I'm trying two different varieties of cabbage this year. My old standby variety "Copenhagen Early Market" seed were not available due to a crop failure for the grower. "Copenhagen" had it's problems, being an heirloom it was susceptible to Black Rot but it is an early maturing variety which I like. This year I'm growing "Farao" and "Capture". "Farao is a 63 day hybrid and "Capture" is an 85 day hybrid that is resistant to Black Rot. We'll see how these two varieties perform.
I did see that I had a few "Copenhagen" seeds left over from last year but I've learned cabbage is one of those crops that the seeds don't stay viable for more than a year so I'll just toss those seeds out.
I grow my seeds in the unfinished basement and since it is a bit cooler down there than in the house I put a heat mat under the rack holding the seeds trays. If you are starting your own seeds, a common technique is to put the seed tray on top of the refrigerator, it's toasty up there from the heat of the fridge motor. Keep the soil moist but not soggy and the seeds should sprout in 7-10 days. Watch for the sprouts, once the seeds have sprouted they won't need heat as much as light. Lots of light!! If the seedlings start getting tall, they are screaming for more light...it's sad to hear little plants begging for light. I use florescent lighting, 15 hours/day and only 1/2 inch over the tops of the plants.
Although it's take a little more effort to grow your own transplants the end result is worth it. You'll get specific varieties you want, when you want and you'll have the satisfaction of seeing a crop from seed to table.