6 Homemade herbicides: Kill the weeds without killing the Earth

Star Wars weed control
CC BY 3.0 Jim Bauer

It's been said that weeds are just plants whose virtues have not yet been discovered, but if you're tired of waiting to find out what those virtues are, you might want to use one of these homemade herbicides instead of the chemical versions.

Many common weeds can be either food, medicine, or unwanted visitors to the garden, depending on the varieties and how you view them. But if you've eaten all of them you can, and you still need to get rid of weeds in your yard, it's far better for you, your soil, and your local waterways to choose a more environmentally friendly herbicide than those commonly found in the home and garden center.

Strong chemical herbicides, pesticides, and fungicides can end up polluting our drinking water, our groundwater, and surface water, so it's important to consider the longer term effects of using them, and to instead make the choice to use a gentler herbicide, which won't contribute to the larger issue of water contamination.

The most environmentally friendly way to get rid of weeds is to pull them up, dig out the roots, let them dry in the sun, and then add them to a compost or mulch pile. However, that method can also take quite a bit of time, so if you're looking for a quicker way to effectively get rid of weeds, one of these homemade herbicides might be the way to go.

[N.B.: Just because these are 'natural' or homemade herbicides, that doesn't imply that they couldn't harm your soil, your garden, or your person. An herbicide is a "substance that is toxic to plants," which means that your garden plants are just as susceptible to these treatments, they could have a negative effect in the soil if applied in large quantities, and they may cause human injuries if misused.]

Drench with boiling dihydrogen monoxide:

This homemade herbicide is by far the simplest to prepare, and unless you happen to spill boiling water on yourself, is also the least harmful to both people and the environment. Simply bring a big pot of dihydrogen monoxide (that's a fancy way of saying water) to boil on your stove, and then pour it over the leaves and stems of the weeds you wish to get rid of. Using boiling water is an effective method for killing weeds in places such as sidewalk or driveway cracks, or over a larger area that you'd like to replant after the weeds are gone, as it doesn't leave any residue or have any harmful long-term effects. As with all of these homemade herbicides, it's still important to only apply it to the plants you wish to get rid of, as they can easily also kill your flowers or vegetable plants.

Light 'em up with fire:

The application of direct heat to the foliage of weeds will cause the plants to immediately wilt, and repeated applications will kill any leaves that may resprout from the roots. A flame-weeder tool is available from home and garden stores, which allows you to apply flame and heat directly to the weeds without catching the whole neighborhood on fire. In fire-prone areas, weeding with flame needs to be done with some extra precautions, as dried weeds and grasses can easily catch fire and get away from you.

Douse with sodium chloride:

Sodium chloride, or common table salt, is an effective herbicide, and has some historical notoriety for possibly being used to lay waste to the soils of conquered peoples (salting the fields prevents plants from growing there). Because salt can have a detrimental effect in the soil, it's important to only apply it directly to the leaves of the weeds, and to not soak the soil, especially in garden beds with other, more desirable, plants. Dissolve 1 part salt in 8 parts hot water (it can be made stronger, up to 1 part salt to 3 parts water), add a small amount of liquid dish soap (to help it adhere to the leaf surfaces), and pour into a spray bottle. To apply, cover or tie back any nearby plants you don't want to kill, then spray the leaves of the weeds with the solution. Be careful to not soak the soil, and keep this mixture away from cement sidewalks or driveways (it may discolor them). Multiple applications may be necessary.

Pickle 'em with vinegar:

OK, so it's not exactly pickling, but by applying this common household item, white vinegar, to weed leaves, they'll die off and make room in your yard for more desirable plants. The white vinegar sold in grocery stores is about 5% acetic acid, which is usually strong enough for most weeds, although a more industrial strength version (up to 20% acetic acid, which can be harmful to skin, eyes, or lungs) is available in many garden supply stores. The vinegar can be applied by spraying full strength onto the leaves of the weeds, being careful to minimize any overspray on garden plants and nearby soil. Repeated applications may be necessary, and the addition of a little liquid dish detergent may improve the effectiveness of this homemade herbicide.

Season them like chips:

Another common homemade herbicide recipe calls for combining table salt or rock salt with white vinegar (1 cup salt to 1 gallon vinegar), and then spraying this mixture on the foliage of weed plants. Adding liquid soap is said to help the efficacy of this weedkiller, as is the addition of certain oils, such as citrus or clove oil.

Harness up the 20 mule team:

Borax, which is sold as a laundry and cleaning product in many grocery stores, might not actually get transported by a 20 mule team anymore, but it could help lend a hand in the yard as an herbicide. Add 10 ounces of powdered borax to 2.5 gallons of water, mix thoroughly, and use a sprayer to coat the leaves of unwanted weeds in your yard. Keep overspray off of any plants you want to keep, avoid saturating the soil with the solution, and avoid contact with bare skin.

If you've been fighting with unwanted weeds in your yard, what other homemade herbicides have you found to be most useful?

Tags: Do It Yourself | Gardening

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