when to put seedlings under 400 watter

[hows.your.roof]

just wondering how many sets of leaves, days old. just looking for pertenient info?

[mikeyjo]

I usually wait until seedling stage is over - about 3 weeks.

[GaGrown]

You can put them under it now,if you have the head room? Just raise the hood up high.Make sure you have good ventilation.I've got 55 seedlings under a 600 watter,with no troubles.That 465 cfm fan helps get the heat out.My room has a thermostat to turn the fan on and off at 78 degrees.

Ga Grown!

[Mr. Clandestine]

I agree with GaGrown: if you can keep temperatures down, then you can add seedlings not too long after germination. The biggest problem with putting seedlings under an HID (namely HPS) is that the stems have a tendency to stretch towards the light, that is unless the light is very close to the seedlings. If you have an air-cooled hood, this is much easier to accomplish, and works like a charm...but if you don't, you'll risk possibly frying the seedlings by keeping them too close to the light. Do what works best for your plants. If they start showing signs of heat stress/stretching/etc., soon after being placed under the HID, then you'll probably want to think about keeping them going under less intense CFL's, or whatever you're using to grow your seedlings for a little bit longer.

[klondike_bar]

the last 2 posts nailed it. you can use a few cfl spiral bulbs to build it up a bit more, or see what happens with the lighting a good dist. overhead.

heats the worry, if you keep em cool, theyll love the light i bet

[hows.your.roof]

thanks guys

[GaGrown]

the last 2 posts nailed it. you can use a few cfl spiral bulbs to build it up a bit more, or see what happens with the lighting a good dist. overhead.

heats the worry, if you keep em cool, theyll love the light i bet

klondike,
They do love that Hps light!

Ga Grown!

[twoguysupnorth]

yes, keep your light high when they are coming from cfls. give them a couple of days at least (or 3 or 4)to get used to it. then lower it, as long as it doesnt get too hot and you water you will be ok. make sure you have a couple of leaves to loose if it is too hot.