Wind burn, ambient temperature, deficiency, relative humidity ?

Moldy said:

I grow in 20% RH (all my life) and never saw that stress on my babies. The lights too close. Should be using T-5s until 3-4 weeks or raise that light about 2-3 feet. Don't feed those little fucker hardly anything yet.

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Yep, my RH is a constant 25% during the winter. I agree that's classic heat stress from the lights being too close.

I have air moving around but never directly at the seedlings. I flick them around with a finger tip when really small then slap them around like the bitches they are once they got a few nodes.

They toughen up or die and none ever die.

Appreciate the answers from everyone, I have backed up the lights in order to reduce stress, also added a humidifier.

Jimmy the vest uk said:

Makes sense to me thanks for input you just helped me so much! I reduced nutes soon as I realised they wasn’t happy I put it down to over nutrients as I just switched up to all mix instead of light mix, now I learnt that I got yellowing because I still need a little nutes as well, whenever I see unhappy plant first thing I do is cut nutes and feed water in case of nute burn probably an amateur move but I cut out one potential problem by doing it this way after a couple waters I add low dose nutes and normally see a recovery but not this time so I learnt it’s something else

seriously raise my lights will increase humidity

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Thats not what I meant. He needed to raise ligjts first off. Put a humidifier in there if need be to raise relative humidity up. Around 55 to 70 % rh. Hes got wiggle room with temps at a higher humidity up to a point. And after all that he needs to bump down the strength of his fertilizer feeds. Marijuana plants can take alot of subpar coditions. It will apdapt and chug along but if you really dial the environment and lighting in they will respond accordingly. Lots of noobs on this grow forum. Lots of noobs. And they give some fukt up advice to other noobs who dont try and play the pro role after a few crops.

since1991 said:

Thats not what I meant. He needed to raise ligjts first off. Put a humidifier in there if need be to raise relative humidity up. Around 55 to 70 % rh. Hes got wiggle room with temps at a higher humidity up to a point. And after all that he needs to bump down the strength of his fertilizer feeds. Marijuana plants can take alot of subpar coditions. It will apdapt and chug along but if you really dial the environment and lighting in they will respond accordingly. Lots of noobs on this grow forum. Lots of noobs. And they give some fukt up advice to other noobs who dont try and play the pro role after a few crops.

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Sometimes it's a bit of mis-communication too as I thought you were saying that raising the lights raised the RH too when I read the original post but didn't comment at the time.

If that wasn't you please disregard the above paragraph with my sincere apologies!

You are right tho about newer growers and even more experienced ones giving really bad info. They get all up in your face if you politely try to correct them too. LOL

Merry Xmas!

Cannabis is an easy enough plant to grow. Quite tolerant. But wow. These forums can get wild with utter crap advice. Blowing a fan directly on seedlings? Cmon. I can tell you know what your doing. But its these kids today..and I know they are third grow pro kids. In thier 20's maybe early 30's if that. And they maybe started growing 1 to 3 years tops and they banged thier frikin head with crop after crop. Until finally pulling off something half assed that looks like quality. Rinse repeat. And they get on these forums CONVINCED they know whats up and master green thumbs. I usually can spot em within 2 sentences of a post. This forum in particular is rife with em.

I frequent a few forums and am Admin at one and this one isn't really any worse than the rest. The tone seems to be improving too with the trollish types mostly staying in the forums where such churlish behaviour is not only tolerated but encouraged. Members where I have the say get two warnings and then a time out for infractions and if they continue when when they come back they see my banhammer up close and personal and they're gone. Lively discussion is fine but when it slips over to abuse it's not tolerated. Really slow there but a great bunch of guys. Chat box too we call the Short Bus. My bosses are the Prince and Princess of pot but haven't seen them in years.

There ought to be some sort of knowledge test with your score under your avatar so nOObs getting advice can judge how much worth the advice is likely to have. I'd be up for that. A timed test so it would be harder to just google the info and plug in the right answer. Multiple choice. 4 choices and 30sec per question. 20 questions for each section and a warning before the test that there is no bathroom breaks so be prepared to work for 10 min solid. A pool of 100 questions for each section so do-overs get a different mix. Just like the professors did when I went back to school for a diploma in environmental chemistry in my early-mid 30s. Tough 3 years but I made it.

Basic pot plant terminology for section one then different categories getting progressively more difficult as the tested progresses to higher levels. Be fun to get a bunch of advanced growers together and set something up. Bound to be some with some teaching cred with more than my fundamental grasp of how these things work in detail. Someone who could write some code to track things and generate a random 20 questions from the pool for each section. Likely free software out there that does that already. Would probably have to have a separate web site to do the testing as it's unlikely it could be made to work in the forums here but I don't know much about that either.

Man my mind wanders when I medicate after dinner.

Mine too. I feel ya. Good post. Makes sense.

Kieron90 said:

Hey guys

I have done a bit of digging in the sticky threads but can't find an answer I can be sure of, hence coming here.

Ambient temperature is about 21 degrees, and radiant temperature is 31.

Plants are on 1.0 EC canna nutrients feed on a wilma system every three hours.

I increased the feeds to three hours on account of the low (10% - 15%) humidity.

They're under an air cooled 400w metal halide at about 9" height from the pots.

View attachment 4057822

This leave curl is happening across my entire system (there are two tanks), under two different lights, I don't think it's a nute problems as they're dialled in as per tried and tested quants, strain is critical mass 2.0.

View attachment 4057824 View attachment 4057824 View attachment 4057823 View attachment 4057822

If anyone can give me some advice that'd be great !

Cheers

K

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Back your lights up like a good foot. Your young plants will still be getting enough light. Let them "grow into the light". To me it looks like youre frying the seedlings. Also prolly why the heat is high and humidity is low.