break. The only monitoring device I need is my eyes, yet the hundreds (thousands?) of plants/plantings I've posted over the years show plants growing at a very high level of vitality.

Potting media has a maximum moisture content (also know as maximum humidity) which is the amount of water the media can hold. The term you're looking for is 'container capacity' which is a measure of the level of water retention after a container has been thoroughly saturated and at the point where drainage has just stopped. For agricultural applications, the term is 'field capacity'.

You want no higher than 60%. Some potting soils may be 70% which is too high. 60% of what? Total porosity? Air porosity at container capacity? Most organically based container media used in the greenhouse industry have 75-85% total porosity. Also, % measurements of air porosity and water retention are not fixed values. In order for %s of air and water relationships in the subsurface environment to be useful, they must be container specific as the % of air porosity and water retention change with the ht, shape, and volume of the container. The containers below are all filled (to the rim) with the same grow medium. The shaded part represents a perched water table of consistent ht, at container capacity. It can be very easily seen the % air porosity is much greater than the % of air porosity in the squat or bonsai pot.

You can use cactus soil but it will drain too fast in terracotta. That a bag of grow medium says 'cactus soil' on the outside has little to do with what's inside the bag. Very few cactus soils work as well for cacti and succulents as they could if made a bit differently. In almost all cases, 'fast' drainage and more complete drainage are your friends. Yes, it will force the grower to water more frequently, but from the plant's perspective, that is a blessing. Whether or not a grow medium deserves to be called 'good' depends on whether or not it can be watered to beyond the point of saturation and not remain wet, in the container being used, so long that it seriously limits root function or damages root health.

Any of the FoxFarm potting soils work great and can be purchased at any hydroponics store. Works great compared to what? Again, this is a highly subjective opinion that depends on the ability of the medium to hold enough air and dry down fast enough to avoid root issues in the container being used.

Al
Lemon Lime Orange Zone 6a
3 years ago
last modified: 3 years ago
Shane, I have left you some useful links below. I have no clue why people post advice on the citrus forum when they clear as day have never grown citrus before.

pH .....https://citrusindustry.net/2022/05/18/keeping-soil-ph-at-the-optimal-level/

(EC) above 1.4 ds/m (on page 27).....https://www.haifa-group.com/files/Guides/Citrus.pdf

You can't measure it you can't monitor it .......https://commonsensecitrus.com/

https://bluelab.com/amer/bluelab-pulse-multimedia-ec-mc-meter

"Haifa Group, founded in 1966, develops, produces, and supplies a wide range of specialty fertilizers in more than 100 countries. Haifa Group includes 17 subsidiaries worldwide and production facilities in Israel, France, and Canada.

"Ian Tolley is a specialist and global expert in seed production, seedling production, orchard planning establishment, and management. He was awarded an OAM, Medal of the Order of Australia, for his lifelong services to the development of the Australian citrus industry. Ian is also a Fellow of the Winston Churchill Memorial Trust"

"Citrus Industry magazine delivers key information to citrus growers, production managers, and other citrus business people. It provides the most current information available to help owners and producers successfully grow and market their fruit."

"Bluelab has made the tools that help growers achieve exceptional crop and yield. Based in New Zealand, our team is international, with offices in the United States and in Europe. Our products and our support are second to none and, above all, our goal is to help growers unlock their crop’s full potential, where each plant experiences thriving growth and optimal health."
tapla (mid-Michigan, USDA z5b-6a)
3 years ago

Optimal pH levels ^^^ for mineral soils (growing in the ground).

Optimal pH levels ^^^ for soilless media (growing in containers). You can see they vary by almost a full number which would mean that due to the logarithmic nature of how pH is measured, container grown plants in soilless media would need to be grown under conditions nearly 10X as acidic as plants growing in situ. You can't bring the orchard to containers and expect methods to be interchangeable.

The rest of what you offered immediately above doesn't have anything at all to do with what I said about errors made re Fe availability, moisture levels and porosity in container media, or anything else I mentioned.

FWIW, I have grown citrus without issues, finding them no more difficult than the other genera/species of woody material I grow, but my focus is primarily on bonsai. Since most citrus species generally make poor bonsai candidates for bonsai because of their growth habits, they don't hold much interest for me; however, one doesn't need to be the bus driver to know what makes the wheels go around and around.

Al
Silica
3 years ago
last modified: 3 years ago
Lemon Lime Orange, as you have found out by this post some people are "know" it alls.
Lemon Lime Orange Zone 6a
3 years ago
Silica you have made some excellent contributions to this forum over the years.
Lemon Lime Orange Zone 6a
3 years ago
Lemon Lime Orange Zone 6a
3 years ago
last modified: 3 years ago

Hamlin Orange Tree.
Lemon Lime Orange Zone 6a
3 years ago
The average EC is currently 1.6 and still too high. Aiming for 1.2 to 1.4.
tapla (mid-Michigan, USDA z5b-6a)
3 years ago
In conventional container culture, EC is always in constant flux because it's influenced by so many varying factors - water source, watering habits, time elapsed since the planting was last watered (big one), temperature, pH, media components, type of fertilizer used and rate at which it's applied, TDS level, even the age of roots affect EC.

If a grower waters on day one of a typically 5 day interval between waterings, by the 5th day the EC level could be 3-4 times higher than on the day it was first watered, with no other changes except those caused by the medium drying down, thus - constant flux. Chasing a stable pH value is another exercise in futility for container growers who lack the equipment (water injection set-up) and chemicals (assorted acids and bases) to monitor and change pH on a day to day basis.

Al
Silica
3 years ago
Nice looking container tree. How old is the tree?
Lemon Lime Orange Zone 6a
3 years ago
Thank you Silica. I am not sure, I think it is about 5 years old.
Lemon Lime Orange Zone 6a
3 years ago
I can view years of data, up to a maximum of around 2000 measurements, and include notes and photographs on every measurement. I can review thousands of EC, temperature, and moisture readings. I can calibrate for different media and get accurate results with a high degree of certainty.
tapla (mid-Michigan, USDA z5b-6a)
3 years ago
last modified: 3 years ago
..... and?

I'm not trying to be mean, and I haven't said anything demeaning. I read what you said initially, and felt it had enough questionable information in it that a different POV might be beneficial, so I provided one and now we've both expressed our opinions. What you've said since doesn't have anything to do with my observations, and that's fine, I don't mind one way or the other. Hopefully, others have enough information by now to make their own decisions. Peace out.

Al
Alex [Zone 6a Lithuania.]
3 years ago
last modified: 3 years ago
tab. Optimal pH levels ^^^ for soilless media - this is true for hydroponics.

Why did you write - (growing in containers)?

Do you think Shane Allen has soil ^^^ for soilless media?
seasiderooftop
3 years ago
@tapla (mid-Michigan, USDA z5b-6a) thank you for that information about pH and nutrient availability in pots vs in the ground, that's very useful info!

I do wonder along the lines of Alex's questions above, when you say soilless does that mean in a medium like the gritty mix or the 5-1-1, or is the lower optimal pH also true when using the bagged potting "soils" available in commerce?
tapla (mid-Michigan, USDA z5b-6a)
3 years ago
last modified: 3 years ago
@seasiderooftop - Any medium formulated specifically for growing in containers that doesn't involve mineral soil (topsoil) is a soilless media. The gritty mix as well as the 5:1:1 mix both soilless media. With nutrient availability being the topic, plants grown in any soilless medium will generally appreciate a pH about a full number lower than they would prefer in situ (where they naturally occur), so it would hold true for all media lacking mineral soil.

Growing in the ground is much different than growing in containers, so most of what goes on in the orchard changes if we want optimum results in containers. For starters, mineral soils are much harder to use for conventional container culture (growing in a pot) because their physical characteristics are not conducive to good root function/ health - they hold too much water and not enough air in containers. Many commercially prepared media are also too water retentive for best results, which is why so many try to put workarounds in place my amending these media so the can't hold such high volumes of water in a saturated layer of medium at the bottom of the pot.

@Alex [Zone 6a Lithuania.] - Optimal pH levels ^^^ for soilless media - this is true for hydroponics? As a general rule, a pH of 5.5-6.5 is considered ideal for hydroponic growing, but plants vary and have quirks that sometimes make it beneficial to adjust pH levels to suit a specific plant or its quirks. Example: Acid-loving plants have adapted to acid soils. Their need for calcium is still the same as any other plant, and their nutrient requirements do not differ from plants that thrive in alkaline soils. The problem for acid-loving plants is that they have not developed a method to 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 iron, which is tightly bound in alkaline soils, another reason why they thrive in low pH soils. This all pertains to the plants ability to handle nutrients, not to the actual nutrient needs of the plant.

Why did you write - (growing in containers)? I glanced through all I wrote upthread, but didn't catch where I said that. If you'll provide some context so I can see where/how I used it, I'll be glad to explain. Maybe you could c/p the paragraph in which it's found?

Do you think Shane Allen has soil for soilless media? He mentioned he is using a Dr. Earth product for cacti/succulents, so it would be a soilless medium.

If either of you have additional thoughts, don't hesitate to share.

Al
seasiderooftop
3 years ago
Thank you so much for the extra details @tapla (mid-Michigan, USDA z5b-6a)! I will take that into account when I repot my dwarf clementine tree later this year, and will try to get to a lower pH than before.
tapla (mid-Michigan, USDA z5b-6a)
3 years ago
last modified: 3 years ago
@seasiderooftop - You won't be able to reach and maintain a stable pH because so many variables affect pH levels. The same is true for EC which stands for electrical conductivity. Knowing how conductive the soil solution is is a fair indicator of the level of dissolved solids/ salts in the soil solution. The problem with relying on EC readings lies in the fact that the EC level can be in the preferred range, even though the ratio of salts (nutrients) in the soil solution is badly skewed, even to the degree the imbalance causes antagonistic deficiencies (too much of nutrient A causing a deficiency of nutrient B, and potentially others). Case in point: Calcium (Ca) and magnesium (Mg) are antagonists. The EC reading can be perfect even while there is 5X as much Mg as Ca, the reverse of what the ratio should be. So a perfect EC reading is useless unless one knows the ratio of nutrients in the medium. As long as the ratio of nutrients is correct and EC/TDS readings are appropriate, you're golden. So, if you are using a fast draining medium and are flushing the medium regularly and fertilizing with a fertilizer like Foliage-Pro 9-3-6, your chances of success are greater than when using a less appropriate fertilizer and struggling to maintain EC within a narrow range.

BTW - Foliage-Pro 9-3-6 is an acid-forming fertilizer that can lower media pH temporarily. This is because, as N sources, it contains ammonium at approx 40% along with 60% nitrate nitrogen. As soil organisms oxidize the nitrogen to nitrate, hydrogen ions are released, which makes the medium more acidic. The hydrogen released is the 'H' in p'H'.

Circling back to using a fast draining medium, flushing the medium regularly, and fertilizing with a fertilizer like Foliage-Pro 9-3-6. That combination gives you complete control of what your plant gets (in terms of nutrient load) and when it gets it. Flushing the soil as you water ensures the ratio of nutrients stays within an extremely narrow margin, so there is really no need to monitor pH or EC. For the most part, if you see yellowing between the veins it can usually be fixed by slightly acidifying your irrigation and fertilizer solution water. If that doesn't correct the issue, increase either the fertilizer solution concentration or the frequency with which you fertilize, but not both at once. If you see an o/a chlorotic (yellowish) appearance, it's most likely a case of not enough fertilizer, but it still wouldn't hurt to first try acidifying your irrigation/fertilizer solution water.

Al
Ken B Zone 7
3 years ago
Can you guys take your pissing contest somewhere else?
Lemon Lime Orange Zone 6a
3 years ago
Your being punked! If you understand and measure and monitor pH and EC than you can grow citrus in any media and destroy false narratives about potting soil. This is why the unusual overdrive on this thread. If the truth gets out the wheels fall off the bus.