I strated using jiffy pots years ago, and transplanting, but as the number of plants increased into the hundreds, the cost of the jiffy pots, and the time spent transplanting, made it worthwhile to directly plant into 3.5" plastic pots filled with seed starter. The pots can be reused over and over, and there's no need to transplant except to the garden itself. As for space, I've set up shelves with flourescent bulbs. When the plants are too big for the shelves, it's time to start hardening them off (next week, maybe). Tom