Everything I have read stresses the importance of keeping the light 1-2 inches above the young plants for adequate light. This is my 1st time using this method. So I have the t-8 with 6500k bulbs. I used the 72 cell with seed potting soil and a heat mat with the thermostat. I planted 4 different varieties. Amelia, celebrity, sun gold and black cherry . I planted jan 10 and by the 15th the majority had sprouted.
So what I am finding is that some are straight up others are very bent. They are now 1 week old.
I have placed the bulbs as close as I can to the tallest plant. I just added a 2nd shoplight last night so now I have 4 bulbs on 1 1020 tray. Is this typical in the first couple of weeks?
I realize it would be best if they were all equal distance 1-2 inches from the bulb. Is there anything that you advise?
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hendi_alex
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They don't literally need to be 1-2 inches in order to get good results, but probably no more than 4-6 inches. The first few days there will be some bending, probably not as much if you lift the lights a bit. I just rotate my round community pots, really don't notice a problem after the plants are moved to individual pots.
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rainbowgardener
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It is possible to over do the right down close to the plants. You have four fluorescent tubes for one 1020 tray, running cross-wise? That is what I do, except my tubes are four feet long, so they run cross-wise across four 1020 trays.
One inch would be too close. You would have to be raising the lights every day and have a lot of risk that your plants will grow up in to the lights and get burned. Two to four inches is fine. And yes your seedlings are teeny babies.
However, there are other reasons seedlings can bend over, having nothing to do with light. They can wilt from lack of water or they can "damp off" (a fungal disease) when they are staying too moist.
If your seedlings are very bent over and especially if they are flat on the soil, check the base of the stem where it emerges from the soil. If it is thinned, pinched in, and maybe a little darkened, it is damped off:
https://hort.uwex.edu/sites/default/file ... %20Off.png
If they look like that, it is very bad news. In that case all you can do is get rid of them and start over. Damping off can be prevented, but not cured.
One inch would be too close. You would have to be raising the lights every day and have a lot of risk that your plants will grow up in to the lights and get burned. Two to four inches is fine. And yes your seedlings are teeny babies.
However, there are other reasons seedlings can bend over, having nothing to do with light. They can wilt from lack of water or they can "damp off" (a fungal disease) when they are staying too moist.
If your seedlings are very bent over and especially if they are flat on the soil, check the base of the stem where it emerges from the soil. If it is thinned, pinched in, and maybe a little darkened, it is damped off:
https://hort.uwex.edu/sites/default/file ... %20Off.png
If they look like that, it is very bad news. In that case all you can do is get rid of them and start over. Damping off can be prevented, but not cured.
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applestar
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- Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)
I was thinking damping off too.
Also what's is the actual ambient temperature. In the beginning, best to put a thermometer at the top surface if soil mix and at the level of the top of leaves. Get a max/min thermometer or take note of those readings.
Also 1-2 inches is the guideline for T-12 lights which are cool enough that tender young leaves won't get burned even if they are touching the tubes for hours. I always say 2-3 inches for T-8 and 23-26W CFL's and 3-4 inches for T-5 as being closest you want to get. The narrower, more intense tubes also burn hotter.
Also what's is the actual ambient temperature. In the beginning, best to put a thermometer at the top surface if soil mix and at the level of the top of leaves. Get a max/min thermometer or take note of those readings.
Also 1-2 inches is the guideline for T-12 lights which are cool enough that tender young leaves won't get burned even if they are touching the tubes for hours. I always say 2-3 inches for T-8 and 23-26W CFL's and 3-4 inches for T-5 as being closest you want to get. The narrower, more intense tubes also burn hotter.