Calcium? Phosphorus? Bugs? This is only happening on 1 plant in the tent, the others don't show any signs of this.
I'm guessing off the bat it's possibly Phosphorus deficiency. I don't see signs of pests. You should've taken a pic of the whole plant before snipping off the affected leaves. That would've helped us in knowing what parts of the plant the deficiency was coming from. If you do have one, posting it would help. If not, what part of the plant were the majority of those leaves coming from? What medium are you using? What are the room temps and R.H. and how high above that plant do you have the lights?
Coco coir 70f ambient temp, 80f canopy temp, rh 50% 600w hps in a vented hood 20" above canopy I have had a few fungus gnats, but nothing crazy. I put out 5 yellow traps and maybe caught 20 flies. I also let the Coco dry out a bit between waterings for the last week, but this mottled rust started before any of this
If we're specifically speaking ONLY about the rust spots all over those leaves (because you said the rusting started before the pests issues), then after looking at the new pics and comparing deficiencies, it came down to either Phosphorus deficiency or heat stress. Phosphorus deficiency (from my understanding) usually starts from the older, bottom-most leaves. This deficiency is focused on the top-most leaves. Plus, I need to know if the cupping of the leaves was there along with the rusting or did it come after the pests issue? If the cupping came with the rusting, then I'm going to lean toward heat stress.
Thanks for your input, I really appreciate it! So the rust spots started as just yellow dots and stains and became more severe as the weeks have progressed. The cupping leaves are only on the severely burned/browned leaves and only started cupping in their final stages before crisping up. When you say "speaking only about the rust..." can you see any other issues I should be concentrating on?
You're welcome. Did you notice any change in the affected leaves after you took care of the fungus gnat issue? Did they even reach the top-most, affected leaves? If not, then I'm forced to keep leaning toward heat stress. Severe cases of heat stress tend to look a lot like the top part of the last pic you provided. Perhaps, it's possible, it could be (lol) that just that top-most portion of the plant is too close to the lights. Just my two cents. Take my advice with a grain of salt. I ain't always right, but I'm brutally honest with what I do know. If I'm wrong, I'll be the first to admit it lol.
Unfortunately even after clearing up the gnats, the problem has gotten worse. It's also weird that is has only affected 1 of 4 plants growing in the tent, if it was heat stress wouldn't it affect a few of them?
Depends; are the affected leaves coming from the plant with the tallest colas? Are there colas taller than these under the same light/height?
Yea, there are a few taller buds on other plants that should be burning up first. I also have a temp and humidity sensor at canopy level. Doesn't ever go past 85f
So the plot thickens lol. I never did ask you; what's the pH of your waterings/feedings? Has it ever been off this whole time? You ever had any root issues with any past grows? Are they all the same strain? Some strains handle heat better than others. "I also let the Coco dry out a bit between waterings for the last week" Can I ask why you do this? I'm actually curious. From my limited understanding of growing in coco, it should always be moist, but not wet or dry, since it's considered hydro. Also, if you're using R.O. water, you have been adding Calcium to her feeding schedule since the get-go, right?
pH has been consistently between 5.8 and 6.0, I always calibrate and actually have 2 pens to cross check (I'm a bit anal with these things) These are all Northern Lights Auto. I was letting it dry on the surface to help prevent any remaining fungus gnats laying eggs. Always added between 0.5ml per L to 1ml per L of CalMag every feeding
Dude, I'm stumped then lol. You really got me scratching my bald head here. I'm going to sleep on this one. Perhaps someone else will chime in and point something out that we're both missing. I'm not sure what to suggest, except maybe to raise the lights a couple of inches and see if that helps?
I'm getting the same problems in dwc I wish I could help Sent from my SM-G960F using Grasscity Forum mobile app