If you want a DIY weed killer, consider the following:
Boiling water or laying down newspaper are safe options if you don’t want to alter the soil.
High-acidity vinegar is effective but may reduce the soil’s pH and should be used with care.
Salt works as a weed killer on its own or can be combined with other weed killers to prevent weeds from returning, but it should never be used in areas where you’ll want to grow plants in the future.
Not everyone has the time to spend pulling up weeds by hand, and it can be a struggle to find eco-friendly weed killer in shops. Sometimes, all you need is a good homemade weed killer recipe. Homemade weed killer often doesn’t last as long as tugging weeds up by the roots, but it can be a real time saver if you have a lot of ground to cover.
Laying down newspaper is an effective and environmentally friendly weed killer, but it can be a little ugly. You can cover the newspaper with mulch if you don’t like the look of it, with the bonus effect of blocking the light more effectively.
Homemade weed killer ideas
Boiling water is one of the most eco-friendly weed killer options you have. Boil up some water and, while it’s still hot, pour it (carefully!) directly onto the weeds. It won’t kill the weeds at their roots, but it’s simple, it’s cheap, and it’ll give you some breathing space. It’s also useful for getting into cracks. Salting the water will make it more effective, but don’t use salt on areas where you’re hoping to grow things later.
Salt doesn’t need to be combined with boiling water to work as a weed killer, but as mentioned, it can make it tough or impossible to grow anything at all, so it’s best to keep it out of your flower beds. Sprinkle it over the cracks in your patio to deter weeds (and to deter slugs).
You can lay down newspaper after you’ve cleared an area of any weeds too tall for it to cover. It’ll block sunlight and prevent new weed growth from seeds or roots. Newspaper will disintegrate on its own with time and weather, making it an environmentally friendly weed killer.
Mild household acids such as vinegar or lemon juice will kill weeds. Only spray them on plants you want to get rid of, as vinegar has no way of knowing what’s a weed and what isn’t. You can combine vinegar and lemon juice for a vinegar weed killer recipe that will enhance the effect.
If regular vinegar doesn’t do the trick, horticultural vinegar, which is 20% acetic acid, will usually be more effective. However, be careful when handling high-acidity vinegar. The name ‘vinegar’ may make it sound harmless, but acetic acid can be dangerous in high concentrations. Wear protective gear over your skin and eyes.
For a strong homemade weed killer based on household substances, combine white vinegar in a spray bottle with a tablespoon of salt and a squirt of washing-up liquid. Again, as it contains salt, only use this white vinegar weed killer recipe on areas where you don’t want anything to grow in the future.
Homemade weed killer: tips and warnings
How concerned are you about disinfecting while cleaning?
Whatever your weed killer, use it on a dry, sunny day. It’ll increase the effect and help to avoid the substance being washed away by rain.
Don’t use weed killer in high winds, or it might end up being blown into areas you weren’t planning to use it.
Acidic weed killers, such as vinegar and lemon juice, can increase the acidity of the soil, making it easier to grow certain plants and harder to grow others. It may be safest to avoid these if your plants require alkaline soil.
Never leave dangerous substances, such as high-acidity vinegar, unattended around pets or small children.
Humans are the only weed killer that can tell the difference between weeds and plants you want to keep. If you want to deal with weeds that are surrounded by flowers, it’s best to attack them with your hands or a trowel.
DIY weed killer isn’t the only horticultural helper you can make yourself. Check out our guide to how to make natural pesticides at home.