Does Vinegar Kill Weeds?

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close-up of a liquid being sprayed from a spray bottle outside with grass in the background

Do you wish you had more options for chemical-free weed control? Horticultural vinegar is a worthy addition to your weed-killing tool kit.

If you’ve never thought to use vinegar as a weed killer in your garden, this idea may sound strange. Vinegar (acetic acid) will kill certain weeds, but don’t grab the bottle in the grocery store. Horticultural vinegar is a potent, effective weed killer in certain situations, and it’s worth considering if you want to expand your DIY weed-killing options.

What is horticultural vinegar?

Horticultural vinegar is a strong concentration of acetic acid that is designed to kill weeds around the lawn. The white vinegar you buy at the grocery store (sometimes called pickling or canning vinegar) only contains 5% acetic acid. By contrast, these extra-strength horticultural vinegars start at 20% acetic acid, although higher concentrations are available.

Best uses for horticultural vinegar around the lawn

What you really want to know is: Does it work? Yes, it does work, but as with all weed killers, it kills some weeds better than others. 

Unlike common systemic herbicides, horticultural vinegar is not pulled into the plant’s root system. Horticultural vinegar works by damaging the cell walls of the leaf tissue, which leads to dehydration and wilt, killing the top growth of the plant. This means that it will kill both annuals and perennials, but if the perennial reproduces via an underground structure, it will continue to reproduce.

Before we discuss the best uses, it’s important to know that horticultural vinegar is a dangerous substance. If used improperly, it can cause burns or even blindness. Yes, it is a natural product, but it is an acid and must be treated with caution and care. We’ll get into how-tos and safety practices later on.

Here are a few fast facts about how best to use horticultural vinegar around your lawn.

Horticultural vinegar:

  • Works better on annuals (ex. knotweed) than on perennials (ex. dandelion
  • Works better on broadleaf weeds (ex. chickweed) than on grasses (ex. crabgrass)
  • Most effective on plants that have recently germinated 
  • Larger weeds may require more than one application
  • It will kill perennial leaves, but it won’t kill the taproot, so they’ll continue to reproduce
  • Is non-selective, meaning it will kill the grass as well as the weed, so be careful!

Note: You may have run across homemade weed killer recipes as you surf the internet. The most common one includes store-bought vinegar (5%), Epsom salt or table salt, and dishwashing soap. We’ll let other people comment on the effectiveness of that vinegar solution. In this article, we’ll focus only on using vinegar as a stand-alone product.

How to apply horticultural vinegar

Man using liquid fertilizer in a spray bottle for his garden
CDC | Unsplash

When to apply vinegar to your weeds: The best time to apply vinegar to your weeds is on a hot, dry, sunny day during mid-morning hours after the dew has dried. The sun and heat help the vinegar to work more quickly on the weed. If you apply the vinegar too late in the day, you’ll have less sun, and the morning dew may reduce its effectiveness.

How to use horticultural vinegar:

Step 1: Gear up

Safety is key. This is a natural weed killer, but it is extremely dangerous if used carelessly, so don’t dismiss this step. Always follow the directions on the label for proper safety precautions.

Protective gear:

  • Safety goggles
  • Face shield
  • Long sleeves and pants
  • Rubber shoes
  • Waterproof gloves
  • Respirator

Tools:

  • Sprayer (small, hand-held spray bottle or a pump-action sprayer)

Step 2: Pour the vinegar into the sprayer

If you’re doing a small job, a small spray bottle may be all you need. For a larger area, use a pump sprayer. 

Step 3: Spray the weeds

Spray vinegar on each weed until all plant tissue is wet. If you need to kill weeds in your lawn, another option is to paint the weeds. It’s as simple as it sounds: Use a dedicated brush to paint the leaves of the weed with the vinegar. This method prevents you from killing the surrounding grass. 

Step 4: Evaluate

Depending on the level of concentration and the weather conditions, you may see results in a few hours. Most products say to wait 24 hours to see the full effect. 

Once the weeds have dried up, hand-pull or leave them as you wish. Subsequent applications of vinegar may be needed. Follow the directions on the label for information about followup applications. 

Pro Tip: Wash out the sprayer after each use. This will prevent the vinegar from corroding the sprayer material and seals. Also, release the pressure in the pump sprayer before you open the lid to wash it out. Excess pressure could send vinegar residue flying in the air.

Pros and cons of horticultural vinegar

As we’ve already mentioned, horticultural vinegar is an effective weed killer in some situations, but it is less effective in others. There are also safety considerations to keep in mind. Weigh the pros and cons, and decide what’s best for your lawn.

Pros:

✓ Is nonselective (pro or con)
✓ Works quickly
✓ Works well between rows of crops or garden weeds
✓ Ideal for grass-free areas in the yard: driveways, walkways, areas with gravel or sand, areas with mulch, and flower beds
✓ Chemical-free
✓ Ideal for organic gardening (Look for the “OMRI Certified” label to make sure it isn’t made from GMO corn, for example.)

Cons:

✗ Some are made with GMO (genetically modified) materials
✗ If used incorrectly, can be harmful
✗ If you have kids or pets, you’ll need to put this product in a safe, secure place

If you don’t like having anything around the house that isn’t safe, horticultural vinegar may not be right for you. However, you may still find straight household vinegar effective on just-sprouted weeds in the lawn.

FAQ 

1. Will new weeds grow back?

Perennial weeds will grow back because most perennial weeds reproduce vegetatively (rhizomes, tubers, stolons, and bulbs). The annual weed that you killed, you killed. But more annual weeds will emerge next season. These weed seeds are spread in a variety of ways (wind, animals, foot traffic, etc.), and unfortunately, keeping weeds out of the lawn is a constant battle.

2. Are there other ways to get rid of weeds naturally?

There are several other chemical-free methods: propane weed torches, household steamers, and sunlight and air deprivation (cover with a brick or cardboard). In one USDA study, flame weeding a plot of land resulted in excellent weed control (with repeated applications) throughout one growing season.

3. Will this make my lawn smell like pickles?

The vinegar smell will linger for a few days.

If you’d rather leave your lawn’s weed ID and treatment to the experts, contact one of our local lawn care pros. Let them know you’re interested in chemical-free weed treatment to keep your lawn thriving all year long.

Main Photo Credit: athriftymrs.com | Flickr | CC BY-SA 2.0

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