Let's dive into some different types of crabgrass while also going through its life cycle. Understanding more about its life cycle will help better your strategy when it comes to using herbicides to control this grassy weed. Here I talk about the different types of crabgrass and as I talk about its life cycle I sprinkle in tips on when to use pre or post-emergent herbicides to control these grassy weeds.
Crabgrass is the common name for a genus of plants (Digitaria) that includes annual and perennial types of grass. The species generally have broad, flat blades and produce long flower clusters and thousands of seeds per growing season.
This week I visited Grand Rapids, Michigan for a special purpose that will be revealed on my channel this weekend. Click To Subscribe
While there I of course went off into some neighborhoods to explore the lawns to see how they are fairing this summer.
The weather in West Michigan has been very very hot and dry during much of July but just about 12 days ago they got a good 2” of rain in a short period of time along with a nice cool down in temps which brought almost every lawn back!
But one other thing this “jolt” of “hot-then-rain-then-cool” did was rattle crabgrass seeds awake and now we are seeing weak spots in the pre-emergent game.
First off, download this FREE guide on how to stop weeds before they grow along with pre-emergents to understand how we actually PREVENT crabgrass.
Here’s the thing: even with the best pre-emergent strategy, you can have break-through, especially around high-foot-traffic areas and “hot zones” like you see in the pics here taken near the Thousand Oaks Golf Course.
This is a very well manicured and cared for subdivision. You can see how green the lawn is. It’s Kentucky Bluegrass and some fescue mixed in, cut tall and for sure it gets fert and weed control. Yet you can see those heat zones allow for breakthroughs.
Crabgrass lives fast and dies hard. It’s an annual and once it dies, it doesn't come back. The seeds that they drop, however, will come back the next year.
For example, in a typical cool season lawn, crabgrass seeds are in the lawn. Once soil temperatures near 55 degrees, that is the window for crabgrass seed to start germinating. Not all crabgrass seeds germinate at the same time. It really depends on where the seeds are in terms of depth, moisture, heat, etc.
When rains start for the season, a lot of pre-emergents will lose their vapor barrier and this is also when germination will start. This is where you can apply a post emergent weed control.
Once crabgrass is growing, it’s important to get on top of the problem fast. Each crabgrass plant can produce up to 150,000 crabgrass seed PER PLANT. That’s if you leave them to grow. Mow often to reduce seeds.
Once crabgrass dies, it will leave a bare spot in the lawn for the seeds to germinate the next season.
Here is a video to watch where I review the life cycle of crabgrass:
With any kind of lawn weed, including crabgrass, you will find that the problem takes a couple years sometimes to get under control. The goal is not always to “eliminate all crabgrass NOW” instead it’s a gradual reduction over 2-3 years.
You go after it with pre-emergents and post-emergents (quinclorac) and over time that will reduce the amount of seeds that get dropped which brings the problem to a halt in time.
I’ve got much more coming from my trip to Michigan, can’t wait to show you this weekend!
Al
