Last week I talked about applying grass seed for your lawn.. Well, maybe I spoke a bit premature, especially in light of yesterday’s post on community gardens and the map of the soil temperatures. These warmer temperatures in March have really brought to light a number of items that we might need to look at really closely with respect to our lawns and gardens. One area in particular is crabgrass and applying a pre-emergent fertilizer. The weather we are experiencing now in the midwest is similar to the normal weather in the southeast. As a result, I wanted to check out some articles on this topic. I came across this one article in particular and found the information to be very informative, “Lawn – Timing Pre-emergent Herbicide”
Walter Reeves uses an acronym I.T.Y.S (I told you so) His advice on applying a pre-emergent is typically March 15th and September 15th. The key is timing. You must apply the pre-emergent before the crab grass seeds germinate. Mr. Reeves also is not opposed to a second application in May.
His basis for these two dates is the soil temperature.
Crabgrass seed, you see, germinate when spring soil temperatures tend upwards from 50 degrees F. Weed scientists use 52 degrees F. at one-half inch deep as the trigger point for their application of pre-emergence herbicide.
This brings me back to those soil temperature maps. If you look closely, most areas are already above the 50 degree mark. I have started to see some grass and weeds coming in around my house. If you are like me, the timing seems incredibly early, but with a lack of moisture this winter and above average temperatures, it appears that our lawns may be in for a long battle to get established. Something to think about.
Picture via Clarity Jones