This happened literally overnight, plant was heathy yesterday afternoon. It happens on the the second compound leaf only, and appears it may happen to a few others as well (some leaf dimpling happening). I included a pic for staging as well to show the healthier other leaves. Temps range from 20C-22C during nighttime, and 25-27C in daytime. Humidity was up to 70% when I entered the room today (highest it has been since seedling stage). Growing in peat, General Hydroponics nutrition, Mild Veg moving to Aggressive Veg Friday. pH I know is on high side (7.0), but if I water with a wand then I can’t lower it with pH Down. Our water is higher EC (343 prior to adding nutrition), but I have grown successfully before. This is all ‘to spec’ as best as I can research aside from the pH and the higher humidity. I lowered the humidity to 60 for the night… will this be pH related for certain? Am I to water by hand moving forward?
It looks to me like a ph fluctuation issue here’s a copy paste from growweedeasy if you want to check out the whole article search growweedeasy once there search for ph fluctuations it was the first one on the list when I searched
pH Fluctuations
by Nebula Haze
Quick Summary: Managing pH is crucial for cannabis plants to be able to take up nutrients through their roots. When the pH around the roots jumps up and down, it can stress the plant and cause brown spots to appear on the leaves. Spotting on the leaves as a results of pH fluctuations is more common in hydroponic setups (where the pH tends to go up and down), but it is possible it can also happen in soil. This seems to often happen when the pH swings too high or low.
Note: You can also get these symptoms from root issues
This is definitely ph fluctuations for your issue because I had the same thing the other day when I got ahead of myself and watered right after making the water and not ph balancing it to 5.9-6.0. I fixed this issue by watering till runoff with the correct ph water and then 2-3 days later the plant looks fine again
I use GH (lucas formula) in sunshine #4(peat based). And treat it like hydro.
All of my reading says that PH should be 6.0, I like to vary between 5.8 to 6.0.
I had the same symptoms on my latest grow in early veg, she grew out of it with proper PH.
Peat is a soil less mix, much like coco or any hydro and anything from 5.2-6 will work but generally we advise people to aim for 5.8 +/- 0.1 ph
Your medium has been given ph 7 so your plant is slipping into lockout of nutrients and showing ph flux as pointed out by the above members.
Ph your water to 5.8 (no nutrients) and run a 5 gallon bucket through it in the tub or sink.
Then mix up a 5 gallon bucket of a full feed mix and ph it 5.8 and feed that while draining into the sink or tub to allow runoff and thus giving a full flush.
Feed 5.8ph nutrients to 20% run off from start to finish on soil less grows.
Also a piece of advice if your growing in soil less medium you should get a silica product.
Clever, thank you for the advice everyone. I think they are too small to flush… but I never thought of pH adjusting the flushing water… brilliant. I will do so when they are big enough. The pics I sent were still in 1-gallons.
