Q. It’s April and my lawn is full of crabgrass, what can I do?
A. Crabgrass is an annual plant and does not even germinate in NH and VT until mid or late May. Any grasses you see now and suspect are crabgrass, are not. They are perennial grasses and may appear to look like crabgrass. This is a very common misperception. Unwanted perennial grasses need special care including manual or herbicide removal.
Q. I always have crabgrass, nothing seems to work, what can I do?
A. Crabgrass generally indicates an underlying problem like unhealthy soil, recent insect damage, or some other event that allow it to flourish rather than your lawn. Although pre-emergent products work great, in the absence of surrounding grass, the barrier will fail and the problem will reoccur year after year. Only by improving the soil and adding superior grass seed into the infected area will you ever conquer this ongoing issue.
Q. I typically dig out crabgrass and weeds, is this doing more harm than good?
A. Whenever you tear up any plant, you bring up more of the weeds’ seeds to the surface where they will germinate. While you may have temporary relief and feel good about removing crabgrass manually, you are actually making the problem worse by depositing seeds that would otherwise have remained dormant buried below.
Q. When is the best time to apply crabgrass control?
A. In NH and VT, there are several types of pre-emergent control products that do a nice job by safely preventing not only crabgrass, but also many annual weeds from germinating in the soil. A pre-emergent is the best product and means to reduce crabgrass. By definition, a pre-emergent must be applied before the crabgrass rears its ugly head! Soil temperature is the big deal here and once mid to late May arrives, you are likely to have crabgrass germinating; especially in sunny locations like along your driveway, walkways, or roadside. Once crabgrass germinates and while still small, in the two or three leaf stage, there are other products that can be used to still gain control. For larger crabgrass, you would need to switch to yet another specialized material for use through August. Once fall rolls around, just let this annual plant die off. However, the best way to prevent crabgrass is with a thick healthy lawn created with healthy soil, adequate nutrition, and by mowing at the proper height (2” first cut of the season, 3” May – September).
See my blog http://www.mrgrassblog.net/2012/03/30/crabgrass-is-more-than-a-crabgrass-problem/ for information on crabgrass.