I just thought I'd mention this, as I'm browsing around in the germination forum. For many years I used flats or the trays of little individual plant "pots." They would dry out if I forgot them and so I tended to overwater. A couple of years ago I happened to plant my seeds in plastic window boxes - about 10 inches deep. I found that the extra soil kept water that seemed to rise when the top dried out. I was less obsessive about watering, could leave them for a long weekend, etc. If I didn't get around to transplanting in a timely fashion, they just developed nice deep roots. I'll never go back to the shallow trays.
That is really interesting, as I have just bought 4 window trays on sale at Walmart- 24" long- $1 each! I got them for the same use- instead of planting my tomato & pepper seeds in individual small pots, I plan to sow them in the planters and prick them out when they are ready & transplant into styrofoam cups. I already have some stacked shelves set up in my sewing room- I'll add lights later before it is time to start. We expect our first freeze this weekend, so my garden will be about done. Hurry next spring!