I've got some lettuce started to grow in a season-extending greenhouse.
How deep does the soil need to be to get good root growth and hence good
sized heads? I'm planning on using some old window boxes, with drainage
holes drilled in them.

The good news; I dug into the old part of the back-to-back compost bins,
and there's nothing there but about a foot deep layer of beautiful black
humus.


Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic
Zone 5/6 in upstate New York, 1420' elevation. NY WO G