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It’s great to get out in the garden again, but what about the weeds that beat you to it? Before picking up a synthetic herbicide, try one of these inexpensive, safe techniques.
Of course, you’ll stay a step ahead of weeds by pulling them as soon as they appear. Pounce after a rain, when the ground is soft and it’s easy to pull out the entire root. Weeding tools help pry out deep roots.
To supplement hand weeding, here are 10 weed killers you’ll find around the house. Depending on the weed and the method, you may need to treat weeds more than once.
Pour boiling water directly on weeds. This kills many within a few days. It’s an especially good technique for hard-to-extract weeds growing in cracks and between pavers.
“When I boil potatoes or pasta during the gardening season, I repurpose the boiling water by draining the pot directly onto the weeds that like to invade my backyard herb garden and patio,” writes Jeff Yeager at Good Housekeeping.
Crabgrass is the sworn enemy of many homeowners. It infests lawns and, even if you are willing to use a chemical treatment, often what kills the crabgrass also kills the lawn. Lawn fertilizers encourage crabgrass. The way to push it out is to keep your lawn healthy, lush and a bit longer than usual, says the Yard MD blog:
There are no expensive products or chemicals needed to do this; simple common sense will do. This means to keep your grass at least three to four inches high and change your attitude about the “need” for a short or scalped lawn. Those conditions invite crabgrass and allow it to thrive because they allow light to reach the unsprouted seeds.
3. Smothering and mulching
Covering the ground with heavy black or opaque plastic kills weeds by depriving them of light and moisture. Use old tarps, shower curtains and heavy plastic used to package electronics. Plastic is a type of inorganic mulch. Others include stones, gravel and landscape fabric.
Organic mulches don’t usually kill weeds; they prevent them from germinating. You have to pre-weed and then apply a thick layer of weed-seed-free mulch like shredded bark, wood chips, straw, compost, leaves, pine needles and lawn clippings. The mulch breaks down, enriching the soil and helping reduce evaporation.
Only with really heavy organic materials can you dispense with weeding. Some gardeners place layers of wet newspaper, flattened wet cardboard, carpet scraps and even old jeans on top of weeds and cover everything with a layer of mulch. It all eventually breaks down and becomes soil.
Clear plastic works faster than other types of plastic by using the sun’s heat to cook weeds. The Christian Science Monitor tells how:
The process, which is called solarization, uses the heat of the sun’s rays to literally cook plants, weed seeds, nematodes, insects, and soil pathogens (the “bad guy” fungi, bacteria, etc. that bring diseases to plants) in the uppermost layers of soil. It also makes nutrients more available to plants later grown in solarized soil.
Spray distilled white household vinegar (with 5 percent acidity) directly on weeds. If necessary, a stronger concentration can be purchased at garden stores. Vinegar kills any plant you spray, so be careful.
Treat weeds in the middle of a warm day for a boost from the sun’s heat. Use a spray bottle with a nozzle that has a pinpoint setting. Spray on windless days to avoid contaminating other plants. HGTV suggests adding a tablespoon of dish detergent and two tablespoons of vegetable oil per gallon of vinegar to help it stick to plants.
MSN Real Estate says a 50-50 vinegar-water solution works too: “This is a good method for attacking unwanted plants with long taproots, such as dandelions, dock and plantain.” About.com has more on using vinegar in the garden.
Vinegar’s acetic acid breaks down in water, so it won’t harm soil. Treat weeds when the ground is dry for the best effect.
You can use a light-duty household propane torch to kill weeds. “You don’t need to actually set weeds on fire to kill them; quickly running a flame over them will usually cause them to wilt and die within days,” says Good Housekeeping.
Butane kitchen torches have a wimpier flame, but eHow says gardening author Sharon Lovejoy, in “Trowel and Error,” describes using her kitchen torch to kill weeds by passing it over them for a few seconds.
“One person’s weed-filled lawn is another person’s salad bar,” says Organic Gardening magazine, explaining how to identify and eat eight weeds. I’m not suggesting eating as your only eradication technique. But when the garden gives you free food that’s full of antioxidant vitamins and omega-3 fatty acids, why not say, “Pass the purslane, please?”
Among the many edible weeds, Good Housekeeping and Organic Gardening recommend dandelion greens, purslane, bamboo shoots, Japanese knotweed, lamb’s quarters, kudzu, red clover, garlic grass, plantain, sorrel, chickweed and burdock. Pick greens when they’re young, tender and mild tasting.
Wild watercress is edible but it can be associated with the dangerous liver fluke parasite, so it’s best avoided.
At HGTV Gardens, forager Steve Brill explains how to pick and eat chickweed. Mother Nature Network has harvesting information and recipes for purslane, Japanese knotweed, dandelion, kudzu and curly dock.
8. Rubbing alcohol
Rubbing alcohol (isopropyl alcohol) kills weeds by sucking moisture from the leaves. SFGate says to use 2 tablespoons of alcohol to 1 quart of water. Spray it on, taking care to avoid other plants. “If the leaves haven’t withered after a couple hours, spray the plant again,” the article says.
Salt is an effective weed killer that’s a last-ditch solution for limited areas. Rock salt is the most economic form to use. Look for it on sale after winter.
Salt ruins soil for growing anything else. “This is a permanent solution for areas you never want anything else to grow in again,” says another SFGate article. The article tells how to make a salt solution for weed killing, adding:
If you’re interested in improving soil condition, don’t apply any rock salt to the area. Salt serves to weaken the integrity of the soil, and may damage it permanently. The only antidote is to remove the tainted dirt and replace it with new soil, and even that may not restore the area.
Spread a thin layer of salt where you want no plants to grow. Keep in mind that rain will dissolve salt and might leach it into nearby garden beds. Also, make sure when using liquid salt solution that it doesn’t seep or run downhill into beds.
10. Baking soda
Baking soda is another weed killer to treat very carefully. It contains sodium and, like salt (sodium chloride), it makes soil inhospitable to all plants, so use it only where you intend nothing to grow again.
Moisten weeds with water and sprinkle a teaspoon of baking soda onto the foliage. SFGate says, “Test the baking soda method with one or two weeds first to determine if this is the right weed management solution for your landscape, especially if the weeds are growing near desired plants and grass.”