I think I'm killing these little guys
I'm new to growing with HPS and my past experience is limited to a couple of semi-successful 1 plant grows in an old stereo speaker. My new set up is a closet grow 6'x2.5'x3' with a 400w HPS. I'm yet to install the extractor fan which I'll be doing this weekend so the plants are getting fresh air by leaving the door on the closet open with a 6" oscilating fan blowing across the plants. The light is currently about 12 inches from the tops of the plants.
I've got 7 plants, all about 1 month old grown from seed. 5 are 'Purple No.1' and the other 2 are Blue Mystic. They are all showing signs of serious yellowing on the lowest leaves, some of which are dying and crumbling up. The plants haven't looked good for a week or so, with most of the leaves either drooping or curling inwards (as if they are trying to avoid the light - see pics). But they've never looked as good as most of the grow journal ones I've seen on here
Temps in the grow room are 78f in the shade, 90f with the probe under the lights (not sure which is the reading I should use?) and humidity varies from 45%-55%.
I started adding veg nutes 8 days ago, at first going with the 100% solution the bottle recomended - Bio Bizz Bio Grow NPK 8-2-6. Its also been getting a product called Hygrozyme. Even after reading the label I'm not sure what it is or what it does, but the guy at the shop swore by it so I got some and have been adding a little less than the recomended dose to the water. After reading on here that plants need to be eased into nutes I watered the remaining bucket of nute water down to 50% solution. That was 5 days ago and since then the plants have only been getting half the recomended dose of nutes with every watering.
I got the suspicion my plants might be root-bound so I transplanted 3 up to bigger pots yesterday (from the original 5" pots to 10" pots) and changed the soil to a much lighter mix (and better quality) with about 25% perlite. The original soil had become very compact, almost like dried mud
I've got a horrible suspicion I've been over watering.
I'm going to transplant the others tomorrow as the 3 I have already done seemed to have perked up a little in 24hrs. I'm not convinced this is the main problem though...
4 possible cause (that I cant think of anyway)
1. Overwatering - I think I've made for the classic noob error of watering too much. The plants have been getting at least a full saucer (about 150-200ml) of water every day because the top soil always looked dry and the plant seemed to be sucking it all up. I didn't read about the 'lifting it up and feeling the weight' method until a couple of days ago.
2. Temps/Humidity - I've struggled to keep the temps down (have got up to 93f with the probe under the lights) as security has been an issue. The door has been left with only a small gap at times and its got pretty warm at times. Some of the lower leaves (see pics) have dried up and flake off which makes me think the heat might be a problem. This will hopefully be solved when I get the extractor fan installed and vents cu in the doors this weekend.
3. Nute burn - I did go with the recomended bottle dosage and the plants were about 3 weeks old when nutes started so I thought things would be okay. And it says its okay to use EVERY watering. Yet I've now read on threads on here that you should ease them in with a 25% solution and only every other watering? If thats true maybe I've nutre burned em
4. Light proximity - I've varied the height at times as I thought they might be getting too much light. But I read in a book that even HPS lights can be placed within a few inches of the plants and that for every inch further away it decreases its effectiveness. So for most of the month the light has only been about 12" from the tops of the plants (always with the fan blowing over them though)
Pics:
BM01.jpg - One of the Blue Mystic plants with the yellow/brown/dying leaf. The otehr lower leaves are yellow and all leaves are droopy
BM02.jpg - Another shot of same leaf
BM03.jpg - Shot of other Blue Mystic in closet with same problem
BM04.jpg - Close up shot of bad Blue Mystic leaf
The rest of the shots are mostly of the Purple no.1's with the curled in leaves. As you can see they are looking quite weedy now the leaves are closed in.
I'll let the pictures do the talking now as I've rambled on long enough ... thanks for being patient if you read it all
any thoughts are greatfully appreciated