aguro
Member
My seedling is about a week old and I noticed the tips and edges of the first pair of leaves have started to turn black/brown. It hasn't been growing much the last couple days either. The seedling is in a peat cup filled with a cactus mix of soil (peat moss, sand, compost, vermiculite, & perlite) with extra perlite and I have been waiting a couple days in between watering. The PH of water drained through the soil is ~7.6.
The picture shows the lamp after I discovered this problem. It was about an inch and a half above the plant before. The lamp directly above the plant is a 150 W Cool White CFL, I also have a 75 W Soft White CFL off to the side and a 100 W Cool White over another seedling in the bigger pot. I have a oscilating fan going (in the 2nd picture) that does not blow directly on the seedlings, but above them into the corner creating a breeze (you can see the tall one shake a tiny bit when the fan blows toward it). The temp measured under the lights is ~80 F constantly, as the lights are on 24/7.
What do you think is wrong with my plant? I suspect its heat stress, so I moved it another inch or so away. The seedling stretched a lot when it sprouted so I may have overcompensated and put the light a bit too close.
Another possible issue may be PH. I just got a water meter and measured the filtered tap water I've been using and it was ~8.2. Could this also contribute to this discoloring? Could it be overwatering? I was misting everyday before a few days ago when I soaked it and have been letting it dry since. I've prepared water with a PH of ~6.7 (with lemon juice) for its next watering, and I'm waiting til tomorrow maybe for it to dry out some.