Fortunately there are ways to remove and prevent weeds without resorting to toxic chemicals. Read on to learn about simple ways to control your weed problem.
What’s in a Weed?
Ralph Waldo Emerson famously said that a weed is a plant whose virtues have never been discovered. Before plotting the downfall of the weeds in your lawn and garden, consider whether or not you’re attempting to eradicate something you can use. Chickweed makes a delicate garnish, while dandelion greens, miner’s lettuce, and edible purslane add a pleasant, tangy undertone to salads. Other weeds have medicinal uses, and it may be worth dedicating a small section of your yard for your herbal medicine chest.
Plants that truly don’t belong usually share the following things in common:
- Tenacity: They just keep coming back. This includes plants with deep taproots or those with a short life cycle that set seeds quickly and colonize the places where you’d rather grow something more beautiful or edible.
- Invasiveness: Japanese knotweed, kudzu, and morning glory (also known as bindweed) are some examples of plants that outcompete native species and take over quickly—and are difficult to remove.
- Toxicity: Poisonous plants are definitely something you don’t want in your vegetable patch. Nightshade, giant hogweed, buttercup and more are better off growing away from food plants.
Once you’ve decided which plants you want to eliminate, consider the following options.
Natural Weed Control: 10 Methods
1. Smother with mulch
A thick layer of mulch applied after hand weeding will prevent weeds from reseeding or emerging a second time. For shallow rooted weeds, mulching will smother plants and eventually kill off roots without hand weeding first, but you must make it thick. The best mulches are long lasting and organic. Apply thickly at 4 to 8 inches in depth. When in doubt, add more mulch.
Best Mulches for Weed Control
|Medium bark chips or chunks||Suppresses weeds well and has good resistance to wind and compaction. Best used in landscaping around trees, shrubs, and perennial plants, or on garden paths. Choose medium over fine to prevent weed growth. Also, ask at point of purchase to ensure source doesn't contain weed seeds.|
|Wood chips||Suppresses weeds well and is less expensive than bark mulch. Usually changes color over time (greys), so is also less decorative. Use as with bark mulch or chips.|
|Hulls or shells||A byproduct of agricultural crops (e.g. cocoa). Has a fine, decorative texture that makes it pleasing in landscaping. Usually lightweight and prone to blowing around in windy areas.|
|Leaves||Will hold back weeds when gathered and applied after fall. Tend to blow around and may need anchoring. Maple, birch, beech, and the leaves of fruit trees make ideal mulch.|
|Straw||Suppresses weeds well but may need to be held down by mesh or moistened with water to keep from blowing around in windy areas. May attract slugs during certain seasons. Extremely low cost when compared to other mulch, though not as decorative. Ideal for vegetable gardens (beds and paths) where it composts quickly, often in one season.|
|Grass clippings||Can suppress weeds adequately if piled thickly enough, though not as long lasting as straw. In hot areas, may form a temporary, impenetrable mat while decomposing, preventing crops from surfacing if applied before sprouting. If composting rapidly, may burn nearby plants. Use around woody shrubs, older plants, or use once dried. Usually free if you have lawn clippings, but watch for weed seeds.|
|Newspaper||Another low-cost option that suppresses weeds if layered. Less aesthetic than other options so often used under more attractive mulch. If used alone, needs anchoring or will blow away. May contain toxic metals or chlorine bleach that can build in soil over time. Consult your local paper about bleaching practices (oxygen vs. chlorine bleach) and avoid colored inks. Soy-based inks may also contain genetically modified ingredients, so assess this when researching local sources.|
For more mulch suggestions, read our article, Mulch Your Garden to Beat the Heat.
2. Limit disturbance
The less you turn and disturb your soil, the less likely you are to have weeds reseeding in your garden. No-till gardening is popular for this reason, since it keeps dormant weed seeds below the surface of the soil indefinitely, reducing the weeds you do have to manage to those transported by wind, birds, and shoes.
If you do till your soil, plan the disturbance for a time when the trees and perennial plants in your area aren’t filling the surrounding air with seeds and when your soil is dry. Better yet, combine no-till methods like mulching in fall with building up your soil via compost and other organic matter in the spring so that tilling becomes unnecessary. For more information, read 5 Secrets to a No-Work Garden.
3. Cover with landscape fabric
Landscape fabric prevents weeds from taking root by blocking the soil from weed seeds. Since it’s not attractive to look at, it’s designed to sit under a layer of organic mulch, which also protects the fabric from the sun’s rays and extends its lifespan. Unfortunately, the organic mulch will eventually provide weed seeds with good growing conditions and you’ll find yourself weeding on top of your landscape fabric instead of beneath it. Thankfully the landscape fabric blocks roots from penetrating the soil below, which makes hand weeding these areas quick and easy. Landscape fabric is most commonly used on garden pathways or around perennial plants, shrubs, and fruits for best results.
Landscape fabric will smother invasive weeds, as long as the fabric is wide enough to prevent the plant from crossing beneath this barrier. Filter fabric is a thicker variety of landscape fabric that comes in large widths and works well as a weed barrier. To kill weeds in the off-season, HDPE is another option that blocks sun and water. Keep in mind that most landscape fabrics are made from petroleum products and are best used for short-term weed control to avoid introducing plastics to the soil. Long-term use of landscape fabrics may also compact the soil and prevent you from adding important amendments like compost and other fertilizers.
4. Plant ground covers
Weeds thrive by gaining a foothold and outcompeting more desirable garden plants. Beat them at their own game by planting a ground cover that does well in your area and rapidly fills in exposed soil. Quick-growing ground covers like white clover won’t only reclaim an area, they can also add nutrients to the soil and hold a bed until you’re ready to plant or landscape. Others like barley, oats, wheat, rye, and canola produce compounds that inhibit the growth of other plants. Ground covers worth considering include those noted below.
Common Ground Covers and Their Uses
|Clover||Full sun, dappled shade.||As a lawn replacement, green manure, or between garden beds to add nitrogen to the soil. Contains alleopathic (weed inhibiting) compounds.|
|Barley, oats, rye, wheat, fescues, hairy vetch, perennial ryegrass, buckwheat.||Full sun||For short-term weed control. Produce alleochemicals that inhibit the growth of nearby plants.|
|Chamomile||Full sun, dappled shade.||Use European chamomile (Chamaemelum nobile) as a lawn replacement.|
|Woolly thyme||Full sun, partial shade||Around patio bricks and stepping stones|
|Rock rose||Full sun||In sunny edges along lawns or borders and beds.|
|Anemones||Light shade||Around perennials, shrubs, and along walkways.|
|Sweet woodruff||Full to partial shade||In borders, around shrubs and trees, and in swaths along lawns.|
|Hebe||Sun or partial shade.||In landscaping around larger shrubs and trees. The variety Hebe pagei spreads to form a low growing mat with delicate white flowers that bloom in spring and summer.|
|Kinnikinnick||Full sun, partial shade.||On steep banks and in other hard-to-grow areas. Will grow in poor, dry soil once established but needs adequate drainage. Extremely drought tolerant.|
|Sedum||Full sun||Low-growing species in sunny areas with well-drained soil.|
5. Take advantage of the sun
Use the sun’s heating power to scorch weeds and render them dead. Start by trimming the area to be solarized with your lawn mower or hand shears. Cut as close as possible to the ground and thoroughly soak with water. Next, cover the area with a sheet of clear plastic—a leftover drop sheet from painting works well. Spread the plastic beyond the edges of the area to be solarized and anchor with landscaping staples or rocks every three feet. Seal edges by burying or tucking into trench for best results.
After the area has turned brown, let the plastic sit another one to two weeks. The total time this process will take depends on the amount of sun you receive and the heat it can generate beneath the plastic sheeting. In most cases, the weeds will die off within six to eight weeks.
6. Apply corn gluten
Corn gluten is a byproduct of the corn milling process that stops weeds from forming a root during germination. Weeds treated with corn gluten form only a shoot, and with limited water following application, will eventually shrivel die. Corn gluten doesn’t work on already existing weeds (unless applied at very high concentrations), so it’s best applied early in the season as a weed preventative. Use 20 to 40 pounds per 1500 square feet. You can apply again in the fall to extend its preventative powers. As an added bonus, corn gluten also works as a fertilizer, helping to develop strong turf in backyard lawns. For more information about using corn gluten to prevent weeds, read our article Corn Gluten Meal.
7. Spray with DIY or natural weed killers
This may sound like a chip flavor, but a salt and vinegar solution kills some weeds when mixed with a few drops of liquid dish soap for adhesion. Salt works by dehydrating the plant, but it will kill surrounding plants, too, so use only in areas where you don’t want anything to grow period (on driveways, walkways, or in sidewalk cracks, though woolly thyme is preferable—see above). Too much salt isn’t good for soil, pets, or wildlife, so target only plants that don’t respond to other methods by using a garden sprayer and dousing selectively. Start with a low concentration and work upwards as needed.
Another natural weed killer is Burn Out, a weed and grass killer that uses citric acid and clove oil as its active ingredients. This non-toxic alternative to killing weeds is good for spot treatments on lawns, flowerbeds, and vegetable gardens. Deep-rooted weeds may require multiple applications and the product is best used for spring or early summer applications.
8. Flame weed
Rather than trying to burn up individual plants, flame weeding scorches the plants’ crowns just enough to cause tissues to shrivel and die. This means that flame weeding doesn’t kill a plants’ roots immediately. Instead it causes the tops to die back just enough to deprive the roots of energy. While this method generally works best on annual weeds, you can also kill deep-rooted, perennial weeds (like thistles and dandelions) by scorching the plant when the weeds first emerge (when they have their first pair of leaves), and one or two times after that.
Take care not to get too close to the ground with your flamer. Overheating the ground can kill desirable plants growing nearby and friendly microbes in the soil. Instead, scorch the crowns of weeds quickly—1/10 of a second is enough. Use only during seasons of low fire danger and after a rain, or during periods of high morning dew. Sprinkle weeded areas with water afterwards to ensure safe usage. Flame weeding is effective on walkways or patio cracks.
9. Use poultry
Chickens and ducks are natural weeders and live to scratch, nudge, and turn soil over to find what lays beneath. Half a dozen chickens contained on a stretch of unwanted weeds will quickly rid the area of plants and roots, leaving soil exposed and ready for planting. Ducks will dabble vigorously in moist, springtime gardens to find slugs, shoots, and tender weeds. Control by using a covered pen that you can move around to target desired areas, keeping in mind that your birds won’t distinguish between the plants you want and the ones you don’t.
10. Dig by hand
Digging by hand is the first and best line of defence for most weeds. When combined with the other methods in this list, it’s usually a surefire way to keep weeds at bay or eradicate them entirely from an area. The key when removing weeds by hand is to get all the plant’s roots, particularly if you’re dealing with tenacious rhizomes or taproots. Use a sturdy tool designed for working deeply or in difficult areas. Repeated digging sessions will usually challenge even the most persistent plants.
Avoid placing invasive weeds in your compost after removing from the garden—unless you know your compost heats up hot enough to kill weed seeds. Otherwise, these tenacious plants will survive and thrive, spreading all over again.