Question
We live in Washington, NH at an elevation of 1500'.We are on a steep wooded hillside with the lake out in front of us. For 12 years we have had a thick, green, weed free, beautiful lawn. This year the lawn has crab grass, other weeds,is yellow in spots (big circles)and the grasses seem to lie down rather than stand up straight.We have alot of moss and the lawn has been slower in growing and needs mowing only every other week. Previous years we have had to mow every 5-6 days. We have not changed the way we fertilize or applying lime.Any ideas?

Answer
Sounds like the lawn is not doing well. Yellow circles can be sign of insect (try to dig into root zone between green and yellow spots and scout for c-shaped maggits: grubs).

Can also be diseases such as rhizoctonia blight (brown patch) which are caused by a fungus which create large round dead spots. This fungus is most active in very hot weather (80-90F) where lawn is consistently moist. If it has rained consistently or if you have watered frequently (especially in early afternoon or evening hours) this may explain it. Try to water in early morning hours and only water once or maximum twice per week (but water deeply with each watering).

In your area, fertilize lightly in spring, more heavily in early fall and late fall and never - ever - in summer.

To battle crabgrass, dig as much as you can this summer and fall. The weed will die with first frost and you can then apply a fertilizer w/crabgrass preventer in early spring (late april) before weed seeds germinate (usually around time the yellow forsythia bushes starts to bud).