Few things give a landscape a more untended look than masses of weeds. One way to deal with pesky weeds is to kill them with store-bought, chemical herbicides. But this approach doesn't cut it with gardeners striving for landscapes that are not only weed-free, but also safe for people, pets, and wildlife. For them, mere weed control isn't as important as achieving weed control without chemicals. In fact, such gardeners sometimes choose to tolerate weeds such as wild violets, rather than fighting them.
However, if you're the type of gardener who's "green" but who loves well-manicured landscapes and perfect lawns, too, you must look for smart ways to control weeds. Luckily, there are some homemade weed killers you can use. They are safe and they really do work. Moreover, you can supplement them with other strategies that are effective against weeds yet won't harm the environment.
Homemade weed killers are generally non-selective solutions—they kill whatever plants they touch. For this reason, be careful in how you apply them. For example, sprayed on lawn weekd, these weedkillers will also kill any grass plants they happen to touch. These weed killers are easier to use on garden areas, where you can apply them more selectively.
Vinegar spray is one of the best homemade weed killers. It's easy to prepare and effective against a variety of weeds. All you need for ingredients are:
- A vinegar that is high in acetic acid
- A surfactant (this substance doesn't kill weeds; its role is to help the vinegar herbicide clng to and penetrate into the weeds' leaves). Ordinary dish soap can work quite well as a surfactant.
Pour the ingredients into a spray bottle and shake to mix. Apply when the weather report says you'll be getting a few continuous days of sunshine. Rain will wash the vinegar off the weeds too soon and most of the damage happens when the sun hits the weeds' leaves.
Spray directly onto the weeds, being careful to keep it away from other plants.
Rubbing Alcohol Solution
This astringent substance works by removing moisture from the weed's foliage. Deprived of its life force, the weed dies. Mix the solution in a spray bottle for ease of use.
Preparation is as simple as diluting the rubbing alcohol with water: use a quart of water to dilute every two tablespoons of rubbing alcohol. As with vinegar, apply on a sunny day, and spray directly onto the weeds, being careful to keep it away from other plants.
This homemade weed killer is the easiest of all to prepare and use. You won't be doing any mixing at all, and you can apply it at absolutely any time you wish: day or night, with or without sunshine, even in the pouring rain.
Simply boil some water and pour it on the leaves of the targeted weed. Pour enough so that it seeps down into the roots, too. It's helpful to have a kettle to boil the water, so that when you pour the stream of boiling water can be carefully directed with a spout. Scalding a desirable plant with boiling water may kill it.
Similar to the way that boiling water kills weeds, roots and all, the same effect can be enjoyed by using a propane torch to scorch the center of the weed. There are a variety of long-handled torches made specifically for this purpose. The tool consists of a long tube with a flame tip, and an attachment fitting where you can connect an ordinary bottle of propane fuel. The long handle means you can kill weeds without stooping. Naturally, you should use extreme caution when using this tool in dry conditions or in brushy areas.
Corn gluten falls into a different category. It's a weed suppressor rather than a weed killer, making it impossible for weeds to appear in the first place. Corn gluten is most commonly used to control crabgrass (Digitaria).
Corn gluten, if used properly, inhibits the formation of those first roots crabgrass seeds put out after they germinate. But proper use requires two things:
- Application must be timed so as to coincide with crabgrass germination, which happens at roughly the same time that lilacs (Syringa vulgaris) in your region are blooming.
- Application must also be timed so as to occur during a dry period.
Corn gluten is organic, being a powder that's left over after corn is milled. There's no mixing: You simply spread the powder over the soil. Water the corn gluten into the soil after application (about 1/4 inch of water is required). But after you water it in, the weather must be dry for a couple of days. Otherwise, the roots won't be killed.
The drawback in using corn gluten is that there's an element of luck involved. If it rains during the whole week when crabgrass is germinating in your area, you're out of luck.
As with homemade weed killers proper, corn gluten is non-selective: It suppresses all types of germinating plants, not just weeds. So it's not something you'd want to put down on your grass at a time when you're overseeding your lawn.
Other Smart Ways to Suppress Weeds
While vinegar, rubbing alcohol, and boiling water really do work to kill annual weeds, they won't work against some of the tougher, perennial weeds. For such weeds, you'll have to take different measures. You can still stay organic, but it takes some extra creativity and work on your part.
For example, if you're persistent, you can control Japanese knotweed (Polygonum cuspidatum) without resorting to the use of glyphosate herbicide, which is the normal recommendation. Cut the knotweed down, clear dead canes away, and place tarps over the ground. Deprived of sunlight, the weed's food reserves will eventually be exhausted. But not before it sends out shoots beyond the tarps' perimeter in search of the needed sunlight (you'll be removing these shoots for years before exhaustion finally sets in).
Similarly, covering ground in the garden with any of the following helps to suppress weeds:
Even something as simple as crowding out weeds is an effective tactic. That's why some people don't need mulch for their cottage gardens: The plants are packed so closely together that there's no room for weeds. Likewise, a healthy lawn will grow so thickly that weeds won't have any openings to exploit.