This cloudy weather is really annoying. I need sunshine! I saw some stats on February–only 4 days of sunshine! March isn’t much better, damnit.
OMG, the forsythia are blooming! The forsythia are blooming!
Don’t panic! You’ve got LOTS of time, folks! There is a lot of misinformation regarding the best time to apply your crabgrass prevention product. It’s understandable because all the LCO’s (lawn care operators) are making their first applications and posting signs. The hardware stores have huge piles of their crappy retail products.
I’ve been monitoring the soil temperatures on the southwest exposure of my lawn, in an area of decent turf. Last week when it hit 73 degrees, the soil temp at 2 inches was only 46 degrees. Today it’s back down to 39 degrees. Crabgrass is considered to be a warm season annual. It germinates at 55 degrees. The forsythia bloom has turned out to be a reasonably accurate phenological indicator for crabgrass emergence, but it’s the END of the bloom, not the beginning. So relax!
When you see farmers in the fields planting corn, that’s a better indicator!
So why are the LCO’s applying their product so early? It’s simple. First, it’s a money-maker. Second, most good companies have a lot of properties to cover, so they go out early and make a Round 1 treatment, but it’s soooo early that they really need to return around May 1st and make a second application, in order to provide you with season long crabgrass control. A lot of companies won’t make a second application though. Many wait and see if they avoid it, based upon rainfall and temperatures. Warm and rainy weather conditions enhance the breakdown of the product via microbial activity. Cool and dry conditions extend the life of the herbicide.
Try to avoid the Scotts product line because those contain way to much nitrogen for cool season turf in the transition zones, like STL. Try to avoid products using pendimethalin as the active ingredient. It’s an older generation product and doesn’t have the longevity on the soil surface like prodiamine (Barricade) and dithiopyr (Dimension).
If you have a great lawn you don’t have much crabgrass pressure. April 15th is usually a great time to apply a product with Dimension. For those of you with thin or weak turf, make two applications of crabgrass herbicide. You can use Barricade or Dimension early, up to April 1st, and then make a second application of Dimension by mid-May at the latest. The second application should be Dimension, because it will actually kill young crabgrass seedlings that may have escaped your first application. It will kill small seedlings up to 3/4 inches tall! Most LCO’s don’t even know this.
It is imperative that your product contain 12% or less nitrogen! Too much nitrogen in the spring causes excessive leaf growth, at the expense of the root system. That means a lot of crappy turf in August.
There are other posts on my website that discuss crabgrass control. Go get urself edecated…type “crabgrass control” in the search bar!
Best to you,