There are two reasons for this. First is that we had an early warm spring this year that put plant growth two to three weeks ahead of normal when comparing growing degree days with those of other years. If your lawn has a severe crabgrass problem this year, your preventative control measures may have been put down too late to control germination. Mistiming of an application was easily done this year. Secondly, we’ve had warm and humid conditions for weeks on end, ideal conditions that allowed the plant to grow exponentially this year. Also, severe diseases removed vast amounts of Annual Bluegrass (Poa annua) from the turf creating voids that were rapidly filled by this adventitious plant whose seeds can lay dormant in the soil for decades.
Notice the lack of traffic tolerance of the crabgrass plant under the constant pounding of the beverage cart multiple trips over the same tracks.
Now the question I ponder is do I aerify Tri City fairways this fall through the extensive patches of Crabgrass with the knowledge that there are billions of seeds on stalks ready to fall into these newly made growth chambers? I’m coupling this with the knowledge that this is an annual plant and that any seed that would happen to germinate this fall should be killed by the first frost. In the first photo you can clearly see the crabgrass follows the contour lines of a fairway cut that is much closer to the ground. Was this caused by repeated fall aerifcations? (Answer “yes” to aerification this fall as this weed seed germinates in the spring. Better to have open holes now over next spring if the turf is weak. Also this is a good time to interseed your turf with desirable seed grasses allowing them the time to become established before winter hopefully with enough growth that they can grow and shade out any crabgrass poised to germinate next spring.)
Hopefully future budgets will allow the purchase of herbicides necessary to prevent spring germination or post emergence of this weed.
Speaking of crabgrass, in the photo below is a trial experiment using never before planted and I mean in the world planted "Round up Ready Ryegrass."
We are experimenting to see if we can establish a combination of Ryegrass and low mow Bluegrass on Tri City fairways as a means of creating better fairway playing conditions there. Once established, we should be able to remove and control all grass and broadleafed weeds with a single application of Round up at a low cost to the budget.