The past few weeks I have been adding a few mixes to the garden boxes. A healthy amount of Paet, Vermiculite, and Organic potting soil. I think I went to high on the peat. I have turned it over several times to really mix it together. Read some interesting articles about the bad results of roto tilling breaking down the soil too much. I didn't go that far! I am generally following the Square Foot Gardening method. Have my grid all laid out. Not sure who built the raised boxes, but 29 inches? really??