Question
This may be a part woodworking and part gardening question so I thought I'd start here. I have built several wooden planter boxes for my deck. Since cedar was not in the budget, I used pine. I'd like to brush something on the inside to help protect it from moisture and the outside finish, but I need something that will not harm the plants. In the past I've purchased boxes that nothing would grow in until I lined the inside with plastic. That's not an option here.

Do you know what I can use that will fit the bill?

Thanks,

Steve Gerow

Answer
All wood preservatives that are brushed on contain solvents whose vapors can harm humans, the environment, and plants. Wooden containers, therefore, should be painted at least eight weeks before they are planted, to allow time for evaporation. Under no circumstances should these products be applied indoors. The alternative is to give the wood an overcoat of natural-resin-based-clear varnish and let everything dry thoroughly for eight days.
Several coats of sealer can be applied, to prolong the life of the wood.
The best solution, if you have the time to spend, is to use natural stains and colors that Mother nature produces.
You have to grind down various plant matter, add water or a slight amount of natural occurring oil, then paint the boxes. With this method you do not have to use the plastic liner. For a natural finish, you could use pitch from pine trees and a little oil as a lubricant to treat the planters. Natural colors could also be added.
bakerplanter