...to get my seedlings to look this amazing.
Here are a couple cheap ways to get the heat going in your seed trays.
Under the beer box is a hot water bottle and you can see the milk jug. I crushed it so it would be flat and cover a large space. Strangely enough the milk jug stays warm longer than the hot water bottle. And I know the jug works because as soon as I put a covered seed tray on it condensation instantly appeared.
Another thing I did, and I'm thinking it helped, was to sprinkle kelp powder on the plants as soon as they popped up. Seaweed is an excellent fertilizer. You can buy a small packet of it from the health food store for 1.99. And a little goes a long way.
Next step is to find a way to get my beans out of there without disturbing anything else. The box is just about ready to decompose, which is just what I was hoping for, but I still need it to hold out for a few more days. Just until I can get more pots and the weather to warm a bit.