My trays are 21" x 11"
Shelf is 48" x 18"
I guess I could put four trays per shelf. They would just have to hang over 1-1/2" at the front and back. Didn't think of that. I was going with two per shelf (on just two shelves). May have to get more heat mats now....hmmm...
My shelf unit has four shelves, but I wouldn't use the top one because lights would have to be put into the ceiling and I can't do that. They are wire shelves so I won't have to drill holes for the lights.
I thought I'd have to use two light fixtures per shelf because I read that the lights should be a few inches from the plants. I didn't think the light would reach to the outer edges if they were so close to the plants???? The fixtures are 48" long but just 2-3/4" wide.
Bulbs are T8, 32Watt, Daylight, 2850 Lumens.
Right now, I'll have 4 lights, 4 heat mats, 1 timer, 1 fan. Ya, that's 10 plugs already.
This will be set up in a heated porch. North windows so no direct sunlight.
An added issue I may have is figuring how to keep our cat away from the plants
