Lights should be kept immediately above the leaves. Almost touching. You want as much light as possible hitting the leaves and, with LEDs, there is zero chance of heat damage. I have a set of boxes and boards near my lights that allow me to prop them up to the right height. Seedlings need 6 hours of dark. Most seeds don't need light to germinate. I believe lettuce and carrots are exceptions to that.

I use fluorescents because, in my converted garage, it can get chilly. In order to keep everyone warm, I just throw a sheet or blanket over the whole setup. That might not work that well with LEDs.

The cats kill me, that's awesome. I actually had to move my grow light operation to the garage because one of my cats enjoys digging in the dirt...sooooo keep an eye on that, especially when something is actually growing.

Lights can be up to 4" above the seedlings but since these are not actually grow lights, I would monitor the seedlings and switch to grow lights if indicated. We bought T5 bulbs from HTG and they were pretty inexpensive. I've read that High Efficiency LED grow lights do not need to be adjusted, which is a huge bonus for me.

Adding a heated seedling mat can really speed germination very quickly, especially if the space is cold.

Cool Cats! Your set up looks similar to my 48" florescent shop light configuration (of which I want to phase out). Mind if I ask where you found yours? Lowe's, HD, on line? Thx.

@daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa): Thank you so much. Will do. This is a spare bathroom and its is quite warm in there actually. I am able to adjust the height of the lights via the chains they are hung, how high tech! So lowering the lights vey close to the seedlings wont be a problem.

@Anna (6B/7A in MD) Thank you!

@vgkg Z-7 Va: I got the lights and the shelving on Amazon starting from the recommendation of an YTer and then browsing a little. I dont know if I got the best price or the best lights in this price range. I just wanted to get started. Maybe I will get something different in a few years. By that time I will know better what I want and there may be better options.

https://www.amazon.com/Barrina-Reflector-Integrated-Fixture-Daylight/dp/B08B44WG93/ref=pd_bxgy_1/136-7449807-0152329?pd_rd_w=EDEzf&pf_rd_p=6b3eefea-7b16-43e9-bc45-2e332cbf99da&pf_rd_r=S7994H2NDXDKNDW6F4NA&pd_rd_r=66ca6735-26f3-4c94-90f1-1ba81b9c5197&pd_rd_wg=aqUHx&pd_rd_i=B08B44WG93&psc=1

https://www.amazon.com/gp/product/B07FXH81ZT/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B07TRNF4CV/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

Hope you find what makes you happy.

I have both LED and Fluorescents. If I lower the LED to almost touching the seedlings do not like it at all - its too intense. A few inches is better. I like the LED which are in light tube form (like fluorescent) . I have some of the 'spotlight' types and they need to be much further from the plants - especially the red/blue LED types. I have never done 24hrs, use 16-18 max. My setup is inside at 65F

Anna said it well. Monitor the plants closely because the shop LED's you have are not grow lights. If the plants become leggy with long skinny stems and short narrow leaves you may not have the right color light plants use.

Sunlight is made from many colors of light and you can see the different colors with a light prism or looking at a rainbow, and each color has it's own spectrum or wavelength. The color of the rainbow which plants don't use is green and is reflected away, and why plants are green.

The problem with shop LED's is they have a narrow wavelength (limited color) so you need the colors plants use.. An LED grow light will usually be called "full Spectrum" with all the colors or only have the blue and red wavelengths, but a shop led has a narrow spectrum emitting a narrow range of color. But this doesn't mean your shop lights won't work.

Light colors can also be expressed as Kelvin color temperature and would be listed on your LED shop light packages. If the Kelvin color is 3000K to 4000K (and called soft, natural or warm white) they emit mostly green light with some red and will be a challenge for your plants no matter how close they are to the plants. If your packages state the kelvin color is 5000K to 6500K (called daylight) They have more blue light and the color or spectrum plants use.

You don't need full spectrum grow lights to grow health seedlings, you only need lights which emits the most energy in the light color spectrum your plants need, red or blue. If your LED's are 3000K lights most of the energy is in the green color plants don't use. I'd suggest if these are what you have to exchange them for lights in the 5000K spectrum where more energy is emitted in the blue light spectrum plants use.

Anna is spot on again. "Adding a heated seedling mat can really speed germination very quickly, especially if the space is cold".

I noticed from your other posts you will be growing peppers. Peppers need a lot of warmth to germinate and grow. Peppers are always my hardest because I grow in the basement with cool temperatures. I use heat mats and have the rack (like yours) curtained with clear vinyl shower curtains from target ($5) taped together to keep the plants warm and all sides including the top and bottom are covered. I've had varieties of peppers take a month to germinate so warmth is important.

I use regular old T8 4 foot florescent fixtures but with 5000K bulbs or 6000K if I can find them, I don't need grow lights. I keep the bulbs a couple inches from the plants. The curtain is closed in the front and I use magnets to keep it shut. The orange rope is used to move the light fixtures up and down running through pulleys from above.

I wouldn't worry too much about grow-lights. I've used them, and switched back to regular fluorescents, and never really noticed much of a difference. If in the ground, it would be nice if the sky were completely clear every day, and the plants got 8-hours of full sunlight, but that usually doesn't happen. They'll grow anyway. Regular "daylight" bulbs have enough light at the right wavelengths to do the job adequately.

That's true that peppers like warmth to germinate and grow. They're slow! I now have a dozen peppers under lights, at about 70F, and in doing so, it always is striking how long they take to germinate and grow. About two weeks just to germinate! That is, they germinate just fine at room temp, but probably would do so faster if warmer. Also, they won't be ready to plant out for three weeks. Everything else I start indoors goes out two weeks after they come up.

Thank you, thank you so, so much for your thoughtful input everyone. I do get the impression that my set up will be satisfactory. The room is warm and the bulbs are 6500K, so daylight type. And yes, the heating mats really help.

The above all sounds like good advice. Adding my two cents would be not everything needs 16 to 18 hours of light in particular cool season stuff. My experience is that when those get transplanted outside after 16 to 18 hour a day under lights there is a high tendency for them to bolt quickly.