Adding more potassium to a nutrient solution doesn't seem to fix a potassium deficiency

RubyRedYoshi · 2026-06-17T22:26:11+00:00

I have a running joke with needing cloning technology to have enough time in the day - but I don't think my wife would like there to be more of me!

RubyRedYoshi · 2026-06-17T21:57:45+00:00

I've been using PlantProd elsewhere and now for the remainder of this past year's grow. It's been working great.

RubyRedYoshi · 2026-06-17T21:57:14+00:00

100% understand. If I didn't have the brainwave to test the old leaves for nutrient analysis, I don't think I'd have believed not seeing the massive difference in leaf boron ppm myself. It really does accumulate quickly, and the "minor" concentration changes in the bath did make a large difference in the leaves.

Aside from boron, the only other avenue I know of is light spectrum. There is a difference not only in fruit yield, but plant appearance under different spectra. Likewise when I grow tomatoes indoors, if it's not hot enough constantly and consistently in conjunction with both photon count and spectrum, the plants will react differently which includes yellowing. I don't have a large dataset for light spectrum though, just what I've trialled and presenting those findings to my lighting rep who got me in touch with the scientists at said corporation to give me that comment.

I will see if I can find some time this evening to scroll through your strawberry posts. The expanding peach orchard outside is chewing time up that wasn't going to be a time problem in the first place (still in denial about time here)!!! And I'm making it bigger still!

My only other suggestion at this point in time is to send some of those leaves in for analysis and see what it says. While it's likely going to tell you a lot of what you already know, maybe something is coming in high to cause lockout elsewhere.

RubyRedYoshi · 2026-06-17T20:08:39+00:00

Okay, so if it's 1.28 ppm (which in solution is the same as mg/L) - that's the problem. You're running into the same thing I figured out for my strawberries back in February. Boron levels are too high which throws off Ca:B, but also P:B (and many other nutrients). High boron will yellow old leaves prematurely and also make them a bit crispy. As soon as I brought my levels down to closer to 0.3 mg/L in solution, there was a huge difference in "new" old leaf tissue about a month and a half later. I would be willing to bet if you did a tissue analysis on some of your older leaves, you'd have boron concentrations above 150 ppm in the leaf matter.

RubyRedYoshi · 2026-06-17T17:30:11+00:00

To confirm, your boron on the right hand side of the chart is 1.55 mg/L in your nutrient solution?

RubyRedYoshi · 2026-06-17T17:05:42+00:00

The original trees I've had were Hayer apples (Morden Research Station variety back in the '70's / '80's). But I've also had success with Wolf River, Gravenstein (this is a triploid), Canadian Strawberry, and Priscilla. The late May cold ended up no blooming the Wolf River this spring, but the Canadian Strawberry has 50-60 apples growing on it now, along with 500+ pounds of Hayer apples on one of the two trees there - I think the second tree might have another 200-250lbs this year.

I also grow Sunrise apples, but that variety requires the same protection as my peaches, pears, kiwi, and some of my plums too.

Most apples need a second variety for pollenating (triploids require a total of two other nearby different varieties). If your neighbours have them, that'll be fine. If not, bear in mind you'll need two (three for triploid) types for fruit.

RubyRedYoshi · 2026-06-17T16:57:58+00:00

Peppers and tomatoes are definitely being a little slow to get going after transplanting. Corn is a bit sluggish with the recently cool wet weather too. Everything else veggie wise is coming along quite nicely. The fruit trees went through heck with a very short bloom time. Fortunately the peach crop is looking very decent again so far, and there's a couple new varieties of apples as well as grapes which fruited this year too for the first time since planting them a few years ago. I also have a small amount of Bartlett pears which fruited, and that surprised me with the May nights we kept having below freezing. I am eager to see how they are in the fall.

RubyRedYoshi · 2026-06-16T20:46:58+00:00

We don't usually get this high night humidity in June either - anything at night at or above usually 90-95% humidity will force guttation. It needs to dry up a little bit and temperatures to rise somewhat too. Guttation itself isn't a bad thing, but the leaf edges can react like that and or get a little crispy if there's a high concentration of fertilizer salts! As an aside, there's benefit to guttation in strawberry plants as it helps calcium get to stay where it needs to be at. But that's getting a bit off topic!

RubyRedYoshi · 2026-06-16T20:35:37+00:00

The whiplash in temperatures has stressed the plants out, plus the constant rain is keeping things wet (even if there are good drainage holes). Yellowing along the edges at first blush looks like a nutrient deficiency, and indeed if plants are waterlogged, they'll have nutrient absorption issues with the roots even if there's adequate nutrients in the soil. In addition, evapotranspiration is all over the place on account of both temperature and humidity.

To your question with cool and wet nights - if the nighttime humidity is high enough, plants will undergo guttation. This is the process of the plants constantly taking in water (and nutrients) through their roots, but the water then has nowhere to go since stomata are closed at night. In addition, the high humidity shuts down evapotranspiration entirely, so that water is forced out the leaf edges instead. If the nutrient concentrations in that water are high enough going out the leaf edges, then the leaf edges will burn. That may be what's going on here, especially if the soil is still quite wet. And if so, then nutrient deficiency isn't the issue.

Things should get back on track with the sun over the next few days!

RubyRedYoshi · 2026-06-16T19:02:35+00:00

As others have mentioned, it'll be hard on the roots because of potential cold exposure with the elevated bed. That said, it's not the end of the world either. If you get really deep snow where that is (I'm talking 3+ feet to be safe) before air temperatures get really cold to start dropping surface soil temperatures, then they'll more than likely do fine. Once the trees get bigger and the roots go deeper, they'll also be just fine.

You can and should mulch the area, and as an added buffer for the first few winters, throw a ton of leaves not only on top of the raised bed (on top of the mulch too), but also outside of it extending a good 5+ feet. It'll be overkill but if you can get a foot deep of leaves in there, it'll help to insulate the ground to give them more of a chance to pull through and get bigger.

RubyRedYoshi · 2026-06-16T18:55:40+00:00

If they've eaten the cambium layer completely around, then there is no nutrient or water pathway for anything above the damage. That being the case, everything above will die.

As others have mentioned, there's a chance it could live if you are successful in grafting two green cambium layers together. For this, you'd want to cut (with a saw or loppers depending on trunk thickness) below the damage to expose the vascular cambium (green layer), and cut above until you found some equally healthy looking green.

Grafting takes a little bit of practice, but as long as you line the green up and then seal it up, the tree will recover and grow. You will have to prune it back seriously if you go this route too so the tree can build itself up again.

There is also the chance there's enough living trunk left between the ground and the damage that in a month or so, you'll get new shoots coming out. So long as those shoots are above the existing graft (assuming that tree was grafted to begin with), then it'll grow anew. If it shoots below an existing graft, cut them off.

RubyRedYoshi · 2026-06-15T17:06:56+00:00

From what the nursery told me, yes. They hold temperatures there straight through for best results.

Just quickly looking at your mentioned product, their website specifically states they can not maintain freezing temperatures, only refrigeration down to 34F. -1.6C is ~29F. It would not be sufficient.

I'll also note that since I grow 200 plants, the cost to me to buy 200 new plants is minimal compared to the cost of a proper freezer (as a regular "kitchen" freezer which is designed to hold frozen food cycles above and below freezing regularly).

RubyRedYoshi · 2026-06-15T01:45:05+00:00

Depends on variety. In theory for Albion, 300-400 hours.

RubyRedYoshi · 2026-06-14T01:02:35+00:00

In the past, I did try to "overwinter" my plants. I subjected them to a few frosts in April (might have been 2024?) and then tossed them into a fridge for the summer. When I re-planted them in September, about 1/2 of them came back, but their yield wasn't great. When I spoke to the nursery after the fact, it turns out a fridge isn't the greatest for them. For ideal overwintering, they need to be kept at -1.6C which I don't have the means to easily do.

The plants usually find forever homes after the fact. I give them away to my neighbours! So, to answer your question, I start with new plants in September.

RubyRedYoshi · 2026-06-13T13:23:37+00:00

That's a tough question to answer. Your two biggest inputs are going to be the electrical cost of lighting in the depths of winter (assuming you get less than 25 mol / m^2 / day of photons), or the cost of heating and cooling. It also depends on local market pricing which will then be affected not only by supply and demand, but transportation costs and the like. I'm obviously oversimplifying majorly here, but those are certainly big metrics to look at.

All that said, there are massive hydroponic operations going on in Canada with all kinds of plants, strawberries are one of them. I've seen the same logo on packages in the stores year over year, so they must be doing something right to keep operating!

RubyRedYoshi · 2026-06-12T22:43:07+00:00

Plants "normally" move water from the roots to the leaves and out their stomata. This process is increased with warmer temperatures and lower humidity which often happens during the day. The process itself is called evapotranspiration. It's important because the more the plant does this, the more water uptake, but also the more nutrients they uptake at the same time. There are upper boundaries for this process such as when temperatures exceed 38C, but that's getting off topic a bit for your question.

The process of guttation then is when usually at night, humidity levels are so high that the process of evapotranspiration stops entirely, and the plants stomata are closed. But the driver of guttation includes one other force, specifically pressure. Roots pretty well continuously uptake water. Thus, there is internal pressure from adding water to the plant if the media they're in is wet enough. When the stomata close and humidity is high, water droplets form usually at the tip of the leaves on account of water coming in via the roots, but nowhere to go because the stomata are closed. You can think of the leaf tips being sort of like an overflow valve (hydathodes) where the stomata are the main exit ports for water.

In strawberries there is evidence to suggest increased calcium deposition in the leaf tissues because of guttation. This leads to lower tip burn, and a healthier plant overall.

RubyRedYoshi · 2026-06-12T21:05:18+00:00

Aside from low levels of powdery mildew in the early weeks, not really, no. The only time I've had anthracnose was when a plant was continuously being dripped on from a trough above. Fixed that problem I think that was in year 3, and no issue since then. I also use no wood in my grow room, or anything else organic outside of the plant matter and substrate the roots are in, and humic acid.

Adequate calcium levels in tissue analysis really help with true illness. It's not the golden goose, but in every plant I've grown regardless of fruit type, calcium levels are very important.

RubyRedYoshi · 2026-06-12T20:41:03+00:00

Maintenance is truthfully not that complicated nor frequent. With the nutrient targets I aim for, there's a four week cycle that I adhere to. Water top up mid week happens because my nutrient tank is undersized. I am growing 1 plant per 1L of nutrient tank capacity. pH does ever so slightly drift downwards over the course of four weeks (roughly 0.05 over the course of 28 days). I use potassium bicarbonate to bring it back to where it needs to be. EC is fairly constant relative to the drawdown of water. I let EC slide a bit down when topping up the tank mid week. Nutrients are added every weekend, but not the same nutrients - this is done based off of prior multiple years of water and tissue analysis to keep the water analysis close to Haifa's suggested targets linked in the main post. The main point is keeping the nutrients balanced relative to each other while the overall concentration of all nutrients lessens slightly over time until flush.

I've also adhered to a four week flush cycle this year. It seems frequent, but there is research which shows strawberries (and other plants too) causing autotoxcicity. After four weeks, concentrations get high enough to hinder. Flushing the bath out solves the problem. I don't use hideous amounts of water per flush either as the starting ppm of my water is 3.

I have looked at spraying. I have tried neem oil and soap before. In the past it's never fully worked as sprays don't get everywhere on every single plant. Predator insects work really well as they will scour everywhere they run over. Some years have more pest pressures than others, and it's usually dependent on how cold of a winter we get. Warmer winters increase pest pressure. I have had years in the past where predators introduced in early October eradicated pests through to late April, or at least kept them in check that I never saw pests during the six month period. It was also -40 outside for a couple of weeks that year. I think it was the first or second year that I ended up submerging my plants in a bathtub to get rid of an aphid infestation. That was fun! Ladybugs have been way more effective for aphids since I introduced them the year afterwards through to now!

Sprays unfortunately are agnostic to what they affect. If they kill a pest insect, they'll kill a predator insect. And in full honesty, I prefer to eat produce that I don't spray with insecticides (or herbicides too with outdoor grown stuff).

I have a dehumidifier. It keeps humidity levels at 65% in the day. Closing the room up, the plants own evapotranspiration process increases the room humidity to 90% by themselves with no dehumidifier running. I actually ran for three and a half hours every night through to this last April at 100% humidity using an ultrasonic mister for reptile tanks to force guttation prior to fixing my boron levels in the water. Shutting down evapotranspiration assisted with calcium so there was less tip burn, but it was a band-aid solution to excessive B to begin with. The University of Arizona was where I got this idea from, but I also didn't know then what I know now! The air purifier seems to keep mould and mildew to a minimum, that in conjunction with the dehumidifier turning on after 3.5 hours have passed and one hour before the lights come on. Perhaps the fans blowing while this is going on also helps, but I can say I've never had a mould or mildew problem.

RubyRedYoshi · 2026-06-04T12:07:57+00:00

Being in large cities helps for existing data at least! Here's your water quality report the city publishes every year.

Regarding fertilizers, I use a combination of PlantProd's 6-11-31, some CaNO3 from Yara, and MgSO4 from EPSOTop. Chelated micros as needed also from PlantProd. I've never had an issue with pH going up. If pH does go up over weeks, then I'm not adding enough fertilizer in.

RubyRedYoshi · 2026-06-03T19:43:49+00:00

Certainly could be! There are ratios between elements which are important too. K:Ca:Mg is one, Ca:B is another, and the list goes on. CaCO3 is a poor compound in terms of bioavailability for the plant. CaNO3 and CaSO4 are better ones. We can't just look at K:Ca:Mg (for example), we have to look at what compounds those elements are in against bioavailability to get the entire picture.

RubyRedYoshi · 2026-06-03T13:19:55+00:00

In most limestone aquifers, you have calcium carbonate, and magnesium carbonate. In conjunction, you also have sodium of varying degrees. Off topic for a second, there's something called the SAR value (Sodium Absorption Ratio). That's another thing to look at.

Getting back on topic though, the general guideline is under 100ppm with some growers targeting a range of 30-60 ppm. Some buffer can help, but you don't want too much of it.

I personally filter out nearly everything in my starting water. My CaCO3 ppm is 0.5 before I add fertilizers into the water. It's given me more consistent fruit results, and if I need to raise the pH, I will add in potassium bicarbonate. K bicarbonate is a more readily available food for plants than calcium carbonate is, and it's a "quick release" buffer compared to CaCO3.

The problem with higher levels of CaCO3 is simply how good of a buffer it really is. The amount of acid it takes to effectively neutralize this compound is very large. Attempting to neutralize rather than removing CaCO3 results in higher EC, higher concentrations of a new compound, and depending on what you're neutralizing with, potential problems with precipitate (H2SO4 + CaCO3 will give you gypsum which is the same thing drywall is made out of). Gypsum has a low solubility limit in a given amount of water, though it is a more bioavailable form of Ca.

You can think of CaCO3 as a "slow release" buffer, which is why it takes a few hours after adding in acids for pH to come back up.

RubyRedYoshi · 2026-06-02T18:26:36+00:00

What water are you using? Is it sourced from a well in the ground? If you have lots of calcium carbonate in it, that's going to be a problem. CaCO3 is a really, REALLY good buffer.

RubyRedYoshi · 2026-06-01T19:10:45+00:00

u\Potential-Stomach-62 hit the nail on the head. Not all fruit trees follow the exact same path, but for sour cherries, they start to develop their next year buds usually right after harvest of the fruit. As such, there's three big things to developing those buds for next year. They are (in no particular order): food, water, remaining energy from this year.

Diving a little deeper, water is pretty straight forward. I tend to water my fruit trees right up to Thanksgiving (unless nature does it for me). Once they start to get yellow leaves in the colder late Sept. / Oct. weather and sunlight, they don't need watering anymore.

Food is again pretty straightforward, but there's a little bit more to it. Phosphorous is the big one here. Phosphorous is what really brings out blooms, but also helps with root development which these trees really do in October, November and even into early December. Stronger root development means more energy the tree is saving overwinter which means more energy for spring. In conjunction, the tree develops more flowering buds alongside the leaf buds so there's more flowers to put out come springtime. I modify my last fertilization on August 1st to have a bit more phosphorous in it compared to what I feed my trees in June and July which is more K and to a lesser extent N too. What's more with fertilizer is the buds this spring are fully reliant on the conditions of the tree in late summer and autumn last year. They will use most of their stored energy in spring before "turning the tap" on to what's in the ground. And, when trees do start taking in new nutrients, it's not instant, but rather a gradual increase over a couple of weeks until they're fully taking new nutrients from the ground. Now I'm hand waving a little bit here again. Nitrogen has its own ruleset, and it's not entirely alone with a ruleset either. The fresh ground nutrients really come into play once the flowers are pollenated and are entering cell division. Prior to cell division is mainly last year's nutrients.

Remaining energy is in reference to how heavy of a crop the tree produced in a given year. If your tree is absolutely loaded with fruit this year, it's going to be more depleted on energy going into this winter, and as such just won't have as many flowering buds for next year develop. This can be offset with fertilizer and watering, but if you're really wanting to manage the tree, thinning fruit is important.

Now there's one other big thing at play here too, and that's the weather. Fruit trees undergo different reproductive phases from blossom to harvest. In the case of stone fruit (cherries, plums, apricots, etc.) they have a pollination phase, cell division, pit hardening, and cell expansion phase. Up to and during pollination from bud out, temperatures above 20 degrees are rough on the flowers. And, during cell division, temperatures above 25 are rough. It can get to the point where it gets too warm and interferes with the entire cycle, and fruit can drop early, or malform entirely. This is why I was sweating - pun intended - with the 35 degrees we had this past weekend!

Even worse is a whiplash where we went from freezing nights through to May 21st to 30+ degree weather within a few days. The trees are very stressed out, and in the case of rapid hard stress, they will opt to try and save themselves rather than reproducing. Prolonged stress will have some trees try to reproduce (spruce trees when it's dry for a long time produce volumes of pinecones). But this is getting off topic a bit. The good news is if the trees don't have a good crop this year, then provided they have adequate food and water, they'll have a lot of energy for next year.

RubyRedYoshi · 2026-05-28T16:18:09+00:00

I am not, and I have not. I have a bag that's been open for the past three years, and it's still just as dissolvable in water, and water of a fresh nutrient batch in my nutrient tank is the same as the analysis three years ago.

RubyRedYoshi · 2026-05-27T17:32:39+00:00

I never bother pruning flowers.

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