How often do I adjust the grow light height?

My seeds have sprouted in 3 days (whoohoo ) using a heating mat which I was just amazed with. Now I have removed the plastic film and hung a 24" florescent grow light 2" above them. How high should the light be above the plants? How often should I adjust its height? Do I leave the light on 24/7 or turn it off at night?

Igolfat8,

You'll want to maintain that 2" distance above the seedlings. So check them often and adjust accordingly.

Turn the lights off at night, they need their rest too!!! Maximum hours of lighting should be no more than 12 hours per day.

---Dave

As mentioned above, adjust height of light accordingly. I usually run my grow lights about 14 hours. I hope you have removed the sprouted seedlings from the heat mat.

Oops, I have not removed them from the heat mat yet. Why should I do that? Would the warmer soil temp aid growth or is it just needed for germination?

Once they sprout, they prefer a cooler temp.

I keep my light on 16 hrs a day and try to keep the light 2-3" above the tops of the plants at all times.

Igolfat8,

Yes, the seedlings should be removed from the heat mat provided all the germination is done. Given that sometimes you don't get 100% germination OR germination is a bit sporadic (as it might take a day or two extra for ALL the seeds to finally germinate), you'll need to watch them closely. But as soon as you're pretty sure all the germination that is going to occur is complete, then take them off the heat mat and continue with the lights only.

A couple of rules to follow:
1) When using light keep them close to the canopy of the plants and limit the amount of lighting to 12-16 hours. If the lights are not kept up close, the plants will want to "stretch". Because they are reaching for the light.

2) Remove the bottom heat as soon as all germination is complete. The heat was applied to get them to germinate. After that, continued application of heat will only promote "spindly" growth. Like as in skinny stems instead of stronger/thicker stems. So remove the extra heat that was only needed to get them to sprout. It's one of those "less is more" kind of things.

Hope that helps explain more about WHY you want to apply these techniques (treatment of light and heat) in this way for sprouting your seeds.

You said your seed sprouted in three days!!! Here's to you, that's awesome What were you sprouting?

---Dave

We sprouted two kinds of tomatoes, Egg plant, red and yellow sweet peppers and marigolds. I used a kit from Burpee that uses their peat pellets and water wicking mat. I thought it came with a clear plastic canopy but it only came with Surran type plastic sheets to cover the planters but I guess it did its job of keeping the moisture in. I planted the seeds late Wednesday night and Saturday AM most all were sprouted.

watch them close once you put them under the lights....they grow fast!

i have adjusted some of my seedlings in the am to have them touching the light by pm.....

also a timer for the grow light is a great help too....my hubby picked one up for 8 dollars and it is so worth it....i kept forgetting to turn on or off the lights

hugs

rose