Answer: The soil under your lawn can become compacted from foot traffic and mowing, and compacted soil excludes air (which roots need) and inhibits water penetration deep through the root zone. If grass is unhealthy and soil feels hard, aerating every 2 to 3 years is a good idea. Aerate when the grass is actively growing. If you rent a power aerator, it will dislodge plugs of soil. Leave the plugs on the lawn (they'll decompose and break down in the rain). After aerating, spread a thin layer of sand or organic mulch over the top of the lawn and then water deeply. There are also aerating "shoes" that have spikes. When you walk around the lawn they punch holes in the lawn. This is okay for a small patch of grass but not practical for a big lawn. You can also hire a landscape firm just to aerate the lawn.
Nutgrass (nutsedge is its proper name) is indeed a pesky foe! You have several options for controlling it. Although none of them are quick and easy, they will work if you are diligent. Assuming it is in the lawn, you can hand dig the nutlets. Then wait a few days for more to sprout and remove them immediately. A second option is to spray the nutsedge with a herbicide containing glyphosate (such as Roundup). However, if the nutsedge is in your lawn, glyphosate will kill the grass also. You can paint the herbicide on the individual nutsedge blades. Each time it returns, you have to reapply. Nutsedge is tenacious, and whatever method you choose, keep after it regularly. If you let it get a hold again, you've lost ground! The key to any approach is to never allow it to reestablish and regain its stored reserves, which are in small "nutlike" tubers below ground. Keep forcing it to use stored reserves to send up more growth and then quickly dig, rototill (if no surrounding plants) or spray it again. If you don't quit you will win!
Q&A Library Searching Tips