Young plants' leaves drying up

I have some young plants, a mixture of Arjan's Ultra Haze #1 and Mandala's Hashberry and Satori. Anyway, the plants are a few weeks old, and the area I've been keeping them is kind of cold, typically 50-60 degrees. They're not growing too fast, but until I'm capable of insulating and fixing up the grow area that'll have to do. I just checked humidity, and it read 70% at 52 degrees. It's raining outside now, and I believe it's usually lower than that.

Anyway, I've been having this problem with seedlings regularly, although my first two grows didn't have it. What happens is, the lower leaves dry up and get crispy while the new ones remain somewhat healthy. This really retards the growth of the plant. Eventually, most of my plants manage to grow out of it, but I think it still affects yield. The plants that seem to be immune to it tend to have the best yields.

pH is always normal, I checked it for my worst plant, and it was just under 7. The soil I used was just plain garden soil that I had put in an outdoor planter and successfully used to grow cannabis earlier this year with no problems. Light is an 80-watt T12 shop light with daylight spectrum bulbs.

Maybe half of my plants have this problem to varing degrees, the other half seem to be unaffected. Genetic differences don't seem to make a difference in whether the plants are affected. I have not been fertilizing my plants, but they are still very small and the soil they are in is rich, so I don't think that's the problem.

My current theory involves fungus gnats. They've been in my grow area on and off for the last year, and they could be spreading a disease. I put some hotshot traps in there to kill them, and I haven't seen any in a while.

Here are pictures of the three worst ones. Does this look familiar to anyone?

I used to get the same problem, it could be the quality of the water.
the top of your soil looks like toxic salts build up, where i live the tap water is very hard and once every othe week they flush the pipes with clorine (you can taste the shit), so i bought 2 x 30 litre water carryers off the net for about £20, and get water from my mother's house about 1 mile away from mine.. never had the problem again.
hope this helps mate.

I would have to say your issue is either water (chlorine can do weird things), or soil. How do you check your ph and what kind of water are you using? Maybe try adding some lime and a bit of perlite to the soil. I find soil from outside when put in pots tends to settle and be not so airy. Just thoughts but since you say it's reaccuring... makes me think it's one and/or the other.

90% of water in the usa doesn't contain chlorine. it has chloramine, which isn't harmful to plants, only fish. try covering your babies with a clear drinking glass after a light foliar misting to inhibit their rate of transpiration. if this doesn't help, i'd consider restarting them. shocks like these to young plants can slow growth throughout their entire life cycle. if you have no choice but to keep them in bad health, hopefully they'll get large enough to at least clone. best of luck.

spider mites? check under the leaves with a glass.

My tap water doesn't have a detectable amount of chlorine in it, although it is a bit high in minerals. Still, I've hardly been watering at all, so I don't think this is a major issue. I checked the pH by slowly watering until it started to drip out of the bottom, then checked it with litmus paper. And the pH is just fine.

One thing I did use is lawn insecticide flakes that contain pyrethrum. My last planting, half of my seeds were eaten by insect larvae (those damn bugs don't realize that's $10 a seed!), so anymore I mix some of the insecticide flakes with my starting soil. It's kept the grubs from eating my seeds so far.

I've had spider mites before and I know what they look like. These seedlings don't have spider mites though.

I tried turning on a fan in my grow room. It will probably cool the area because of the increase in circulation, but if there's a problem with the plants getting enough oxygen or CO2, I guess that'd be how you fix it.

The best way to avoid worms eating your seeds is to NEVER get dirt from out side.

If you are going to pay good money for seeds then you need to treat them right and buy dirt from the store.

Store bought dirt will NEVER contain any kind of bug larva. If you do have an out break get rid of the dirt after your plants have matured.

One bag goes a long way so it's worth it.

If you want to make cheap good dirt I buy a piece of foam from Menards and just break pieces off and rub them apart into little balls of white foam then mix them in the dirt. This gives the dirt breathing room and lets the plants breath a bit.

Also I have a spray that kills bugs and I just spray every time I see even one nat.

bug spray will not harm plants if you don't direct it right on the leaves but spray it in the air.

I am having the same problem with a bluecheese. It is small and the leaves are turning a copperish color and drying out/ falling off

513409 said:

I am having the same problem with a bluecheese. It is small and the leaves are turning a copperish color and drying out/ falling off

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Well, it's been a few years, but apparently this site still has my email address, so I get a notice when someone replies to my posts. I think the problem was that my soil was too heavy and possibly too rich. I should have just used really light potting soil to start them off. A mature plant can grow in richer soil than a seedling can. Also, my soil didn't drain very well, so it may have been too wet. I'm not sure what the problem actually was, but eventually they grew out of it.

i got the sameprob with 2 other young plants. one dryied up completely the other is starting to dry up

I would have said chlorine toxicity or calcium deficiency, but you stated that you used pyrethrum. The pyrethrum is most likely the cause IMO.