Posted by John Franklin (207.238.176.243) on October 18, 2002 at 14:12:34:
My wife and I have a small organic farm in Michigan that we are operating as a CSA (Community Support Agriculture). I’m about it assemble a greenhouse for some cold tolerant crops as well as a place to start transplants. This spring we had about 1,200 plants in our basement and it could double next year. The problem is with the typical tube framed, poly covered greenhouse there is some would in the construction. Often pressure treated lumber is used around the perimeter in contact with the ground. This is not acceptable for organic gardening but I’m told that if I keep the pressure treated lumber off the ground it will meet requirements. Even this is not acceptable for me. There will be some water run off and therefore the possibility of the persevere leaching out and getting into our soil.
I must use a lumber type material but need a longer life than standard woods will give. I have checked into cedar but find it very expensive and hard to get in the sizes I need. Seeing that CCA’s are being phased out soon for residential use are there any reasonable, cost effective, safe substitutes available at this time. If so where would I find them? I realize that new things sometimes cost more but cedar is about three times the money and will not last as long as the current pressure treated products.
Any help would be appreciated.
John Franklin