Are Weed & Feed Lawn Care Products Too Toxic to Use?
Combination Fertilizer/ Herbicide Products Banned in Canada
Companies specializing in chemical lawn-care products have long offered combination products that contain both fertilizers to feed the lawn and herbicides to kill crabgrass or broadleaf weeds. There are often marketed as time-saving products that allow a homeowner to accomplish both feeding and weed control in one action. Examples of these products include a variety of Scotts’ Weed & Feed Turfbuilder formulations, BioAdvanced’s Weed & Feed Fertilizer and Crabgrass Killer, Greenview’s Weed & Feed, Preen’s Weed Preventer and Plant Food, and Knox Weed/Feed.
What Is “Weed and Feed”?
Weed and Feed is a combination of fertilizer and broadleaf herbicide that is usually applied to lawn mid-season as a way to knock down weeds and feed the grass in one easy application. The fertilizer ratio can vary, but most popular brands usually feature a high nitrogen water-soluble fertilizer that encourages top growth. The vast majority of these products are in a granular form that is applied over the lawn with a broadcast spreader or drop spreader.
Limitations and Problems
Independent lawn experts see problems with weed and feed products on several fronts. First, the high nitrogen content stimulates top growth, but it does nothing to the overall health and vigor of the grass plants. All lawn fertilizers are somewhat nitrogen-heavy since deep green foliage is the goal, but a better fertilizer choice is one that is somewhat more balanced, offering at least some phosphorus to help the grass plants store and use nutrients, and some potassium to assist with root development.
The typical application time for weed and feed products, generally mid-summer is also not necessarily the best time to jolt your lawn with heavy feeding. Spring and early summer are much better times for major fertilizer application to a lawn.
The excess nitrogen found in weed and feed products can indeed leave you with an enviable, dark green lawn, but that grass will be extremely susceptible to drought. And excess nitrogen can lead to grub infestations and disease conditions.
But it is with the weed-control aspect of weed and feed products that the real trouble starts. The herbicide used is a powdered form of popular broadleaf herbicides that contain 2,4-D, mecoprop, and dicamba. This combination of chemicals is popular because it performs a lethal action on broadleaf weeds while leaving lawn grass unharmed. These products work by sticking onto the surface of the weeds, so conditions must be exactly right for the product to work. The lawn should be wet to allow the herbicide dust to stick to the leaves, but it is also important that rain is not forecasted; you don’t want to wash the product off the leaf before it has done its job. These precise optimal conditions can make proper application of weed and feed quite difficult, which often leads to misuse.
Banned in Canada
Combination products containing fertilizer and herbicide have been officially banned in Canada since 2010. Many provinces already had some legislation restricting the use of weed and feed or cosmetic herbicides, but the decision by Health Canada brought a total ban on the sale and use of the once-popular combination product.
The legislation concerning using weed and feed in Canada side-steps the most controversial aspects of using chemical herbicides—mainly the health concerns of long-term, repeated exposures—and goes for a more agronomic approach. Instead of entering the health controversy, the Canadian decision focused on the inefficiency of these products.
First, applying herbicide as a blanket application is not necessary. Weed and feed products spread herbicide to the far reaches of the lawn, whether there are weeds or not. Practices like this are out of touch with integrated pest management (IPM) and other, more sensible approaches to lawn care. Using herbicide where none is needed is excessive and not environmentally sound.
Another problem with combining the two products is that fertilizing the lawn and killing weeds on the lawn are best viewed as two separate events that should not be combined. Fertilizing the lawn should be done following your chosen lawn care regimen while eliminating weeds is its own practice and can be done more safely and more efficiently by spot spraying throughout the season.
Homeowners should consider the very real health risks that come with using any chemical herbicides, especially for children, pets, pregnant women, and the elderly.
Philip Landrigan, dean for global health and a professor of pediatrics at the Mount Sinai School of Medicine in New York, observes that because children grow quickly,
. they take into their bodies more of the pesticides that are in the food, water and air.
[Their] delicate developmental processes are easily disrupted by very small doses of toxic chemicals that would be virtually harmless for an adult.
Alternative Forms of Weed Control
If you must use chemical herbicides on a lawn, a far more responsible approach is to spot-treat weeds. Use a liquid spray product to coat the leaves of individual weeds when you spot them—doing this immediately after lawn-mowing chores is a good regimen.
And don’t discount the old-fashioned means of weed control—digging them out by hand. Especially in a small lawn, hand-removal of weeds is not a difficult chore, especially if you do it routinely so that major weed infestations cannot take root. A variety of helpful tools are available for lawn weed removal, ranging from long-handled forks to weed “poppers” that can remove the entire root. Weeding by hand also has the benefit of naturally aerating your lawn as you remove cores containing weed roots.
In some areas, any cosmetic use of herbicides—not just weed and feed—has been outlawed, and even spot-spraying weeds is not a viable alternative. A simple IPM program can help, along with a proper lawn care regimen. In any case, a strong argument could be made for looking into organic lawn care. Organic weed control takes a more holistic approach to weeds and sees their presence as a sign of other underlying problems. Many weeds invade when the grass is stressed or thin/bare turf is present. An aggressive over-seeding program can help, as well as mowing the lawn at heights of three inches or more. Some weeds—dandelions for example—tend to favor soils low in calcium, so a soil test and subsequent calcium applications may be a way to reduce their numbers. Ultimately, providing the optimum conditions for growing grass is the best way to control weeds.
Weed & feed products containing fertilizer and herbicide have environmental concerns that should be considered before you use them.
Weed and feed just feeds the weeds
April 21, 2017, 7:28 AM
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Mark in Stafford writes: “Every year I typically ‘wake up’ my lawn with a dose of weed and feed followed by another dose eight weeks later.
“But this year, because of the warm temps, I already have lots of dandelions and other weeds in my lawn.”
Don’t blame the warm weather, Mark. You have lots of dandelions and other weeds because you are relying on unreliable — and really unhealthy — chemicals instead of caring for your lawn correctly. The only thing those herbicides are killing are frogs, toads, earthworms and you.
Air: The long-term cure for dandelions
Dandelions are a sign of compacted soil, the long-term remedy for which is a “core aeration.” This is achieved by using a big noisy machine that pulls plugs out of the turf, allowing your grass roots more room to breathe. (And yes, plugs must be pulled; poking holes in the turf just … well, it just pokes holes in the turf.)
But don’t aerate now. Although it has great long-term benefits, core aeration stresses the lawn in the short term — and you do not want to stress a cool-season lawn with summer heat coming on fast. Although some people will try and sell you on the idea of doing it now, cool-season lawns of bluegrass and fescue should only be aerated in the early fall.
Hound Dog for the short term
But what about right now?
You can get rid of the most prominent of those dandelions with a simple mechanical device that pulls them out of the ground while you stand up (and it doesn’t leave nasty dead browned-out dandelions in the turf, as herbicides do). You just position the “puller” over the unwanted plant, step on a plunger and a small metal cage surrounds the dandelion and pops it up and out, root and all.
(And yes, because they are removing chunks of stuff, these devices do perform a little bit of gentle aeration as well. But it’s perfectly safe — much less stress than a big machine.)
The Hound Dog brand is probably the best known of these devices; it’s been around for many years. And a quick internet search will reveal dozens of similar devices under different names.
Be sharp; cut sharp!
Mark in Stafford double-doses his lawn with weed and feed and still has lots of weeds. So of course he asks: “Can I put down weed killer and a pre-emergent crab grass mix at the same time? Can you offer any advice?”
Yes I can, Mark — beginning with the advice to step away from your Spreader of Death, because you’re looking to drop your money on a sucker bet. The more toxins you toss on your turf, the more tattered it turns. The only way to reduce the number of weeds in your turf is to care for the grass correctly.
Step one: Get a new blade for your mower or get the old blade sharpened. A dull mower blade rips the blades of grass apart instead of cutting them cleanly. Those ripped-apart blades can’t store water and slowly die. Without healthy grass to hold the spot, weeds will inevitably move in. But when grass is cut cleanly, weeds don’t have a spot to seize.
Diet & exercise for a healthy lawn
Sorry, four-steppers, but the only way to truly control weeds is to care for your turf correctly. Yes: It’s boring, but it’s also shockingly effective — and inexpensive.
Now, back to Mark the Serial Weed and Feeder: No more food!
The cheap chemical salts in commercial “weed-and-feed” products are like fast food and fatty snacks; the unnaturally fast growth they cause is weak and easily overrun by weeds. And if Mark has already fed his lawn twice this season, he has almost certainly met or exceeded the legal limit for feeding lawns in Virginia (and Maryland). And it’s not just “the law”; it’s a common-sense attempt to try and save the beloved Chesapeake Bay from death by fertilizer.
Instead of buying more bags of fake pee (the main ingredient in many commercial lawn foods), sharpen your blade and raise the cutting height on your lawn mower so that the lawn is a solid 3 inches high after you cut it. Yes — after. Wait until the lawn reaches 4 inches high to mow, take off an inch with a sharp blade and the weeds will quickly diminish.
Yes, guys: Height does matter
Chalk it up to climate change or another weird winter, but there do seem to be a lot more dandelions around this year — especially in lawns that appear to be cut way too short.
News flash, guys: The blades of grass that make up a lawn are (gasp!) plants, and plants have needs that you cannot fulfill from a spreader or sprayer.
The biggest “cultural” need of turf grass (meaning something you can control, unlike the amount of sunlight) is height. Cut your grass lower than 3 inches, and it suddenly doesn’t have enough greenery to process sunlight effectively.
The grass goes into shock, draining any resources stored in its roots in a desperate attempt to grow some height back as fast as possible.
That’s right: The lower you cut, the more you’ll have to mow, because you’re forcing the grass to grow as fast as possible.
Cut at a height of 3 inches and the grass will grow as slowly as possible, now devoting its newfound extra energy to the root growth that crowds out weeds.
The dirty little secret of lawn care is that the only real cure for weeds is cultural, not chemical.
Send your garden questions to Mike!
Using chemicals just kills frogs, toads, earthworms and you. There are several things you can do to ensure weeds get off your lawn.