Follow these tips to defend your turf from crabgrass and be one step closer to having a perfect lawn.
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Get Them Before They Sprout
FAMILY HANDYMAN
Get Them Before They Sprout
The best weapon you have against this annual weed is crabgrass preemergence herbicide (also called crabgrass preventer). You apply this product in the spring before the crabgrass seed sprouts. The most cost-effective way to apply a preemergent herbicide is to use a fertilizer with crabgrass preventer added to it. Apply it when you would normally apply your first application of fertilizer, and do it just before it rains to work both the fertilizer and the herbicide into the soil.
The fertilizer will help thicken the turf. Thicker turf helps to squeeze out crabgrass plants missed by the herbicide. Common brands include Ferti- Lome’s Weed-Out, Sta-Green’s Crab-Ex Plus and Scotts Turf Builder.
So how do you select the exact instant for application? Pay attention to your grass. Fill up the spreader with preemergence granules between the second and third mowings of the year. The window is short, only about a week and a half, when the soil hits the ideal temperature, about 52 degrees F. You can also buy an inexpensive soil thermometer (sold at garden centers) to monitor soil temperature. If you’re going to err on timing your crabgrass preemergence application, err on the early side.
While you’ll lose some effectiveness, you’ll still probably kill lots of crabgrass. If you go late, you’re likely to miss early sprouts.
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Crabgrass Killer Application
FAMILY HANDYMAN
Crabgrass Killer Application
Apply crabgrass preemergence granules with a spreader, especially around driveways and walks and also alongside the neighbor’s crabgrass-infested yard.
Herbicides that kill crabgrass will also kill desirable grasses such as bluegrass, ryegrass and fescue. If you treat your lawn with a preemergent, you cannot seed. And if you seed, you cannot use a preemergent herbicide. The solution is to control crabgrass in the spring and do your seeding in late summer or early fall, making sure to keep these two chores at least eight weeks apart. There are a few preemergent herbicides, such as Tupersan, that are compatible with newly established seed, but they’re expensive and can be hard to find.
There are many different trade names for ‘weed and feed’ products on the market. Chemical names can be confusing. Look carefully at the ingredients panel for dithiopyr, prodiamine or pendimethalin. These active ingredients, which are sold under various brand names such as Dimension, Barricade and Scotts Halts, will kill crabgrass in most areas of the country and in many different kinds of turf. However, it’s always wise to ask your local extension service which chemicals are best for your area and turf species.
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What To Look For
FAMILY HANDYMAN
What to Look For
Young crabgrass plants perfect for pulling have two to four sets of leaves but no splayed seed heads. Immature crabgrass plants have tight, green seed heads. They’re more difficult to remove, but it’s still OK to pull them.
