Yellowing areas on new growth

[DTOM420]

I decided to try some GH Armour Si and some FoxFarm Kelp You Kelp Me to my outdoor plants in 10 gallon bags. So I added the Armour Si at 1/2 strength and I added the Kelp at what I thought was 1/2 strength to hard well water pH’d to 6.3. Kelp bottle said 1-2 teaspoons per gallon of water. I added 1 teaspoon. Today I found their feeding schedule and THAT says to start with 1/4 teaspoon! Ugh! Today, my plants have this kinda patchy yellowing. In fairness, they may have had the start of this already, though. I saw some lightening a couple days ago but couldn’t get an effective picture. Today, though, it’s very pronounced and easy to see in a picture.

They’ve grown noticeably since yesterday but I don’t like the looks of this. I checked leaves with a loop and I dont see any bugs. I sprayed them with some neem just in case. Last week they got a spray of FoxFarm insecticide. I water every 2-3 days and the 10 gallon bags get 1 gallon of water and the 15 gallon bag gets 1.5 gallons of water. The soil is never bone dry but it’s sure dryer than it is when it comes out of a new bag of soil before I water. Sure would like to know what this is.

 

[DTOM420]

Calling @Waira for some help! Lol. You need a symbol we can project into the sky like the Batman signal. Lol!

FWIW - it’s been very hot here. Over 100°F/38°C. Our overnight lows have been 77°F/25°C and very low humidity. I had read that the silica and the kelp would help with the heat.

Calling @912GreenSkell

 

[Rev. Green Genes]

kelp would help with micronutes, it looks like early iron or micro def. When iron is involved I always check pH first, and add kelp. If that is enough great, if not get azomite to add in too.

 

[Waira]

.... looks like a pH issue, maybe too high, driven up by those last inputs; Si supp's for sure raise pH! Some even use it for that very purpose; not sure if the kelp pH is a factor, that'd have to be tested in plain water under dilution... Looks like maybe Fe or Zn defc. getting induced here, and that weather is NOT helping... that's making a real shit-show for transpiration, water stressing the plant, moist soil aside... it's a vapor pressure deficit issue (read up on this in the Reference section here), meaning the T and RH5 are really screwing with the flow of water and nutes from the roots to leaves... when it gets bad, the stomata shut, which brings the flow of things to a near halt,... You need to check that in-pot pH too if you can,...most of the micronutes family are immobile within the plant and lock out fast if the soil pH gets to 7.0,... that's why they show on newest growth first and worst typically....
As for a fix, getting the T and RH% better is key, pending what the in-pot pH is,... I can't say if this is a pH lockout, simple lack of, or all caused by the nasty env, conditions, or a mix of them,... so tackle what you can to eliminate causes,... I recommend the Accurate 8 soil pH probe for in-pot testing ........ Oh, your water source, pH and if you have it EC/TDS reading? Hard water may contribute to this by raising pH over time,...

 

[DTOM420]

.... looks like a pH issue, maybe too high, driven up by those last inputs; Si supp's for sure raise pH! Some even use it for that very purpose; not sure if the kelp pH is a factor, that'd have to be tested in plain water under dilution... Looks like maybe Fe or Zn defc. getting induced here, and that weather is NOT helping... that's making a real shit-show for transpiration, water stressing the plant, moist soil aside... it's a vapor pressure deficit issue (read up on this in the Reference section here), meaning the T and RH5 are really screwing with the flow of water and nutes from the roots to leaves... when it gets bad, the stomata shut, which brings the flow of things to a near halt,... You need to check that in-pot pH too if you can,...most of the micronutes family are immobile within the plant and lock out fast if the soil pH gets to 7.0,... that's why they show on newest growth first and worst typically....
As for a fix, getting the T and RH% better is key, pending what the in-pot pH is,... I can't say if this is a pH lockout, simple lack of, or all caused by the nasty env, conditions, or a mix of them,... so tackle what you can to eliminate causes,... I recommend the Accurate 8 soil pH probe for in-pot testing ........ Oh, your water source, pH and if you have it EC/TDS reading? Hard water may contribute to this by raising pH over time,...

@Waira Thanks! On your suggestion, I ordered an Accurate 8 meter that’ll be here on Tuesday. I’ll look for that article you referenced. Thanks for heading me in that direction because I only understood about 1/2 of what you said. lol! Yeah, our summers are pretty brutal but where there’s a will there’s a way; and there’s plenty of guerilla commercial grows not too far from here, with the same climate. But, I’m finding that using some judicious partial shading at the hottest part of the day seems to help.

Before I heard back, I went ahead and watered with pH’d (6.2) well water and the problem, whatever it was seems to be going away. The well water here has a hardness if 6 grains per gallon which is only slightly hard. However, there are a lot of other (besides the calcium and magnesium) dissolved solids in the water. It’ll vary between 925 and 1050 on any given day. And it is consistently 7.7pH. I’m trying to find a way to deal with it but I really want to use the automated drip system I’ve been using in my vegetable and flower garden. If I pH it, which is what I’ve been doing, it’s very labor intensive. Especially for the large outdoor garden I have planned and have been working on for next spring. Lots of sweat, time and €€€ invested already. Filtering it is a whole other can of worms since my drip system requires pressure. If only I could figure out a way to automate the pH control of a 100 gallon outdoor reservoir and then pressurize the output - all on a 12v system - I’d be golden! Lol. I’m not clever enough though. Not yet anyway.

I could hook up a RO filter outdoor to the water line but those systems rob the pressure and work so slowly that you’d have to RO the water into a holding tank; then, you’d have to create the pressure to push it through the drip system that needs at least 25psi water pressure. If I didn’t have to keep my purposes on the down-low, I might be able to ask around and get the help to invent a system. Unfortunately, everything related to growing here must be kept top-secret.

My hope was to get the soil on the acidic end of tolerable to help buffer the alkaline water and end up with proper nutrient uptake. I’ve done well with vegetables and our flower/plant gardens and our well water; but this darn weed is so much more tempermental than tomato’s, squash and blooming shrubs! Lol. I’m definitely looking for strains that are less picky and that can deal with the climate. That’s one reason I’ve been talking to Spanish breeders. The climate is very similar to southern Spain and Morocco. ....and might even be one of those. Lol.

I’ll let you know what I come up with once I get the probe on Tuesday.

 

[Waira]

:smoking: Cheers DT... huh, low hardness but high ppm still,.. any idea WTF is in the water besides the Ca/Mg carbonate? Is it full of Fe, or micro particulates,...? Something besides the calcium hardness is making those large TDS numbers and driving the natural pH up like that,... So even if there's possible forms of micronutrients in there, the pH has altered the chemistry and rendered them unavailable for uptake,... many of the micronutes are metals, and lock out pretty fast as the pH goes to 7.0,... But all this is pending a reading of in-pot pH to see if this is a lockout, or a simple lack-of, and/or a consequence of the harsh weather as described above,... the unknown dissolved solids in there may potentially screw with other nutes as well, so try to find out exactly what's in there beside the usual mineral hardness,... it may come down to some sort of ion exchange filtration, like what's done for well water that loaded with Fe, rust basically!
Basically, VPD deals with how T and RH% affect the rate of transpiration (water evaporation, gas exchange) off from the leaves,.... as you know T and RH% are closely linked; extremes cause problems with this... low RH%/high T makes the rate go nuts until the plant shuts off the stomata opening to prevent catastrophic water loss,.... high RH% makes it difficult for water to evaporate since the air is so loaded already, thus stalling out the transpiration,... think of that flow of water and nutes from the roots up and out through the leaves as being drawn out by the transpiration action, like a "negative" pressure,...

 

[DTOM420]

:smoking: Cheers DT... huh, low hardness but high ppm still,.. any idea WTF is in the water besides the Ca/Mg carbonate? Is it full of Fe, or micro particulates,...? Something besides the calcium hardness is making those large TDS numbers and driving the natural pH up like that,... So even if there's possible forms of micronutrients in there, the pH has altered the chemistry and rendered them unavailable for uptake,... many of the micronutes are metals, and lock out pretty fast as the pH goes to 7.0,... But all this is pending a reading of in-pot pH to see if this is a lockout, or a simple lack-of, and/or a consequence of the harsh weather as described above,... the unknown dissolved solids in there may potentially screw with other nutes as well, so try to find out exactly what's in there beside the usual mineral hardness,... it may come down to some sort of ion exchange filtration, like what's done for well water that loaded with Fe, rust basically!
Basically, VPD deals with how T and RH% affect the rate of transpiration (water evaporation, gas exchange) off from the leaves,.... as you know T and RH% are closely linked; extremes cause problems with this... low RH%/high T makes the rate go nuts until the plant shuts off the stomata opening to prevent catastrophic water loss,.... high RH% makes it difficult for water to evaporate since the air is so loaded already, thus stalling out the transpiration,... think of that flow of water and nutes from the roots up and out through the leaves as being drawn out by the transpiration action, like a "negative" pressure,...

I received my Accurate 8 yesterday. I’m getting kinda strange readings. I tested 2 pots that have completely different mixtures of soils (Happy Frog + OF and K9 + Happy Frog) from different product bags. One grow bag tested 5.6 and the other tested 5.4. This is after about 10 days of watering with nothing but well water pH’d down to ~6.2-6.3. A couple of plants have greener back up but one is even paler green than before. Although, she seems to have stabilized. Other plants, that are in partial shade don’t seem to be showing any ill effects at all. I’m kinda stumped.

We had 2 water treatment guys out recently and both came up with same results. Moderate hardness but lots of unknown dissolved solids in the water. I doubt it iron because it’s a brand new well, only 3 years old and the only iron that could be introduced is the well pipe and its new; so it can’t be degraded enough to be producing iron in water. Besides, the results are the same as they were 2 months after we drilled the well. That pH for the soil is too low, though; by a full point, isn’t it? Maybe I should try watering with straight water and see if the alkaline water with the acidic soil balances out?

This was sort of what I planned to test out, to see if there was a way to use my water - without adjusting pH - by having low pH and watering with a higher pH to result in a happy medium at 6.5. Is this possible? Any further advice @Waira ?

If the plants have plenty of water available to use, will the transpiration thing be an issue? What if I could rig up a mister over them? That’d raise humidity and help cool them, right?

 

[Waira]

... readings are fine DT, each pot is it's own "little world" and so pH is going to vary because of all the many influencing factors at work in each.... That said, the pH is a full point off, and is definitely locking out some nutes, but not micro's, they tend to stay readily available under acidic conditions,...

....... roger that on the testing,.. Fe and many other things can just as easily come from the rock strata the well is in, not the pipes themselves,.. but Fe is obvious by the staining it causes and metallic taste! ..... So, it's time to try a Ca-Mg supplement, and make sure it's at least in part carbonate based; it's the carbonate anion that's involved in pH buffering directly, not Ca/Mg... most these days have some nitrate based formulations, so be mindful of the N content and what else is in your nutes as you fertilize down the road,... 2-0-0, 1-0-0, is fine and easy to work with..... And yes to changing your input pH to 7.0+ for a few runs to see if you can bring the in-pot up to stable pH range,... flushing is another possibility, but may not need to go that far,... I'd water with pH adjusted water to at least 20% run-off volume to really flood the soil but not fully flush, and in the last pour, add a weak nute solution so you don't turn around and trigger other defc.'s form lack-of,.... if the soil is free draining, that's great, if not, set them on a short stack of newspaper with paper towels on top to help draw the excess water out faster by capillary action,... meantime, all this can be limited in net effect if the T/RH% stay in ranges that cause transpiration issues, and bottleneck their uptake.... a mister can help, but not so directly on the plant or you'll get mineral build-up from the rapid evaporation unless you use low ppm water,... window screen, shade cloth material can be used to cut the Sun down some which will help too,....