Hi all, am in need of some help identifing this problem. This is Big Bud/White Widow cross. I grow in hydroton, recirc system. Its my 3rd grow with no problems before this. I keep PH at around 5.7, checked twice a day. I keep nutes at around 1.4EC to 1.6EC. Its been bloody hot lately and because of where the set is Im at the mercy of the ambient temperature so inside the tent its been getting in low 30'sC lights off and mid to high 30'sC lights on. I was running 2X1000w but have just swapped to 2X600w on digital ballast that has variable wattage. My hydroponics supplier says its wind burn from the fans blowing hot air on plants, which it may be. I have put fans on ground so air blows around ratger than on plants. The lower leaves are/were worst affected but even the newer leaves are developing the same discolouring although to a much lesser extent. The top leaves tips are turned up while the lower ones are turned down. The leaf serrations are a yellow/brown colour. The odd spots are brown not white. Any advce is truely welcomed. Cheers
A massive heat swing, then these symptoms showing up is kind of a red flag that makes me think you are a ways outside the VPD safe zone and losing too much water too quickly. This can actually lead to slowed nutrient uptake, crisp and malformed or twisted leaves on the newer growth or leaves that are still gaining size. Are your leaves starting to get leathery? They should feel supple, smooth, and cool, not like sandpaper. Especially the newer leaves. If they are getting a rough feel, they are not happy, and probably sweating (transpiring) too much. What's the humidity like in the room?
Thanks trojangrower. Have just satrted adding RhinoK which is a potassium booster. I do flush pretty regularly. Hopi ng it comes good
During the real hot period when it was 35 to 40+ degrees the RH was quite low, 35-38%. Now its 45-50%. The newer leavs feel ok the older ones are a bit rough. The odd one or two blades of a leaf are twisted and deformed but only a very few.
mid to high 30'sC lights on Its too hot. You need to reduce to 30C unless you have CO2 and proper lumens.
Well you were definitely quite a ways outside the zone. The plants would have needed a RH range of about 65%-75% to prevent from losing too much water to the environment. Plants can take it here or there, but a plant acclimated to a specific environment for most of its life then subjected to a massive swing can sometimes be hit pretty hard. A plant grown in 30% RH most of the time will do well. A plant that has had ample humidity then suddenly hit with dry air can be affected negatively. That, or doing what I did and just subjecting the poor things to too much light keeping the light too close, and heating the leaves too much for ages. I did that for so long, even though my plants are happy now, the leaves will probably never uncurl. What you are seeing is how my plants showed their signs early on. Burnt tips, crisp serrated edges, twisting here or there, started getting leathery. Not saying that is what you were seeing but your symptoms are similar to mine. Good luck, hopefully no more heat waves for you.
and Johnny Stash is right to mention moisture. You're ggrowing in the Sahara! ok maybe that's exaggerating, but still. During veg its good to keep 60-70 even higher during flowering its better to keep 40-50, for trichome/oil production. Cannabis shouldn't be 'picture perfect' imo. It should be stressed a bit with some extremes. Abiotic stress induces trichome production. nice plants Johnny Stash
Thanks man! Not sure what's with the popcorn explosions coming off them randomly but hey, it's weight. Kinda doing the Medusa thing lol
Mine are White Widow. Yeah I got a couple teas too hot, and then with the insane light intensity lol....poor things. Early on I had them at 140W / sq ft ! Lmao!! Much better now under the panels and being able to keep my temps and humidity stable.
Thanks for the replies. Im moving to a new place soon that I hope will be able to give me more control over the growing environment. At the moment it's 37C outside and 32C in the tent lights off. Nothing I can do about it. I purchased a good sized portable AC a few weeks ago, put it in the tent and it shate itself in about 2 hours. Thanks again, really appreciate it.
I really hope you took that AC back and got your money back! I bought a cheap Comfee dehumidifier from Walmart and that thing has been running well for a long time. Easily 50 gallons out of my room air since I got it.
Yeah got my money back. If I lived in the States instead of Oz I'd have a house with a basement and wouldn't have this problem. I lived in Texas for about 6 months once. Was amazed at what was for sale at places like Walmart and Lowes and other stores.
I had the 1000W + 3 HLG100's + 2 50W LED UFOs in a 3x3 or so area lmao!! The ambient temps were mostly normal, RH was good. But my fans and dehumidifier were running constantly, and the leaf tops were cooking. So much happier now. The weirdest thing is how used to the noise I became of 4 different fans, a ballast, and a dehumidifier running. Now the silence is deafening lol.
May be because no tornadoes and something to do with the water table although in Coober Pedy there are whole houses underground