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Are my lights too strong? Dead seedlings..
Posted: Wed Apr 27, 2011 6:48 pm
I've been having trouble with keeping my seedlings wet enough to avoid cooking over night with my lights. I bought 75 watt plant lights, and am using potting soil in my starter containers. (Why is potting soil so difficult to get wet? (The water collects at the top and then drains through the bottom, and the soil is never wet afterward for some reason.)
Anyhow, I have the cone shaped reflectors and 4 bulbs above my trays and if I leave them on for the normal 16-18 hours a day, they always cook my little seedlings and I end up starting over. The lights are around 3-4 inches above my plants right now. Any advice?
Posted: Wed Apr 27, 2011 7:27 pm
Re the wetting - potting soil with peat moss is difficult to wet at first. Dry peat moss repels water. I put mine in a container BEFORE I plant anything in it and pour a lot of water (helps if it is warm water) in it and stir it around well. Once it is wet and absorbing water nicely then I put it into planting container and plant in to it. Once it has been thoroughly wetted you won't have that problem again unless you let it get all the way dried out again.
I'm not sure what you mean by "plant lights." Are they incandescent lights (the old style, pre- compact fluorescent light bulbs, with filaments, that give off heat)? If you have incandescent lights just a few inches above your plants, then you are definitely cooking them. Easy to tell, put your hand under the light. You do not want it to feel warm. Fluorescent tube lights give off minimal heat.
Posted: Wed Apr 27, 2011 8:45 pm
They are giving off heat - do I just need to raise them a little higher to prevent cooking? I was going to get the shop lights with florescent bulbs, but was advised by the garden person at Lowe's to go with these ones..
Posted: Wed Apr 27, 2011 11:09 pm
Those look like spot lights for lighting plants (make the plants look good). I don't think that they are for growing plants...Anyways, nobody uses them for growing plants (probably because they cook the plants). If you want to go with the round reflectors for a confined space you can buy specialty CFL curly tubes up to 115 watts or more on line. I have three 105 watt CFLs over my growing table. They are about a foot long and put out almost no heat (similar to any other fluorescent), but they cost like $25 each.
If you go with the biggest curly bulbs that Home Depot carries to replace the bulbs you have they will be something like 100 watt "equivalent" which are only 23 real watts (a single tube for a shoplight is 32 watts) so you might think about adding another reflector or two and reflective surfaces around the plants if you decide to go that route rather than buying a couple of shoplights.
Posted: Thu Apr 28, 2011 12:10 am
Darn! Are these pretty useless then?
Posted: Thu Apr 28, 2011 12:11 am
Aya wrote:They are giving off heat - do I just need to raise them a little higher to prevent cooking? I was going to get the shop lights with florescent bulbs, but was advised by the garden person at Lowe's to go with these ones..
You need to put those bulbs in a closet or drawer and get real lights. To be basic - you are wasting electricity, providing the worst spectrum for the plants and will be disappointed with how the plants grow. Like TZ said, get good grow lights, ones made to encourage, duh, plant growth. I have several 105 watt CFL bulbs and if they touch the plants, they will cause some burn - but that is only if they touch
them, not get close. They will put out a lot more lumens, lumens that have far more PAR light - the light plants use to grow.
Posted: Thu Apr 28, 2011 1:00 am
Darn. Guess I'll be asking you guys instead of the gardening folks at Lowe's which lights I need to get..
Posted: Thu Apr 28, 2011 6:37 am
Unfortunately true. The people in the garden dept at Lowes are the same people that work the cash registers, etc. That is, they don't particularly have any garden knowledge. I know because a good friend of mine used to be one. Their job there is to sell you stuff!