The most ecologic method I know of is soil blocks, but it isn't cheap
either. The park starts are way too expensive, too. The most economical is
plug trays, like the professional bedding plant growers use. We have used
them for ten years now. See my article in National Gardening (Jan 1992?) on
starting setups for more analysis. If someone asks, Alison or Warren will
upload it to the forum.
Shep Ogden