I want to put some creeping thyme and Sagina s.(Scotch Moss) along the edge between the deck and the patio I put in last summer, where there is a wide area of white sand about 4-6" thick. My concern is that the sand is too deep for the plants roots to get down to the soil quickly. I'm thinking of either mixing in some time-released fertilizer with the sand when I plant or skimming out the sand, partially back filling with some compost/soil then planting and adding the sand to the top. Any suggestions/experiences as to which solution would work best? The area is south facing and gets full sun until mid afternoon. Terry King E. WA. zone 4