For organic gardening, vinegar can function as a handy natural weed killer. It's the acetic acid in vinegar that gives it the power to kill weeds. The higher the percentage of acetic acid in the vinegar, the better it will operate as a natural weed killer, technically speaking. Vinegar used for culinary purposes is relatively low (5%) in acetic acid, so repeated applications will be necessary when using it as a natural weed killer.
Vinegar As Natural Weed Killer: Limitations
If you're battling lawn weeds, take care to apply the vinegar directly onto the weeds themselves, not letting it come into contact with your grass. Why? Because the fact that vinegar is a natural weed killer doesn't mean it can't be harmful if misused. Vinegar is non-selective, and this natural weed killer can harm your grass!
To avoid damage to grass, consider "painting" the vinegar directly onto weeds with a brush. If you do spray with vinegar, don't pull the trigger until you're right up close to the targeted weed. Don't spray on a windy day, as the wind could carry your vinegar spray where you don't want it to go -- on your grass.
Because of this limitation, I don't think of vinegar as being an especially effective natural weed killer for lawn areas. It makes more sense to use vinegar in areas where lawn grass and other landscaping plants won't be in the way, such as on patios or walkways (where you have weeds pushing up through cracks).
But if you're already in the process of digging a dandelion out of the lawn, it wouldn't hurt to supplement your efforts with vinegar. After you've removed as much of the taproot as possible, carefully pour some vinegar into the hole. The vinegar will seep down into the soil, killing any portions of taproot you may have missed. Afterwards, shovel soil into the hole and sow grass seed on top, lest any opportunistic weed seeds should fill the vacuum.
There's another limitation in using vinegar as a natural weed killer, but this limitation extends to chemical weed killers, as well: namely, that you'll probably have to re-apply the vinegar to get the job done, as weeds often refuse to go quietly. This is especially true of established perennial weeds, toughened by years of coping with environmental challenges; vinegar will be more effective on younger weeds.
But considering that vinegar is safe and relatively inexpensive, this objection is hardly a telling argument against the use of vinegar as a natural weed killer. If your goal is to use a natural weed killer, one assumes that you'll be motivated to make repeated applications, as necessary.
Vinegar As Natural Weed Killer: When to Apply
When practicing natural weed control, take to heart the dictum, Know thine enemy! Study up on the weeds you're battling before you use the vinegar on them. Target annual weeds with your vinegar natural weed killer before they set seed, to prevent them from spawning a new generation to give you headaches next year.
By contrast, early fall is the best time to use this natural weed killer on perennial weeds. Early fall is when you'll want to apply vinegar to dandelions (but snap off the flowers whenever they appear, to prevent them from going to seed in the meantime). Dandelions, although their leaves die back in winter, do live on through their roots. So preventing them from going to seed isn't enough.
Fortunately, knowing a little botany can help you considerably in your battle with perennial weeds like dandelions. You see, in early fall, nutrients are transferred from the dandelion leaves down to the roots. This transfer, which continues until the first killing frost, presents you with an opportunity to hit dandelions where it really hurts! Vinegar natural weed killer applied during this time is absorbed by the leaves and passed on to the roots, following the same path down as the nutrients. The plants are killed -- naturally. Repeated applications may be necessary.
Vinegar As Natural Weed Killer: How to Apply
Listen to your local forecast, and find out when your region will be experiencing a few continuous days of sunshine. At the beginning of this period, spray or paint the vinegar onto the weeds you wish to kill.
Why is a sunny period required? Two reasons:
- You need to saturate the weeds' leaves with the vinegar, and rain would wash too much of the vinegar off the foliage.
- The real damage to the sprayed weeds begins the next couple of days after the application, when the sun hits the leaves.
Some people who use vinegar as a natural weed killer like to boil the vinegar, prior to application. Through such boiling, you may actually be able to gain a concentrate higher in acetic acid, although I haven't yet experimented with this option in any scientific way. But it certainly can't hurt to boil the vinegar; in fact, many folks report success killing weeds by simply pouring scalding water on weeds! So I suppose the use of boiled vinegar allows you to attack weeds on an additional front.
Vinegar As Natural Weed Killer: The Stronger Stuff
It is possible to buy products with a higher acetic acid content than that found in ordinary vinegar. Such products can be purchased at farmer's stores or from restaurant supply businesses. But the potency of these acetic acid products can render them less safe to use than household vinegar. To me, that puts them at odds with the whole concept of using "natural weed killers." Besides, you have to go out of your way to find these products, and the idea behind the present article was to introduce a handy natural weed killer, something you can just pull off a kitchen shelf and experiment with.
Other Uses for Vinegar
Those of you who have held an ongoing grudge against vinegar for its ability to make your mouth pucker may finally be able to grant vinegar forgiveness. For that same sourness makes vinegar the natural weed killer of choice for organic gardening. Vinegar can also be used for cleaning purposes around the home, as an alternative to chemical cleaners.
So if you rarely open that vinegar jug for purposes of seasoning your food, don't despair: The uses for vinegar extend well beyond the culinary.