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 are some organic solutions to the problem. Some are more permanent than others.
Temporary Solutions to Weeds in Cracks
Here are a few options for killing weeds that should do the trick when weeds are a temporary problem.
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 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 hardscaping as well as weeds if used on cracks between small stones or border pavers.
More Permanent Solutions for Killing Weeds
Removing weed roots and fleshy roots (like the bulbils on pink oxalis, a.k.a. pink shamrock) is a more permanent solution than killing 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 narrow cracks, 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 seeds to germinate.
Preventing Weeds in Cracks
Here are a few techniques that will hopefully prevent most weeds from coming back through the cracks.
Placing barriers like landscaping fabric under gravel and pavers is a good way to suppress weeds—but only 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 and 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.
© 2012 Jill Spencer