I wound up making a mix that was about 4 parts partially composted pine bark mulch (I screened some mulch from Lowes and tried to pick out any sapwood), 1 part MG potting mix, and 2 parts pearlite. It seems to drain well, and I'm going about 3 days between watering. Some of the seedlings on 2-10: Today, Rutgers in front, Early Girl in back: Polish Dwarf: Mini Bell Pepper (top left), Red Beauty (top right), Yummy Mini Bell (front 4): Are these plants on track, or are they lagging? These germinated between 01-22 and 01-30. I have them under 4 ft fluorescent shop lights with warm and cool bulbs. I keep them very close to the bulbs (1 inch). I left some pepper seedlings in their starters until yesterday, and they haven't grown much at all. I haven't been able to find good pine bark yet. I picked up some 'Dr Earth Potting Soil' the other day. Main ingredients are pine bark fines, forest humus, peat moss, pearlite and a bunch of organic fertilizers. I potted up some pepper seedlings in 3 parts Dr Earth and 2 parts pearlite to try it out. Thanks for everyone's advice.

I pot up many seedlings, but usually do this in the Spring. Sometimes I pot up the winter-sown seedlings to let them put on some size before planting in the garden. This seems to increase their chance of survival. I just planted out some nice 6 inch Foxgloves yesterday and the day before, that I had potted as tiny seedlings and let grow on for 4-6 weeks. I think you can pot up some Rudbeckia seedlings now if you want. If they are growing in a crowded littIe bunch they are probably competing for resources and won't grow optimally anyway. I would keep them some place easy to tend, where they only get a half day of sun (so they don't fry), and keep them well watered. Use a diluted liquid fertlizer about once a week. Or you could thin them out in the patch, pamper a little, and transplant in fall.

I agree I would never plant anything in peat pots and I definitely wouldn't plant pot and all.. When peat gets dry it is hard to rewet in the ground. It will simply run the water off of it. On year when I was a newbie to gardening I planted my tomatoes in them. They didn't do well and when we pulled the plants we discovered why. All the roots were contained in those pots. They never grew through the pots because the pot was never wet enough to make it penetrable. repotting depends on the size of your cell packs and the size of the roots on your plants and how big the plant is. I plant in flats and transfer most of my plants into 6 celled cell packs when they are big enough. Tomatoes and peppers go into 16 or 18 oz solo cups. However I don't plant extra early so I don't have huge plants. I use the weeks written on the seed package as my guide for when to plant my seeds and that works for me

Turfa (Portuguese), I suppose peat, yes. Thank you. I have updated my OP now (peat).