Growing conditions vary across Washington from the Eastern to the Western portion of the state. However, both climates are well-suited to fine-leaved or turf-type tall fescue. These and other cool season grasses thrive in the mild summers and cold winters of Washington. Most cool-season grasses are quite hardy, so Washington lawns only require a minimum of care. However, Washington is susceptible to a few pests and weeds that lawn owners should look out for.
Water your lawn deeply, so that the water reaches below the roots of the grass. But only water the soil when the top 2 inches of the soil are dry (test by sticking your finger into the soil). Over-watering may result in the growth of butter cups, annual blue grass and speedwell. Check for dry soil more frequently in the summer when Washington experiences less rainfall.
Fertilize your lawn four times a year with an N-P-K fertilizer with a 3-1-2 ratio (for example, 21-7-14 or 15-5-10). The first application should fall between mid-November and early December, the second in mid-April, the third in mid-June and the last on the first of September. In general, Washington lawns need 4 pounds of nitrogen per 1000 square feet per year (spread out over the four applications) but follow the manufacturer's instructions for application rates.
Mow your lawn regularly. In general, Washington lawns comprised of fescue grass grow best when they are kept at 1.5 inches in height. However, mowing height depends largely on the variety of grass that you are growing.
Control weeds. A healthy lawn will crowd out a significant infestation and any stray weeds that pop up can be hand-weeded. If a large weed infestation occurs, have a professional diagnose the problem.
Aerate the soil with a core aerator in September after a light watering. This is especially important if your lawn suffers from high traffic and is hard and compacted.
Control moss. Washington lawns that grow in too much shade, too thinly or suffer from poor drainage are susceptible to developing moss. Fixing the underlying problem is the best remedy. This may be re-seeding with shade-resistant cultivars, over-seeding tin grass or improving drainage in the lawn. In the meantime, kill the moss with a moss killer that contains ferrous sulfate.
Cranefly is a common pest for Washington lawns. Their larvae chew through grass roots and crowns which results in dead spots. If you suspect that you have a problem, dig up a square foot of your lawn and flip it over. Count the larvae; if there are more than 35 larvae in the square foot, treat the area with nematodes. Cranefly insecticides are quite toxic and are dangerous for your pets and kids to come into contact with.