A single weed can produce as many as 250,000 seeds. Though some seeds are viable for only a year, others can lie dormant for decades, just waiting for their chance to grow. When they’re buried several inches deep, the lack of light keeps them from germinating. But bring weeds to the surface, and they’ll germinate right along with your flower and vegetable seeds.
Even if you’re diligent at hoeing and pulling weeds, more seeds arrive—by air, by water runoff, and in bird droppings. You may accidentally introduce weeds by bringing seeds in on your shoes, clothing, or equipment or in the soil surrounding the roots of container-grown stock.
If you had more weeds then seedlings last year or are already feeling defeated by the number of weeds choking out your favorite plants, don’t worry! These surefire tips will help you keep down weed populations during the growing season:
Before you can determine your best defense strategy against weeds, you need to know what you’re up against. Some weeds, such as miner’s lettuce, chickweed, purslane, and dozens of grasses, are shallow-rooted annuals. Others, such as dock, comfrey, thistles, and certain runner grasses, are deep-rooted perennials. The two types require different control methods. Arm yourself with a good field guide, then identify and inventory your weeds. After that, you can ...
Photo: (cc) Dawn Endico/Flickr
Wait for the weather to be hot and dry for several days, then attack young annual weeds with a rake, hoe, or trowel. That way, the drought-stressed weeds are sure to shrivel and die, even if your cultivation doesn't remove the entire root of the plant.
Photo: (cc) John Tann/Flickr
The long taproots of perennial weeds cannot be pulled out when the soil is dry. To remove these weeds, wait for wet soil—either from rainfall or from your hose. If the soil is wet and loose, even pesky thistles should come out with their roots intact—which means they won't grow back!
Photo: (cc) Lazurite/Flickr
If invasive grasses, such as Johnsongrass or bermudagrass, threaten your garden, use a pitchfork to “comb” your beds before you plant in spring, suggests an Organic Gardening reader. Work the soil until it’s sufficiently loose for planting, then go over the entire area with a pitchfork, stabbing into the ground and levering it back toward the soil’s surface. The tines of the fork will catch any buried grass roots, which you can then remove by hand. This technique has removed about 90 percent of the grasses from a reader’s market garden in Texas.
Photo: (cc) Con O'Brien
Deprive weeds of the light they need by covering bare soil with a thick layer of grass clippings, shredded leaves, pine needles, or other organic mulch. Any survivors that do manage to penetrate the mulch usually are so weak that you can easily remove them by hand.
If you’ve got a large-scale weed problem, bake the plants beneath a sheet of clear plastic. For best results, wet the soil before you cover it with the plastic. Leave the plastic in place for at least 3 weeks—ideally, when the weather is hot and sunny. This method is especially effective against cool-season weeds and annual grasses.
Peas and other shallow-rooted crops can be damaged easily by cultivating the surrounding soil. That's why broad-leaved weeds can easily overtake them. So why not establish an edible, living mulch to fight the weeds and provide an extra early-season crop? Sow seeds of a fast-growing leaf lettuce thickly between young pea plants. The lettuce will outperform the weeds, and you can harvest the lettuce thinnings as you pick your peas.
Photo: (cc) Buck/Flickr
If you're faced with a pugnacious patch of pigweed, fight back by planting a mixture of squash and buckwheat. The vigorous squash and quick-growing buckwheat will easily overtake the weeds. At the end of the season, harvest the squash, pull out the vines, and turn under the buckwheat. The buckwheat will add organic matter and nutrients to the soil for next year's crops.
Photo: (cc) PawPaw67/Flickr
Use strawberries to smother weeds! These perennial fruits spread by runners and are vigorous enough to overcome many weeds—even in light shade. In mild-winter areas, such as Zone 9, they'll grow (and hold off weeds) all year long. Try growing them as a groundcover beneath blueberries and roses.
Photo: (cc) Amanda Slater/Flickr
In Maine’s chilly Zone 5, organic market gardener Eliot Coleman uses a tiller to battle redroot pigweed, the seeds of which can remain viable in the soil for years. Coleman runs the tiller through his beds as early as possible in spring to bring the weed seeds closer to the soil’s surface, where they can germinate. That’s right: Coleman encourages the weed seeds to sprout! Then, a week or two later, he tills a second time to clear the area of the young weeds before he plants his vegetables.
Photo: (cc) Pawel Loj
Keep Reading: 8 Weeds You Can Eat!