I used a biodome for peppers and tomatoes this year (and herbs, leeks and celery root) and discovered that starting leeks in a dome is a silly idea. Leeks shoot up like a green onion and quickly outgrow the dome.
Although most of the tomatoes germinated pretty well in the dome, they too outgrew it and had to be transplanted. So now I have peppers and celery root (and a couple tomato plants that were puny) still in the dome, where they will remain until it's time to plant them outside.
I replanted all of the tomatoes in individual pots and stuck them under the grow light. I think they're pretty happy. Now the trick will be keeping them happy and growing inside for another month until it's safe to plant them outside.
I want happy plants that will be well-adjusted so they can get serious about producing early tomatoes! Is that too much to ask?
Yes, I know... I could probably buy happy well-adjust plants from a local nursery, but what would I have to do in early spring without my obsession?