How to Kill Dandelions Organically
Dandelions (Taraxacum officinale) seem to thrive exactly where you don’t want them to, breaking up the even look of your lawn with their wavy leaves and leggy stems. Because they grow in U.S. Department of Agriculture plant hardiness zones, you’re likely to have problems with them at some point. Killing dandelions don’t have to mean introducing dangerous chemicals into your yard, but you might sacrifice some grass to get rid of the dandelions. Many organic controls kill all plants they touch, not just dandelions.
Dandelions soak up some of the water your grass needs to survive, which is one reason to get rid of them. That same water that gives them life can take it away when the water is hot enough. Pouring boiling water over the dandelion leaves can burn them, causing them to yellow and curl quickly. The hot water soaks into the soil around the dandelion as well, burning the sections of roots that connect with the main plant. With damaged roots and no leaves to soak in the sun’s nutrients, the dandelion will die.
Salt is a highly effective way to kill dandelions and keep them from coming back. When you introduce salt to the area, it leaches into the soil and stays there for years. The downside of using salt is grass won’t grow there for years, either. The best places to use salt are where you want to remove dandelions permanently, such as cracks in your driveway or under a deck. Mixing 1 cup of salt with 1 cup of water is a strong enough solution to kill dandelions. Make that water boiling hot for a more powerful herbicide.
Unlike salt, vinegar won’t leave dangerous residue in the soil to harm future plants. Simply pouring vinegar over the dandelions changes the acidity in the soil for long enough to kill the weeds. For a faster punch, mix pickling vinegar with boiling water in equal parts for your dandelion killer. Pickling vinegar has more acid that distilled white vinegar, so it makes a more effective herbicide.
When to Apply
If you’re pouring plain boiling water over the dandelions, you can apply it any time, even when it’s raining. If you’re using salt or vinegar, with or without boiling water, it’s best to wait until no rain is expected for at least 48 hours so the rain won’t dilute your natural herbicide or cause it to run off toward other plants. With any of the methods, you should start seeing the dandelions wilt in two days or less. If you don’t, reapply your herbicide of choice every two days until the dandelions are dead. If you don’t want to risk killing grass that’s surrounding the dandelions, pull them up by the roots with your hand before they can turn into puffballs of seeds.