Seasonal Solutions - Innovative Seasonal Products
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06/04/2007 12:23 PM
Controlling Crabgrass in the Lawn
Crabgrass is a native summer annual grass species, sprouting
from seed each spring and dying in the fall. As such it is well
adapted to survival in lawns. The seed are capable of laying
dormant in the soil for up to 15 years, waiting for conditions to
become right for sprouting and growth.
Annuals depend on their seed for the survival of the species.
These seed will lay dormant in the soil until the ground warms
in the spring. Crabgrass seeds normally begin germinating at
the same time that dogwoods and forsythia bloom. They will germinate all during the summer
wherever sunlight hits bare ground.
The best defense is to insure that no bare ground exists in the lawn after the weed(s) begin their
spring blooming. This is best accomplished by practicing good lawn management in the fall,
namely by removing any live or dormant crabgrass and replacing it with grass seed or plugs. Leaves
should be removed in a timely manner, the lawn fertilized and limed according to soil test.
Nematodes should be applied between mid-June and mid-October to control grubs of the Japanese
Beetle and the Green June Beetle.
The first spring after reseeding the lawn should be mowed no closer than four inches high to
increase the shading effect. The lawn must be maintained for
optimal growth but not over fertilized. Over fertilization can
result in a rank spring growth of the lawn grasses which will
make them more prone to foliar diseases. Diseases which result
in bare spots or thinned stands will actually encourage the
establishment of crabgrass.
Crabgrass preventative herbicides work by inhibiting the
germination of the crabgrass seed. Since they will also inhibit
the germination of lawn grass seed, they can not be used on
lawns seeded in the spring. Even if the lawn is seeded early in the spring the herbicides will be
damaging to the newly emerged l