LED lighting on seedlings

Asked January 2, 2019, 9:57 PM EST

I have a full spectrum, 1000 watt LED grow light that I am using once my flower seedlings emerge this spring. I know 1000 watts is overkill but it’s what I have to work with LOL. I was wondering how high above the seedlings the light should be. I am curious because I will have about 300-400 plants and the light will have to be a distance above them in order to give light to all of them. I’m thinking since it’s 1000 watts it can be rather high above the plants. Is this a correct assumption? Any help would be appreciated, thank you.

Washtenaw County Michigan

4 Responses

Hi there! I'm not a horticultural lighting expert, but I know several people who are. Could you provide some specifics about the light? Make and model will help a lot. Also, are the LEDs colored or is it white light?

Sure Jeremy... its an iplant LED grow light 1000w, (15w LED), full spectrum color lights for veg mode, bloom mode, and veg + bloom, 15,000 lumens. Model TOP1000A.

Hello again!

I just had a short discussion about your question with one of our horticultural lighting experts. Here are a few thoughts:
  • Lighting companies should be able to provide light intensities (in photons) at a particular height from the fixture.
  • If they don't (or can't) then the next step would be to borrow or buy (preferably borrow) a reputable quantum sensor and measure the light intensity at plant level.
  • With a single fixture, there will be a lot of variation in light intensity across your seedlings. The likely result is that the plants will not grow uniformly (some will stretch more towards the light, etc). Its not necessarily a bad thing if you don't need a uniform crop. Moving the trays around on a regular basis may help mitigate some of the variability.
I hope that helps! Feel free to give me a call if you'd like to discuss this further.

Thank you so much Jeremy for your replies.