Nutsedge has been found to be 1 of the 20 worst weeds in the world and fortunately for us Northern Californians we are one of the locations that Nutsedge calls home. Nutsedge is undesirable mainly due to its appearance and evasive growing habits. Nutsedge is a fast growing perennial. That typically starts showing growth in the late spring time around May/June.
Nutsedge is hard to eradicate due to its root function. Nutsedge has underground tubers. A typical person would notice that pulling this weed only leads to a new one forming in as little as a couple days. Nutsedge does grow faster than your typical grass, creating a scenario where after a couple of days the nutsedge already has outgrown the height of your freshly cut grass. Nutsedge enjoys very moist environments. You can find Nutsedge in planter beds and grass areas that have very bad drainage issues. Installing proper drainage and aerating are two ways that can assist with your drainage problem with the latter being a temporary solution and the first option being the best solution for continuous results.
With Nutsedge growing in the late spring, aerating and applying Pre-Emergent in early spring will help get a control on this weed and slow down the growth if it was present in your lawn the previous year. There is truly no way to fully eradicate Nutsedge unless you plan on digging up your lawn and tilling your soil in order to breakdown all of the undergrown Tubers (root system of the Nutsedge).
Completing Aeration and a good Herbicide treatment in the spring time will be your best defense in protecting your lawn from Nutsedge. If your lawn is currently free of Nutsedge ensuring that it has good drainage will also be good insurance in assuring that no Nutsedge finds a home in your lawn.