Say Goodbye To Weeds Growing In Concrete Cracks With One Quick No-Pull Fix

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The broad definition of a weed is any plant growing in a place you don't want it to, and for pretty much any plant, no matter how attractive or useful, the cracks in a concrete driveway or patio qualify as such a place. Weeds grow there because the soil underneath the concrete is moistened by rainwater soaking through the cracks, and because of this, they often have deep roots. In a garden, the best way to get rid of weeds without harming other plants is to pull them out root and all, but roots can be difficult to extricate from small concrete cracks. An easier strategy to effectively kill the weeds is to burn them with a propane torch.

Organic gardeners often use torches, which they call flame weeders, to kill weeds. It's easier than pulling them out one by one, and they avoid using harmful chemicals like bleach as a weed killer, because it's bad for the soil. When you burn the green, photosynthesizing part of a plant, the roots also die, though if they are deep, they may sprout again. When that happens, a repeat flaming usually completes the kill. 

A torch can be deadly to desirable plants when you use one in a garden, so you have to be careful where you point it. No such precaution is necessary on a concrete surface, because any plant growing in the cracks is, by definition, a weed that you want to eradicate.  

An actual flame weeder for use in the garden, like the Flame King Propane Torch Weed Burner, consists of a burner head on a long wand that connects to a propane tank of any size. If you don't have a flame weeder, you may have a soldering torch head that screws onto a handheld gas cylinder, like the Dominox Propane Torch Head. Since you're only spot-burning rather than clearing a large area, this will also work.

 The best time to flame weeds is when they are young and about 1 to 2 inches high, but flaming can also be effective on bigger weeds, depending on the species. You might like the idea of watching the weeds go up in flames, but you don't actually have to burn them to a crisp. Just hold the flame over them briefly until they sag. That wilting is a sign that the plant has died, and it should wither away in a few days. After that happens, watch for new growth, which means the root was deep enough to survive. Repeating the procedure should finish the weed off for good.

A word of caution: If you think any of the plants growing through the concrete cracks are poison oak or poison ivy, do not torch them. Burning them broadcasts their toxins into the air, and inhaling these toxins is dangerous. Plus, having them land on your skin produces incredibly itchy and uncomfortable rashes.