roots ; mowing with a sharp blade to the right height -LRB- ask your local garden center what 's best where you live -RRB- ; and fertilizing in spring and fall . So promise yourself -- and your turf -- you 'll do that this year . In the meantime , here 's how to conquer the most common turf problems you 're likely to confront this summer . Fungal disease Symptoms : Circular patches of yellow-to-brown grass ; or blades with tiny red threads . Culprits : Powdery mildew , brown patch , dollar spot , and fusarium patch ; or red thread . These fungal diseases can take hold of stressed turf . Solutions : Though lawns will generally recover from small areas of infection , if a fungus is progressively marching across your yard , look for a fungicide with the active ingredient thiophanate-methyl and follow the directions . For an organic fix , search out a corn-gluten mix that will cure brown patch and weaken most other fungi . Then nurse your lawn back to health by practicing good lawn-care habits : Avoid excessive shade -LRB- prune back trees and large shrubs , if necessary -RRB-
-LRB- This Old House -RRB- -- Unless you 're a perfect caretaker of your lawn -LRB- and , really , who is ? -RRB- , prepare for another round in the turf wars this summer . You 'll have to deal with a full frontal assault from the dandelions , of course . And an attack from the crabgrass . But you 'll face more stealthy opponents , too : root-chomping grubs and microscopic mildew that turn the grass from green to gray or brown . `` If a lawn is neglected , or cared for in a hit-or-miss way , it gets weak , '' says This Old House landscape contractor Roger Cook . `` And that 's when weeds , insects , or fungal diseases become a major problem . '' Little wonder that last year almost 50 million homeowners bought products to fight these invaders . But as in most battles , the best defense is a strong offense : doing everything right to cultivate healthy turf . That means giving it up to an inch and a half of water per week ; aerating and dethatching annually so water and nutrients can get down to the