I am not an expert in these things but I tell you what I am doing. The heating Mat is removed or turned-off as soon as I see any sprout. I have home made green house (not a fancy one) In the Basement I several tables and old desks with flourcent lamps hanging from the ceiling. I have over 100 4 Inches plastic pots with good drainage put on plastic plates. I leave, may be one foot between the lamp and the Plants. As soon as the pot sprout I move it from the heating Mat. I read if you leave it on the heating mat it will grow long leggy and thin. As for growing lights I leave 24/7. From my observation Tomato, Cuccuumber, Squash are growing like crazy, Pepper Egg plant are growing but very slow.

Thanks for the advice, I'm leaving the snow. I was out there this morning, everything just looked so cold with all the snow on top. Hope the plants are ok in there. We are supposed to have single digits off and on all next week, with no day above mid 20's. The heating cable is an interesting idea, but this coldframe is about 120 feet away from the house, so the extension cord needed would be considerable. It's built into the south side of a rock retaining wall. It's about 12 feet long and 2-3 feet out from the wall, so it's pretty good size as coldframes go, I suppose. I have some baby leeks, red romaine, chinese cabbage and broccoli in there in the ground. It's the broccoli I'm most concerned about, as it is about 10 inches high. Guess I'll just wait and see what nature deals me....

Hmmm.... Well, there seems to be several different beliefs as to how to do this. Yes, you could remove the lid a few hours every day until you finally just leave it off. Another way would have been to place the whole pot inside a plastic baggie, soak the pot pretty good, seal the bag and leave it for a year! Believe it or not, I know of a few people that use this method religiously and just about always end up with fat, healthy seedlings twice as large as any of my year old seedlings! But I've always done as you have except I've never fertilized as they're usually too young to handle the fertilizer. SO, I'd cut the fertilizer and just keep removing the lid for a little longer each day... although, being seedlings, they are adapted to a higher humidity. They grow under the shade of a "nurse plant", be it a larger cactus, a tree, a bush or a weed. Where ever it grows, it usually has more moisture than you'd expect. Guess that's why the 1 year bag method works as well as it does. But don't be afraid about watering them. If they start to look too round and fat, then maybe skip a watering or two. I will say, Of all the seedlings I've grown, the ones that always seem to do the best and get the largest are the ones I didn't plant and just discover growing under a larger plant! This could just be because I don't know how long it's been there, or because it's growing under the conditions it evolved to grow under. Hope your seedlings do well how ever you do it

I never remove flowers, but I also don't ever plant tomatoes with flowers already on them (I plant them when they are 8-10 weeks from seed and they never seem to have buds by this point). A lot of my plants had little flowers on them when they are 12-18" tall in the ground (planted deep) and I left them, a few fell off with some cold nights we had. A few of the flowers have set and I have some 2" green tomatoes now. The plants didn't stop growing because the fruit had set - they are all good sized now some in the 3-4ft range which is pretty good for southeastern PA. My opinion is that the plants know better than we do when they are ready to set and mature fruit - so I leave it alone as far as that goes and have had good results... AND early tomatoes :) As far as pruning goes, 3-5 main stems is fine if tying off is your method of support. What I had tried when I had done pruning was develop some main stems and then prune suckers to a point and where the plants reached a decent height, then I just let them go nuts and drape back down towards the ground. Production was good and they were mostly manageable, although not very pretty, heh. Sure some fell over and some branches may have snapped in storms, but by that point it was nearing the end of the growing season and the extra production, as compared to continued pruning, was worth it. A little off subject, but have you ever heard of doing the florida weave technique? Relatively cheap and less maintenance than traditional staking. Personally, I've gone to cages and never looked back. It was an investment up front but since I plan on growing every year I can, they'll pay for themselves in time saved and production before long.