How to Get Rid of Weeds in Cracks Without Using Herbicide
Any landscape with hard surfaces—sidewalks, stone walls, brick borders, paved driveways, etc.—is sure to have at least a few weeds in cracks. Here a some organic solutions to the problem, some more permanent than others.
Pouring boiling water in cracks will kill weeds if their roots are shallow. After treating, simply pull or scrape the scalded plants out by hand. (You may have to apply the hot water more than once. Weeds are real survivors!)
Although boiling water won't actually kill mature weeds like dandelions, which have deep taproots, it will offer a temporary respite from them.
Flame weeders work similarly to boiling water, killing weed growth above ground.
Flame weeders produce the best results (weed death) when used in dry conditions on small weeds. If used on larger, deeply rooted weeds, the results will be temporary, much like treating the weeds with boiling water.
A high-pressure washer, like the ones people use to clean their pavement and siding, is another way to remove shallow weeds effectively from cracks in sidewalks and driveways. Of course, power washing won't work on gravel, and it could blast away the hardscaping as well as the weeds if used on cracks between small stones or border pavers.
MORE PERMANENT WEED SOLUTIONS
Removing weed roots and fleshy roots (like the bulbils on pink oxalis, a.k.a. pink shamrock) is a more permanent solution than killing the weed growth above ground. For prying roots from cracks, weeding knives and hand forks work well.
Pulling weeds with taproots from cracks is often ineffective. More often than not, the root snaps off, only to sprout again. Weeding knives, which often have thin, hooked blades, slip easily into cracks, even narrow ones, making it more likely that you'll remove the whole root.
Although they're not as easy to use against weeds in narrow cracks as weeding knives, hand forks have more uses. For instance, small hand forks are must-haves for removing weeds from beds without disturbing other plants in the garden. They're also handy for prying weeds out of bigger spaces, such as the gaps between edging pavers and stones.
Regularly scrubbing hardscaping with a wire brush is an excellent way to prevent weeds in cracks. It will not only remove weed seedlings, but also weed seeds as well as the dirt and organic matter that would otherwise encourage the seeds to germinate.
A combination of landscaping fabric and gravel works well to suppress weeds between stones and pavers.
PREVENTING WEEDS IN CRACKS
Placing barriers like landscaping fabric under gravel and pavers is a good way to suppress weeds —if the ground is cleared of weeds first. If the barrier is placed over weeds, some of them will simply force their way through the weaving, and they'll be even more difficult to remove.
Mulch & Gravel
A combination of cleared ground, landscaping fabric and mulch or gravel between rocks, stones and pavers is an excellent recipe for weed suppression. Gravel works better than mulch, as mulch will break down more quickly, providing a medium in which weed seeds can germinate and grow.
About the Author
The Dirt Farmer has been an active gardener for over 30 years.
She first began gardening as a child alongside her grandfather on her parents' farm.
Today, The Dirt Farmer gardens at home, volunteers at community gardens and continues to learn about gardening through the MD Master Gardener program.
© 2012 Jill Spencer