This shows a newly planted flat on the left and a flat that was planted 2 weeks ago (March 15). The first flat used ‘discount’ pellets and I missed a deep hole in the center of each pellet that many of the seeds fell too deeply into the holes and most never sprouted. Sometimes shit just happens, adapt and overcome.
My tomato seedling nursery is in a bathroom we do not use. A sheet of plywood over the sink is my grow table and lamps suspended from a shower rod provide lighting. I use 300 watt CFL bulbs at 6000-6500k on the temperature scale. These give off the equivalent light intensity of a 300w bulb, but actually consume less power. 400-520nm in LED lighting. These lean more into the blue spectrum for vegetative (leaf and root) growth. You will find them as ‘daylight’ bulbs (as opposed to warm white or cool white).
I also use a heat mat for sprouting since tomatoes love heat. The heat mat for seedlings is designed to work differently than the heating pad you use for sore muscles which will cook your seeds. The light is on a 16 hour timer each day, with 8 hours of dark.