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#1
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Flourescent lights/leggy seedlings?
I'm curious if I'm doing my lighting right for my seedlings. I have
one of the Professional Jiffy Greenhouse 72 peat pellet seed starting kits, and I'm starting my seeds for my garden. Anyway, I have two 18" flourescent fixtures- one with a GE Plant & Aquarium tube, and one with a GE Chroma 50 tube. I set the fixtures/tubes directly on the plastic greenhouse top, and rotate them each day, so that the plants get an even mix of Chroma 50 and Plant & Aquarium light. The vast majority of the seeds sprouted quick, and are growing madly- most of them have their cotyledon leaves & stems almost to the top of the plastic greenhouse top- they look kind of spindly right now. No true leaves have shown up yet. Is this a problem, or is it common for the cotyledon leaves to shoot up really high and quick? I read that lack of light will cause leggy plants, but I'm not short of light with my setup, am I? |
#2
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You are a bit ahead of schedule, aren't you?
Totally depends on where he lives. He's not ahead of schedule here in Zone 9. I already have six flats of seedings well under way. most of them have their cotyledon leaves & stems almost to the top of the plastic greenhouse top I'm not familiar with the Jiffy Greenhouse, but if it has a removable greenhouse top, it should be removed when the first seedlings sprout. How long are you leaving the lights on? The plants need around 16 hours of light from fluorescent fixtures. Make sure you keep the tubes as close as you can to the seedlings without them touching. Cereus' suggestion for a fan is a good one. Also, to strenghthen the seedlings' stems, gently run your hands over the tops of them every day, lightly brushing them a bit. -Fleemo |
#3
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In article .com, "Mark" writes: | | Is this a problem, or is it common for the cotyledon leaves to shoot up | really high and quick? I read that lack of light will cause leggy | plants, but I'm not short of light with my setup, am I? The usual cause is too much heat relative to the light, which is a nightmare in the UK - we can get leggy seedlings OUTSIDE in extreme circumstances! Try keeping them cooler, at least from when they start to emerge from the compost. Regards, Nick Maclaren. |
#4
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#5
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Mark wrote: The vast majority of the seeds sprouted quick, and are growing madly- most of them have their cotyledon leaves & stems almost to the top of the plastic greenhouse top- they look kind of spindly right now. No true leaves have shown up yet. Is this a problem, or is it common for the cotyledon leaves to shoot up really high and quick? I read that lack of light will cause leggy plants, but I'm not short of light with my setup, am I? you are definitely short of light. the other pieces of advice are pretty good, and they will improve your light efficiency and prevent damping off, but they won't solve your main problem, which is too little light. You can evaluate things yourself. In full sun, with the sun overhead you get about 600W/m2 of light. With the sun at 45 degrees, you get 420W/m2. Each 72-cell tray is about 0.18m2, so you should be coming in with close to 80W/tray. Those fluorescents are fairly efficient, but they are not 100% efficient, so make that 100W/tray. I found that the only thing that helps is a sunny window, and taking them out to full sun as soon as feasible. |
#6
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Zone 8a. Mid-March is usually the latest frost we'll see around here
You're right on target then. Most seeds should be planted 6 to 8 weeks before the last frost. Ah. Didn't do that, although I'm only about 2-3 days off from when everything sprouted Definitely take off the lid. It'll help with air flow, and if there's a lot of condensation on the lid, it may be cutting down some of your precious light. I'll try that - will a ceiling fan running in the room work? I'd try a small oscillating fan closer to the seedlings. I have mine set up in a closet, so a small fan is sufficient to keep air circulating around the plants. If it doesn't oscillate, I wouldn't point the fan directly at the seedlings as it might dry out the potting medium faster. Another thing I do is to surround the planting trays with a small "wall" of aluminum foil, which bounces more light back on to the seedlings. This definitely helps with the seedlings I place on a sunny window ledge, as I don't even have to turn the trays around -- the seedlings no longer lean toward the sun when the light is reflected on them. -Fleemo |
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