Is Weed and Feed Bad for Your Lawn?

Man spraying weed killer on his lawn

Talk about a loaded question. Whether weed and feed is bad or good for your lawn depends on several factors. 

Weed and feed is a convenient product that does at least two lawn maintenance tasks at once. However, what concerns come with use of weed and feed for your lawn? Is it always necessary? This article looks at the pros and cons to help you decide whether to use weed and feed on your lawn.

What is weed and feed?

Weed and feed is a granular or liquid product that performs two functions when applied to the lawn: it kills weeds and fertilizes the lawn. There are weed and feeds formulated for spring application and weed and feeds formulated for fall.

4 benefits of weed and feed

Man spraying weed killer on his lawn
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1. Two tasks completed at once

Weed and feed products score high on the convenience scale with homeowners for weed control and fertilizing. A couple of passes with a spreader or sprayer in spring, and you control some weeds while fertilizing the lawn. 

2. No mixing or measuring

Weed and feeds are popular among homeowners and landscape maintenance crews because the product is ready to use. The only measuring is knowing your square footage and setting the weed and feed applicator per the instructions on the product label. 

3. Kills various lawn weeds

Not only is weed and feed an easy 2-in-1 application, but it also delivers effective control against several weed types. Dividing your weed control and fertilization chores into two separate treatments will also provide effective weed control, but some lawn owners may find this approach inconvenient. 

Herbicides in weed and feed products are either post-emergent or pre-emergent weed killers or both. Post-emergent herbicides kill existing weeds in the lawn, while pre-emergents prevent weed seeds from germinating. 

4. Fertilizes the lawn

Spreading weed and feed across the lawn is like feeding two birds with one scone. Not only does it provide effective weed control, but the fertilizer also packs a punch. 

Fertilizers in many weed and feed products are available in either slow-release or fast-release forms. Fast-release fertilizer, also called water-soluble fertilizer, releases nutrients quickly for a fast green-up. Slow-release fertilizer, or water-insoluble fertilizer, releases nutrients slowly for up to three months. 

7 concerns about weed and feed

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1.  Poor timing

Although weed and feeds are convenient, they may not always be what’s best for the lawn and the environment. For instance, timing with the combined product can be problematic.

Most weed and feeds miss the timing mark because of their formulation. As with other 2-in-1 products, such as one that cleans and waxes the car in one step, the results might not be as good as washing the car, followed by waxing the car separately. 

Because of how weed and feeds are formulated, you apply both products to the lawn whether you need them or not. For instance, you may have weeds in spring, but you may not have to use a lawn fertilizer, especially if it was fertilized in fall. Fertilizing in spring increases mowing duties, and your grass might already be healthy without it. 

Here’s another example: You may have existing autumn weeds in the lawn. Post-emergent herbicides in weed and feed will kill the existing weeds, but a dose of fertilizer in fall might prove harmful to your warm-season turf

2. Excessive chemical use

If you don’t have a lot of lawn weeds, applying weed and feed all over the lawn encourages the overuse of herbicides. If a few spots of lawn weeds concern you, consider applying a separate herbicide labeled for those plants. That way, there’s no need to treat the whole lawn for just a spot or two of weeds.

3. Environmental concerns

Overusing chemicals in the lawn, such as using weed and feed for a few spring weeds in a lawn that was already fertilized last fall, puts fertilizers and herbicides in the environment unnecessarily. This increases polluted runoff into rivers and streams during rain storms, snowfalls, or irrigation. 

These products also interfere with soil health, possibly taking a toll on beneficial insects and microorganisms. There also are concerns about the possible toxic effect the weed and feed could have on wildlife.

Labels warn against using weed and feed products near lakes, streams, creeks and other waterways because of toxicity to aquatic life.

4. Pets on treated lawns

Dogs lick their paws and cats constantly clean their fur. These traits increase the possibility that pets may ingest weed and feed they pick up on their treks outdoors. 

Keep in mind that your pets’ exposure to chemicals still holds true for many lawn and garden products besides weed and feeds. However, because weed and feed may lead to a high dose of chemicals on the lawn, your pets’ exposure to these chemicals may increase. 

5. Concerns about drift

Drift is a major concern, especially when using liquid weed and feed on the lawn. It’s easy, with just the slightest wind, for the weed killer to drift onto desirable perennials and other plants. 

A post-emergent weed killer does not recognize the difference between the dandelion and the nearby coneflower and will kill both. Herbicide drift can also kill or harm trees and shrubs. 

Again, this risk holds true for any herbicide, but may increase with weed and feed. 

6. Tracking dangerous chemicals indoors

Even if you avoid walking on the lawn after applying weed and feed, your shoes may still pick up the chemicals and bring them indoors. Removing shoes outdoors reduces that risk. Tracking outdoor chemicals indoors is a risk with any lawn and garden product.

7. Necessary or cosmetic?

Weed and feed falls into the routine of lawn care, primarily as a cosmetic concern. But is the repeated application of weed and feed really needed on a healthy lawn? Sometimes, convenient products are used because of habit rather than necessity.

Always read the label

The weed and feed label has a wealth of information about the product and how to use it. These products are regulated by the Environmental Protection Agency, which requires users to read  and follow the label directions.

  • Before buying any lawn product, know what kind of turf you have. Weed and feed labels list the types of grasses on which the product can be used. Products for cool-season Kentucky bluegrass won’t work for warm-season St. Augustine turf, for instance.
  • Labels list which weeds the product will kill or prevent from sprouting.
  • Labels give information on which fertilizers, including types of nitrogen, are in the mix.
  • Labels note the best times for application of the product, such as ambient temperature, whether the lawn should be dry or wet and timing of anticipated rainfall. 
  • Labels emphasize special care when applying, such as keeping it away from water. It also tells how long after application people and pets can get on the lawn.

Tip: Don’t sow grass seed when applying a pre-emergent herbicide on the lawn. This herbicide doesn’t distinguish between a weed seed and a grass seed and will keep each from germinating. The product label tells you when grass seed can be son safely.

Weed and feed alternatives

Just like sports, the best defense is a good offense. A healthy lawn is the best defense. That means putting your lawn on a maintenance plan that includes separate applications of fertilizers and herbicides at the correct times for your area. Your county extension service will have recommended dates for lawn maintenance steps for a healthy green lawn.

Separate fertilizers and herbicides

Rather than using weed and feed, develop a plan that includes applications of fertilizers and weed killers separately and at the correct time. The products’ labels give directions on how and when to use them. 

Yes, it could mean making two treks around the lawn rather than one, but you’ll know you’re applying the right products at the right time, making them the most effective without any waste.

Organic fertilizers

There are several organic and natural lawn care products available if you’d rather not use synthetic chemical fertilizers on your lawn. These are primarily slow-release, water-insoluble fertilizers. Products that carry the OMRI label (Organic Materials Review Institute) means every ingredient is organic. 

Man on riding lawn mower mulching leaves as he cuts his grass
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Mulch your leaves

If you mulch your leaves with your mower in fall, you can reduce at least one application of fertilizer. The leaves, chopped into tiny bits, decompose to add organic matter to the soil. A couple of passes with a mulching mower (most mowers mulch these days) takes care of the leaves. Even having to do a repeat a few weeks later is still less work than raking, bagging and carting to the curb for pickup.

Vacuum your leaves

You can also mulch and vacuum the leaves. Mowers and other lawn equipment frequently come with bags to hold the vacuumed leaves. This produces probably one of the best mulches for any garden. 

As organic matter, chopped leaves are particularly valuable in fall as a soil cover and natural conditioner for bare soil, such as the vegetable garden. Mix in the soil when making new beds to help with drainage. The leaves also can be added as mulch around perennials, trees and shrubs.

Mow high 

This is the first line of defense for developing a good offense to ward off weeds. Grass in the 3-inch-high range shades the soil, cools grass roots, keeps weeds from taking hold, and improves lawn health. Don’t remove more than one-third of the blade at any one time. For example, if the grass is 3 inches high, don’t remove more than 1 inch.

Aerate the lawn

Aerating opens up the lawn with small holes, making it easier for water and other nutrients to reach the roots. Perform this task every couple of years in fall if you grow cool-season grass or summer if you grow warm-season grass. Foot traffic, such as where the mail person walks every day, and play areas compact the soil, which impedes lawn root development.

Take quick action on weeds

If you have just a few weeds in your lawn, try to remove them before they flower and set seed. Keeping weeds from seeding goes a long way to reducing weeds in your lawn (and garden beds). Rather than treating the whole lawn, consider spot spraying with the appropriate herbicide. As a DIYer, read the label to know what you are buying, how to use it and for what. Always read and follow the label directions.

When to call a lawn care pro

If you’d rather not deal with weed and feed fertilizers or separate applications of herbicides and fertilizers, call Lawn Love and let one of our nearby pros handle keeping your lawn healthy and weed-free.

Main Photo Credit: iStock photo with text overlay

Jo Ellen Meyers Sharp

Jo Ellen Meyers Sharp award-winning garden writer, editor, and speaker. (She speaks at libraries, garden clubs, public gardens, home and garden shows, Master Gardener groups, and horticulture industry events.) Known as a hortiholic, she frequently says her eyes are too big for her yard. She blogs at hoosiergardener.com.