We don't appear to have a Hydroponic thread, so I'm putting this here hoping "Gardening in the Green" is the right place.
I have just found some info which I should share as it's very clever, and will save time.
Visit here and watch the video at the bottom of the page.
http://www.bigelowbrook.com/Products...p/Default.aspx
Neat eh? A much better way of starting seeds to give you clean roots.