Not too long ago I saw on the list suggestions for "sterilizing" the soil. Please send the procedure again. I have been preparing my landscaping areas, planting, Preening, mulching and using RoundUp on the perimeters. Some areas on my 4+ property, though are too large to mulch but I do want to grow grasses, daylillies, wildlife landscape trees and shrubs. Mowing these areas and the high ridge behind them is time consuming. It looks great when the grass is mowed and the weedeater used... this doesn't last long, though. I can't afford mulching this large area. Is sterilizing the soil an option for me? How long would it last? How close to ther existing plants can I get IF this is a "doable" option?