Q. My husband has a problem with moss growing in our back yard 100 by 100 feet. He has used moss killer, dug up the moss, and now reseeded it. He wants to know how to prevent future moss growth. Should he use lime to sweeten the soil? There is some shade in the yard, but mostly it is an open flat yard with good drainage, no standing water problems. Linda Shehan – Lakewood, WA
A. When moss out competes a lawn this means that the conditions are not favorable to the lawn. You say there is good drainage and sun, but is there good air circulation? This could be the most difficult to change since it could mean changing wood fences to chain link or some open form, or removal of dense shrubs. The soil could also have some compaction, which would favor the moss. If you have had a lot of foot traffic or vehicles have been on the lawn then core aeration would be needed. I would also recommend testing the soil for pH and major nutrients Nitrogen, Phosphorus and Potash and apply lime or sulfur (ph up or down respectively) and nutrients as needed. A pH in the range of 6-7 would be ideal for the lawn. There is also a natural moss and algae killer on decks, fences, roofs, and lawns made from 2% herbicidal soap that may be useful until you can improve the lawns growing conditions.