Hello Everyone, My plants are experiencing a classic case of heat stress.. the edges of the leaves are turned upwards at nearly 90 degrees on a lot of the leaves, and the very tips are drooping downwards. I have my plants under a 400W Metal Halide light, which is about 2 feet above the plants. There is a fan blowing steady air in between the light and the canopy and the plants are getting movement from the air circulation. My fan was set to "low" and I have increased it to "high" today.. that might help. The temperature range is 79-83 degrees F, with a humidity which fluctuates between 50% and 60%. The average heat index for the room is +1 degree F, so the plants are experiencing a 83.9 degrees F temperature at absolute maximum. The room did get up to 68% RH for about 12 hours last week, but I've added a dehumidifier on a timer which keeps the RH down to the levels I stated. They are getting watered when they need it, every 2nd day or so, and they are getting full vegging nutes now (18-18-21). There was some slight yellowing in lower leaves which hasn't gone away, but hasn't gotten worse now that I've gone to full strength nutes. This seems like classic heat stress, but everything I have read and experienced myself says that these are ideal vegging conditions.. am I missing something? Does anyone have any tips? I'll post a photo tomorrow if requested. My cameras battery is dead and I dont want to waste your time with a cell phone shot. I don't know who posted it, but this is exactly what it looks like: http://i267.photobucket.com/albums/ii308/help_needed_photo/_MG_1100.jpg Any and All Advice is appreciated! Thanks Everyone! ~Experimentalist
hrm i really need a pic. but from what you described (and as you said) those should be perfect conditions. edit: 18-18-21 is not a good vegging nute ratio IMO. you want high N and less P and K. could have something to do with that. maybe they're getting too much potassium (K).
This is a photo of what I am seeing on all of my plants: http://i255.photobucket.com/albums/hh159/experimentalist/SANY1866.jpg Hmm.. good point about the potassium.. I will go get new nutes tonight. Thanks!! ~Experimentalist
Ok I've given the plants a full dose of some 30-10-10 nutes I got this evening, I hope they take to it OK. I am noticing some new yellowing happening in the leaves today which is kind of scaring me. If it's worse by tomorrow evening im going to do a full flush on them, then give them a half dose of nutes, then wait a few more days to see what cooks. ~Experimentalist