Tuesday, April 5, 2011
It’s now October but many lawns experienced a huge influx of crabgrass and nutsedge in August and September. Why so much, I applied weed controls? Let’s explore why this happened.
When lawns experience severe heat and drought stress they tend to shut down and go dormant. This is similar to a bear hibernating in winter: he’s still alive but in a slow, stupor of sleep. The good news is that dormant lawns will recover mostly.
Kentucky bluegrass is one of the first species of grass that turns “brown”, but it has an uncanny ability to recover and come back when normal temperatures and rainfall returns in the fall. Many of you have probably experienced this with the rainfall in the last few weeks; a lot of grass areas came back and are now growing well and greening up. Tall fescue also holds up very well under heat and drought stress. They possess a long, deep taproot that can access water from below when the surface gets very dry. Remember these two grasses when you plant new grass seed this fall.
Crabgrass control was poor this year even when customers used a pre-emergent this spring. The reason was a greater amount of rainfall than usual in June. When the crabgrass finally started to geminate the control products had already broken down. Hot, dry weather also is a favorite of crabgrass. When the desirable lawn grasses shut down as we described above; the crabgrass has little competition and it thrives. Unfortunately, if you did not try to control this crabgrass it produced a lot of seeds and will reappear next year. We would recommend using Jonathan Green’s Crabgrass Preventer plus Green-Up Lawn Fertilizer.
It is hard to predict each year if it will be a particularly bad year for crabgrass. One of the ways to get the best control is to use a soil thermometer and not apply your Jonathan Green Crabgrass Preventer plus Green-Up Lawn Fertilizer until the soil temperature reaches around 50 degrees. If you apply this control product a few weeks before this optimum time, the level of control drops off as time goes on. If it is a cool, wet spring, this delays the time that the crabgrass seeds germinate, which can make a big difference in the amount of crabgrass that appears. I am sure this is what happened to a lot of lawns this year. There also is a product available called Jonathan Green Crabgrass Preventer plus Green-Up Lawn Fertilizer that contains Dimension that provides crabgrass control both before and after crabgrass germinates, up to the three leaf stage. In this area that means you can still get reasonable crabgrass control with a late spring application.
Nutsedge was also a major problem. Nutsedge is light green in color; it has a wide blade and grows very quickly. One to two days after you have mowed your lawn nut sedge can be growing two to three inches faster than the rest of your lawn. Nutsedge has a triangular stem. Pull out a nutsedge plant and see the ‘nutlet’ that is attached to the roots. These characteristics make nutsedge easy to identify.
Nutsedge does not appear every year in the same areas of your lawn. It is naturally occurring in many areas and there are no preventative weed controls to stop it from coming. It is not introduced from grass seed. The drought and occasional downpours favor the nut sedge this year.
There are some nutsedge and crabgrass sprays and granular controls available on the market ask your local garden or hardware dealers for their guidance. Both nutsedge and crabgrass are harder to control when they get bigger and stronger, so try to treat them early when they first show up. Control crabgrass if possible before it sets out new seeds to prevent a larger infestation next year. Keep your mower blades at a higher cutting level in order to promote better lawn growth. Follow proper watering guidelines during periods of hot, dry weather. Apply about one inch of water weekly to lawn areas that are suffering from stress.
The good news is that crabgrass will die with the first frost in your area, usually in October. It will turn slightly purple and then die. October is still a good time of year to renovate your lawn from the summer’s damage. Use Jonathan Green Fall Magic Mixture to improve upon your existing lawn. Good seeding!Back