Barely into that article and run into a glaring error so not sure how good the rest is. Claims that low K mimics low iron?! Not even close. Low iron starts as yellowing in new growth beginning at the petiole and working out towards the tips of the fingers. Low K starts in older fan leaves like low N, P, Zn and Mg as they are all mobile nutes and will be stolen and relocated to where they are needed in the grow tips. The rest are non-mobile so if it's not available in the root zone either from a lack or lockout new growth goes off.
"The symptoms of a potassium deficiency manifest very similarly to those of an iron deficiency. Leaf tips will start to turn brown or yellow and leaves may also start to curl. In cases that persist, leaves may start to appear burnt. Additionally, stems will begin to “stretch” and the plants will become unusually tall or long, but structurally weak. Left untreated, chlorotic blotches will appear on leaves, followed by necrosis."
Now this looks as described for low K.
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Low Fe is totally different. I recently had a serious excess that almost killed the garden. This little pic was like a photo of the bronze leaves with the spots. A good flush got most of it out but they are still suffering a bit 25 days into flower. Getting the hang of this organic growing stuff is gonna drive me back to hydro!
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Excess P is one of the most likely suspects when K is locked out and we all use way more P than we should because that's what's marketed to us. Pot needs way more K than P except right at the stretch it needs a bit more but still wants more K than P. That's why I use Big Bud instead of a P/K for a boost and have since it was invented. 0-15-35, 10%S, 20 aminos and a little citric and ascorbic acids. The original formula was 0-10-40 with 7%Mg instead of S but they tweaked it a few times before the latest version.
Too much P is also teh culprit in that 'chem' taste in overfed buds. Still most formulas have us feeding too much of everything right to the end. I start backing off after week 5 in a 9 week strain. I want to see fan leaves yellowing the last couple of weeks so I know my plants are using up any stored nutes and giving me cleaner buds. Just K, MG, sulphur and carbs the last couple of weeks to fatten the buds and crank out the resin.
It's weird. Organics indoors in pots is still hit and miss for me but my first grows outside teh last two years not a single problem with the plants. They grow like weeds and stay green right to the end. Planting my own F1 fem autos out there this year in a sunnier spot and making F2s with them. Mazarilla by Urban Legends.
Ignore the middle one. An unrelated CBD auto. Fans stripped off earlier in the day in prep for chopping the next day on Sept. 11. 6 honest ozs off each at 32" tall so should do better with another 4 - 5 hours of sun each day. Long days up north here but a short season so autos are the bomb for that.
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