Forsythia and Crabgrass

My forsythia is in flower. Is it too late to put down crabgrass control?

 No! It’s not as simple as watching for forsythia blooms… Many people use forsythia as an indicator for crabgrass treatments, but forsythia flowering should be the sign that it’s time to START planning pre-emergent crabgrass control applications. Generally crabgrass germination is not expected until after Forsythia flowers have faded and fallen off. Even then there are many variables such as air temperature, soil temperature, sun exposure and turf density.

 Research has shown that crabgrass germinates when average daily soil temperature reaches 57 to 64 degrees at 1 inch depth. Even then many crabgrass seeds will not germinate until the soil temperature is above 70 degrees. Turf density, mowing height and soil structure all affect soil temperature and therefore crabgrass germination.

We can also use Growing Degree Days (GDD) to predict crabgrass germination. GDD is based on the measurement of air temperature above a base temperature of 50 degrees Farenheit. Science tells us that crabgrass will germinate at about 200 GDD. (It’s the end of March and we’re still below 90 GDD.) However all those variables about soil temp, density, etc. still come into play affecting exactly when this pesky weed will sprout!

Normally the first place we find crabgrass sprouting early is in sunny, hot dry areas like the south side of a building in lawn surrounded by pavement which contributes to heating the soil. Crabgrass likely won't sprout until June in more protected areas.

The key to success with crabgrass control is to properly maintain the lawn with good fertility to increase turf density. Mow high to shade the soil. And apply pre-emergent control before crabgrass sprouts!

The good news is that Weed Man applies two full applications of crabgrass control that work as a pre-emergent AND a post-emergent. What that means is that we protect the lawn with a blanket to keep crabgrass from establishing, but if there is “break-through” our 2^nd application will stop the crabgrass plants from gaining a foot hold.

So trust us to take care of crabgrass and we’ll trust you to take care of proper mowing and watering. Be sure to check with us if you need advice on proper care of your lawn. 

Call us at 413-736-9333 or 860-903-1110!