What is Crabgrass?
Crabgrass has an annual life cycle, which means any crabgrass present in lawns last year is dead, and the only way for crabgrass to appear this year is by seeds germinating into new plants. Crabgrass seed will start to germinate when soil temperatures get close to 55 degrees F and stay there for several consecutive days. Crabgrass likes full sun, thinner lawns, nutrient imbalance and frequent watering.
Proper Lawn Care Practices
Keeping those preferences in mind, improved lawn care practices can have a major impact on reducing or eliminating the chances of crabgrass appearing in your lawn. Mowing height is the number one mistake a homeowner can make. Mow between 3.5 and 4 inches, or higher, and there will be fewer crabgrass plants in your lawn. Frequent watering of lawns also favors crabgrass, so follow the general rule of deep, infrequent watering for your lawn. If you set your sprinkler system at the beginning of the year, and forget about it the rest of the year, you are probably watering improperly. As seasons change so should the settings on your sprinkler system. Crabgrass often invades areas seeded in late spring because of bare soil, frequent watering, and onset of hot weather which is ideal for growth. We recommend seeding in the fall if your yard is thin in conjunction with aeration and any soil test recommendations.
Organic or traditional pre-emergent can also be used in spring for crabgrass control. These products need to be applied to the lawn before crabgrass germinates. Late April into early May is the suggested time for applying pre-emergent crabgrass products. If April is unusually warm, apply by late April; otherwise early May is not too late. Corn gluten is a great natural pre-emergent but it’s only about 70 percent effective. It’s probably a better fertilizer then pre-emergent but 70 percent is better than zero.
Most pre-emergent crabgrass products are found as a combination with lawn fertilizer so the crabgrass prevention and spring fertilization can be done at the same time. Following the rates given on the bag is always recommended.
One of the management problems associated with pre-emergent products is seeding or overseeding practices. With the exception of a synthetic herbicide called Siduron, all pre-emergent will damage germinating desirable grass seed.
Crabgrass is much easier to prevent then it is to control, once its growing, so planning ahead is you best option.
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