The necrotic spots are a sign of calcium deficiency, which is nearly always a symptom of a pH imbalance-nutrient lockout.
Ca deficiencies/toxicities generally present as necrotic areas that lie along the leaf veins and margins, though. These spots are very random, which is why I personally can't state unequivocally that calcium even has anything to do with it. Have you observed Ca deficiencies that show like that? Since I haven't, I can't say.
Try and get your soil's pH to around 6.5 and then begin using water acidified to about 6.0. As the water is slowly absorbed it will rise naturally thorough the ideal pH range, thus supplying your plants with whatever they may need.
This is where I must disagree with you. The OP is not growing in soil, he's growing in Sunshine Mix which is soilless (coco + peat, IIRC), which means it isn't mineralized
and that the desired pH range for feeding, etcetera, is far lower. Treating it more like coco is more in line, but since it's also got peat in it that is also a little different than coco. That said, I always keep feeds in the 5.8-6.2 range specifically for coco, I believe that Sunshine Mix performs better when feeding at levels closer to hydro pH ranges (mid to low 5's, IIRC).
From what ive read, and i could be wrong, but with organics the microbes will raise the ph when they poop? I'm using coco so shouldnt the ph be around 5.8-6.2? Im new to coco and organics coming from hydro and chems
Also im supplement my RO water that has 008ppm with cal mag to 140ppm
With organic SOIL. You're not growing in soil, there is little, if any, mineralization of the medium. That means a few things, for instance the coco in the medium locks onto calcium and magnesium. The peat drives pH down. In order for microbes and plants to mediate pH in the rhizosphere, though, they must have access to many different types of molecules and elements as well as the ions available in those compounds (God I hope to hell I've explained that accurately).
And you're using RO water which means that it has no ability whatsoever to resist pH shift. This is called "alkalinity". It also means that you *must* add minerals back to the feed, and with coco (I've never grown in Sunshine Mix, only organic soil, coco and pure perlite hempies. I DO have an extensive aquatic background, though, so I have a different understanding of water than most growers). You must add back at least Ca and Mg, and some micros wouldn't hurt, either. I must repeat, though, that what I'm seeing are not classic signs of Ca deficiency in coco, but that's not to say that that's not playing a role.
Ive asked around because people say the
General Organics line doesnt need to be PH adjusted. But i wont pour that acidic of a solution on my plants, and found that alot of people have their ph around 5-5.5 with the GO line and was advised to raise to that. I just watered 3 days ago for the first time since transplanting with ph 5.5, and have seen some improvement with the new growth.
pH MUST be measured, in this situation you're controlling every aspect of the environment and if you don't know your parameters you can't troubleshoot when problems arise. Obviously, there needs to be an adjustment in pH of the feed. I'm trying to remember if I've used any GO lines, and
Cal-Mag+ is the only thing I can think of that I've used. Wait... no. Anyway, I think if you can shoot for the low-to-mid 5 range you'll see improvement.
There is also a much more accurate way of determining media pH, but it would also require a more accurate method of measure than those $7 probes.
U cant accuratly ck ph with organics, those low readings are because theres no chems and salts, by adding a bunch of ph up your brewing poison, anytime you add raw organics ur ph will drop. If you take that 3.5 ph'd mix and bubble/brew it for 48hrs the ph will stabilize Perfectly.
But back to the problem at hand. Flush the shit outta them, set them in the corner, ignore them for a week, less is more. And hope for the best.
Hope this helps!
Solution pH can be measured very well and accurately with organics, it's EC (and therefore TDS/ppm) that can't be measured with any degree of accuracy because of the fact that many organic molecules simply do not conduct electricity. An experiment I've done myself but for other reasons that you can try is to try adding dolomitic lime to water that's been tested for pH and alkalinity (hardness) by testing for general and carbonate hardness parameters (a Tetra Laborette kit, about $25 at a local shop). First, test the original water, then dissolve some dolomitic lime into it. You'll find that it's driven up pH, general hardness, and carbonate hardness
significantly. The purer the water, the lower the pH of the original water, the more of the available minerals you'll be able to get into solution, too.
Going the opposite direction, you can add lemon juice, vinegar, or other acidic organic compounds to water of a high pH and accurately measure it as it's driven down and, if it's alkaline, climb back up.
I think I'm beginning to agree that a flush may be in order here, but since I haven't grown in Sunshine Mix I feel I can't speak accurately to how it should be handled. It is specifically the peat (etc? can't remember what else is in it!), the fact that it isn't pure coco you're working with here that I feel I can't speak in absolute or certain terms. If it were
Botanicare coco bricks (the 5kg bales) then we could maybe even grok even.
