Safer Ways to Kill Weeds

By Eric Swenson, Executive Director

Weeds are not just unsightly plants – they can cause problems such as allergies and can out-compete native plants that provide food and shelter for wildlife. But commercial weed killers can also cause serious harm to the environment (including Hempstead Harbor) as well as to human health. This article will provide you with some safer alternatives to killing weeds, much of it based on my own personal experience and experimentation.

The safest and most effective way is to simply pull the weed out of the ground by hand, with a hand trowel, or with any number of other tools designed for weeding. One that I have found useful is a “stand up weeder” which is a tool that looks like a pogo stick with only one pedal and a set of claws at the bottom. You place it over the weed, step on the pedal, and pull up the weed, roots and all. You can find these online.

Manual pulling however, is not practical where you have a large amount of weeds. In that case, there are a number of other methods that work, although not as permanently. You have many choices. These include:

• Smothering – cover the weeds with newspapers or black plastic for a week or more until they die. If you use newspapers, you can cover them with mulch and walk away. The newspapers will eventually decompose.

• Burning – there are torches that you can attach to a propane tank that you can then use to burn the weeds. It is like a low end flame thrower. It will burn the plants. I no longer use this method because it does not kill the roots so most weeds come back and it is very heavy to carry around a 15 pound propane tank. I also worry about starting a fire. I see that they now make electric versions of weed torches but have not personally tried these.

• Boiling Water – for areas like cracks in walkways, carefully pouring boiling water will kill the leaves but not the roots. It is a good, safe, inexpensive short-term solution.

• Lemon Juice – like boiling water, spraying lemon juice (such as bottled ReaLemon) will work temporarily. The natural acid, rather than heat, kills the leaves. It may take a day or two for the leaves to die.

• Homemade Weed Killer – my favorite method is to make my own weed killer. The basic recipe is simple: 1 gallon of white vinegar + 1 cup of salt + 1 tablespoon of dish detergent. Don’t worry too much about the quantities – as long as all three are there, it will work. You then use a spray bottle or pump sprayer. I use a 4 gallon backpack rechargeable battery-powered sprayer that works better than any other method I have used. This method works best on a sunny day, as the natural acid will burn the plant and the salt will shrivel it up by sundown (the dish soap helps the solution stick to the weeds). You will be amazed at how well it works. Be careful around your flowers, vegetables, or shrubbery as you don’t want to kill them in the process. Most weeds will eventually return so you will need to repeat this process, but that is the same with commercial weed killers. Note that household vinegar is normally a 5% solution. They do sell industrial strength vinegars for lawns and gardens that are 15%, 20% or higher which will be more effective. They too can be found online. I recently bought some concentrate at 75% which needs to be diluted. You must be careful with these as they can seriously burn you. A 20% mix is the concentration that is mostly used by professional landscapers. Another alternative that would increase the effectiveness is to substitute borax for the salt (again use one cup per gallon). Finally, using a biodegradable dish detergent will be even better for the environment.

Using these methods are one easy way that you can help make the world a better place.