Weed-control products can play a key role in keeping a lid on lawn weed problems, but they’re not magic potions that make weeds go away forever in a single application.

You’ll get the best results from any product by making sure you’re using the right weed control in the right situation and by applying it in the right way at the right time.

1. Are you trying to kill weeds or prevent new ones? 

Weed-killers or “herbicides” are sprays or granular products designed to kill existing weeds, but they generally don’t stop new ones from sprouting.

Weed-preventers, on the other hand, are granular products designed to stop the growth of new weeds from seeds, but they don’t kill existing ones.

That’s important to know when buying because you’ll need a crabgrass preventer if your goal is to prevent a new outbreak of crabgrass or foxtail but a lawn herbicide or “weed-and-feed” if your goal is to kill existing dandelions, chickweed, and henbit.

Both types of products can be used if your goal is to do both, and some combination products do both functions in a single bag. GreenView Fairway Formula Spring Fertilizer Weed and Feed and Crabgrass Preventer, for example, is a three-function product that fertilizes lawns, prevents new grassy weeds, and kills most broadleaf weeds without harming turfgrass.


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2. What kind of weeds do you have? 

Not all herbicides kill all weeds. Some are “selective” ones that kill broadleaf weeds but not grassy ones, or vice versa.

Other herbicides are “non-selective,” meaning they’ll kill just about anything green. If you spray one of those on dandelions on the lawn, you’ll kill both the dandelions and the surrounding turfgrass.

Similarly, weed preventers also don’t prevent all kinds of weeds. Check the label to make sure the weeds you’re trying to head off are listed.

3. Apply products at the right time

When you apply a product is important, especially for weed-preventers. These need to be in place before weed seeds germinate (and in some cases, within a short time afterward) for the product to work.

Lawn crabgrass preventers, for example, need to go down in early spring – around the time forsythia bushes bloom – to stop the main first crop of new crabgrass from sprouting. If you miss that window and give young crabgrass plants a few weeks to grow, a later application won’t affect that outbreak.  

Read more on how to deal with crabgrass on the lawn

Lawn weed-killers are most effective when weeds are actively growing, but they can harm turfgrass if applied in very hot weather or when the lawn is drought-stressed.

Spring and fall are the best times to apply lawn weed prevention and weed killer products.

4. Apply products the right way. 

How you apply a product also can make a big difference in how well it works.

Granular weed-killers, for example, work best when they’re applied to wet grass. The granules stick better to the blades after a rain or in the morning dew.

Spray-on herbicides can be used on damp or dry grass, but they shouldn’t be applied if rain is expected within 24 hours. Drenchings will wash off the herbicide before it’s had a chance to be fully absorbed. (Also don’t irrigate the lawn until at least 24 hours after spraying.)

Above all, apply the prescribed amount. More is not better. Mixing sprays extra strong or putting down more granular product than necessary could harm the grass and runoff into waterways.

Reading lawn product label

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5. Read the label! 

Product labels go into detail about all of the above, plus offer other important instructions, such as how to safely use the product and how to safely store it if any goes unused.

If your lawn has weed trouble year in and year out, that’s a sign that your lawn isn’t as dense or as healthy as it should be. Weeds are opportunistic growers that have a much harder time invading a thickly growing lawn.

Well-timed fertilizers and overseeding thin lawns are two other ways to discourage lawn weeds without having to resort to weed-control products.

Read more on how to choose the right lawn fertilizer

See GreenView’s Fairway Formula lineup of lawn fertilizers

Read more on how to overseed a lawn

See GreenView’s lineup of Fairway Formula grass seeds