I have two lawns, one shady and one sunny. The shady one is overtaken by moss. We live in Seattle with constant rain. We have a drainage system there but it's still very wet. Now I have more moss than grass and bold spots started to appear. Surprisingly, our sunny lawn is bold too. We've been aerating, overseeding, fertilizing, mowing, watering. What should we do?
|Moss is usually a symptom of several problems, including poor drainage, too much shade, low fertility, compacted soil, and acid soil. If you can correct these problems, and put your lawn on a regular feeding schedule, you'll have fewer moss problems. I'd begin with a soil test. It may be that the pH is out of whack and you need to apply lime. If the soil test indicates a low pH, plan on applying lime this fall to help mellow the soil. As for care this spring and summer, start fertilizing in April with a 3-1-2 ratio of NPK (the 3 numbers on the bag of fertilizer). Apply one pound of actual nitrogen per 1,000 square feet of lawn per year. Feed again in June, September and late November or early December. Instead of using chemical moss killers, just rake and reseed any mossy areas in your lawn. If your grass is healthy, it will crowd out the moss in the future.
You did mention that you aerated your lawn. Aerating will help with compaction. I'd aerate again this spring with a core aerator, leaving the plugs on the lawn. Spread a thin layer of sand over the lawn and allow the plugs to dissolve in rain water or irrigation water. The sand and the soil from the plugs will work its way into the holes left by the aerator effectively reducing compaction and giving excess moisture a way to escape. This should help. Best wishes with your lawn!