Dandelions. Crab grass. White clover. Common ragwort. They’re a nuisance to gardens, stealing nutrients, sunshine, and space from native plants and vegetables. Getting rid of them is no picnic, either—weeding by hand is a battle you’ll never win. When it comes to eradicating weeds from your garden, only a highly effective weed killer will do.

If you stroll down the lawn care aisle of your local big-box store, you’ll find numerous chemicals that will get the job done, but there are plenty of all-natural, DIY options available. They’re often cheaper, too.

My mother-in-law, who has the greenest thumb in Illinois, swears by a homemade herbicide made from the ingredients listed below. While she recommends grinding up your own homegrown chilies, store-bought will work just fine.

Vinegar is the key ingredient here. Because it’s an acetic acid, vinegar kills plants by drawing moisture out of the leaf. This means it won’t kill the roots, which is a good thing—if this weed killer penetrates the soil, it would kill beneficial microorganisms and put the roots of good plants at risk. If your weeds are well established, simply keep an eye on their growth and reapply as necessary.

How to make natural weed killer

1. Mix the ingredients well and allow the mixture to cool to room temperature.
2. Wearing rubber gloves, carefully pour the solution into a spray bottle.

When and how to apply natural weed killer

Target annual weeds before they set seed, usually in the spring or summer. Your homemade weed killer should be applied on a hot, sunny day, when the soil is dry and the temperature is at least 70ºF. This natural weed killer isn’t picky, so be careful where you point your bottle, aiming only at the leaves of the weeds you want to kill.

Storing your natural weed killer

Because you probably won’t use all of the weed killer at once, store any extra solution in a container this highly acidic mixture can’t corrode, such as glass or certain types of plastics, like polyethylene. This will ensure your natural weed killer is ready to go next time you need it.