Crabgrass can be one of the most visible – pesky issue for your lawn. Crabgrass is an annual, which simply means that it self seeds itself on a yearly basis. It is also a warm weather crop. This is important in the fight against an invasion. Our typical turf-grass in Massachusetts are cool weather crops. The Fescues, Bluegrass and Rye-grass typical to our lawns do really well in Spring and even better in Fall, while they can actually go into heat dormancy over the summer depending upon how hot and dry our season is. Crabgrass on the other hand thrives in the dry heat. For germination, the soil temperature needs to be above 58 degrees for approximately one week. The recent summer temperatures did in fact start the process of germination for the crabgrass, but in most cases this cool weather has slowed the process down.
The best prevention of Crabgrass is to have a healthy thick turf. This should be done with a comprehensive IPM (Integrated Pest Management) approach. You would start with simple cultural practices- Cutting the lawn at a proper height, keeping trees properly pruned to allow enough light, keeping the turf aerated, top dressing with compost/ organic matter and or sand. The turf system also needs nutrients- organic tea, synthetic fertilizer, or organic based fertilizer. And of course a healthy lawn needs water.
If you can keep your lawn thick and healthy with cultural practices, nutrients and adequate water, crabgrass will typically not be an issue. If however your lawn is stressed by excessive heat, cutting it to short, improper watering then crabgrass can and will be an issue.
This process is of course easy in theory, but it typically takes a concerted effort to acheive. As always, if we can help give us a shout, if this has helped already, tell your friends!