Horticultural Vinegar, Does it Work?

Horticultural vinegar has become increasingly popular as people look for alternatives to synthetic herbicides. Marketed as a “natural” weed killer, it promises fast results without the controversy surrounding products like Roundup. But does it actually work?

The short answer: it depends entirely on what you’re trying to kill. Horticultural vinegar excels at burning down foliage quickly, but it has fundamental limitations that make it unsuitable for many common weed problems – and it’s not quite as “natural” as the marketing suggests.

What Is Horticultural Vinegar?

Let’s be clear about what we’re actually dealing with here. Horticultural vinegar isn’t the same as the vinegar in your kitchen cupboard. Regular malt or white vinegar contains about 5% acetic acid – the stuff that gives vinegar its sour taste.

Horticultural vinegar (also called agricultural vinegar) contains 20-40% acetic acid. That’s up to 8 times stronger than cooking vinegar. At these concentrations, it’s not something you’d want anywhere near your chips – it’s a corrosive acid that will burn skin on contact and can cause serious eye damage.

Despite the “vinegar” name, this is essentially industrial-grade acetic acid. Most commercial products are synthetically manufactured rather than brewed like real vinegar. The “natural” marketing is somewhat misleading – while acetic acid does occur in nature, concentrated formulations like this are manufactured chemicals.

How Does It Kill Weeds?

Horticultural vinegar is a contact herbicide. When sprayed onto leaves and stems, the concentrated acid burns and desiccates plant tissue, causing rapid cell death. The foliage essentially gets acid-burned and dries out.

This is fundamentally different from systemic herbicides like glyphosate. Systemic products are absorbed by the plant and transported throughout its entire system, including down into the roots. Horticultural vinegar stays exactly where you spray it – it doesn’t move through the plant at all.

The speed is genuinely impressive. You’ll typically see visible browning and wilting within 24-48 hours, with complete foliage death in 2-7 days depending on conditions. This rapid knockdown is why people find vinegar appealing – you can see results quickly.

The Big Problem: Roots Survive

Here’s the critical issue that vinegar advocates often gloss over: because it’s a contact herbicide, any weed with an established root system will simply regrow.

The foliage dies back impressively fast, giving the appearance of success. But 2-3 weeks later, fresh green shoots emerge from the intact root system. The roots weren’t touched by the acid, so they still have all their energy reserves to produce new growth.

This means horticultural vinegar is essentially useless against perennial weeds like dandelions, dock, bindweed, and couch grass. You might burn off the visible growth, but the underground root networks remain entirely unharmed.

For tough woody weeds like brambles, horsetail, or ivy, vinegar is completely ineffective as a long-term solution. Council weed control trials have consistently shown that vinegar requires significantly more applications than glyphosate to achieve comparable results – and even then struggles with established perennials.

Horticultural Vinegar vs Glyphosate

The comparison matters because vinegar is often marketed as a “safer alternative” to glyphosate. Let’s look at the facts:

Effectiveness: Glyphosate is systemic – it’s absorbed and transported throughout the entire plant, killing roots and all. Vinegar only kills what it touches. For perennial weeds, glyphosate wins decisively.

Cost: A 5L bottle of horticultural vinegar costs £25-30 and is typically used undiluted or at 1:1 dilution (giving you 10L). A 1L bottle of glyphosate concentrate at similar price makes 50+ litres. Vinegar is roughly 5x more expensive per treated area – and you need more repeat applications.

Soil Impact: Here’s something that might surprise you. Glyphosate binds tightly to soil particles and doesn’t affect soil pH or microbiology. Concentrated acetic acid can significantly alter soil pH, harm beneficial soil organisms, and damage nearby plants through pH changes. Research suggests glyphosate may actually be gentler on soil health than concentrated vinegar.

Safety: Neither is safe to drink, but concentrated acetic acid is immediately corrosive – it burns skin on contact and can cause permanent eye damage. Studies on rats found that acetic acid was more acutely toxic than glyphosate at comparable doses.

Speed: Vinegar works faster – visible results in days versus 1-2 weeks for glyphosate. But speed without root-kill means the job isn’t actually done.

For a broader comparison of herbicide types and when to use each, see our complete guide to weed killers.

When Horticultural Vinegar Makes Sense

Despite its limitations, horticultural vinegar does have legitimate uses:

Annual Weed Seedlings: Young annual weeds with shallow, undeveloped root systems can be killed outright. Chickweed, groundsel, and annual meadow grass seedlings are good targets when caught early.

Paths and Patios: For weeds growing in paving cracks where you’re prepared to respray every few weeks, vinegar can maintain weed-free surfaces. It’s a maintenance approach rather than a permanent solution.

Organic Requirements: If you’re growing organic produce and need to use approved organic inputs, concentrated acetic acid may be permitted where synthetic herbicides aren’t. Check certification requirements.

Glyphosate Resistance: Some weed populations have developed resistance to glyphosate through overuse. Vinegar offers an alternative mode of action for resistant weeds – though you’ll still need multiple applications.

Quick Cosmetic Results: If you need weeds to look dead quickly before an event or property viewing, vinegar delivers fast visual results. Just understand they’ll likely regrow.

What About Regular Kitchen Vinegar?

Standard household vinegar (5% acetic acid) is essentially useless as a weed killer. It might slightly damage very young seedlings on a hot day, but established weeds will shrug it off completely. The “vinegar weed killer” recipes you see online using kitchen vinegar, salt, and dish soap are largely ineffective and the salt can permanently damage your soil.

If you want vinegar to work at all, you need the horticultural-grade 20%+ concentrations – and even then, it only works on foliage.

For more on homemade weed killer effectiveness, we’ve tested the common recipes.

Can I Use It On My Lawn?

No. Horticultural vinegar is non-selective – it will kill lawn grass just as readily as weeds. Spray even a little on your grass and it will die, leaving bare patches that won’t grow back on their own.

Additionally, the pH changes from concentrated acid can harm lawn health long-term, creating conditions that favour moss and disease.

For lawn weed control, you need selective herbicides like 2,4-D or dicamba that target broadleaf weeds while leaving grass unharmed. These are specifically designed for lawn use.

Safety Considerations

Don’t let the “natural” marketing fool you into thinking horticultural vinegar is harmless. At 20-40% concentration, it’s a corrosive acid that requires proper precautions:

Eye Protection: Essential. Concentrated acetic acid can cause permanent eye damage. Wear proper safety goggles, not just glasses.

Skin Protection: Wear gloves and long sleeves. Contact causes acid burns that need immediate rinsing with water.

Respiratory: The fumes are irritating. Work in well-ventilated areas and avoid breathing the spray mist.

Pets and Children: Keep them away from treated areas until completely dry. While dried residue is less dangerous than wet spray, it’s still acidic.

Nearby Plants: Any drift will damage plants you want to keep. The pH changes can also affect nearby plants through soil contact.

How Long Does It Stay in Soil?

Unlike some persistent herbicides, acetic acid doesn’t bind to soil and washes away with rain. It has no residual weed prevention – once it’s gone, new weeds can germinate immediately.

However, repeated applications can significantly alter soil pH, making the soil more acidic. This can affect what plants will grow well and may create conditions favouring moss and certain weeds over desirable plants. Here in the UK where rain is frequent, the pH impact is usually temporary, but prolonged dry spells can extend it.

Frequently Asked Questions

Will horticultural vinegar kill weeds permanently?

Only shallow-rooted annual weeds and young seedlings. Any weed with an established root system will regrow within 2-4 weeks because vinegar doesn’t reach or damage roots. You’ll need repeated applications for ongoing control.

Is horticultural vinegar safer than Roundup?

Not necessarily. Concentrated acetic acid (20-40%) is immediately corrosive – it burns skin on contact and can cause permanent eye damage. Studies suggest it may be more acutely toxic than glyphosate. It also affects soil pH where glyphosate doesn’t. “Natural” doesn’t automatically mean “safer”.

How long does vinegar take to kill weeds?

You’ll see visible browning and wilting within 24-48 hours. Complete foliage death typically takes 2-7 days depending on weed size and weather conditions. Warm, dry weather speeds the process.

Why do weeds grow back after using vinegar?

Because vinegar is a contact herbicide that only kills the plant parts it touches. The root system remains completely intact underground. As long as roots survive, the plant has energy reserves to produce new growth.

Can I use regular kitchen vinegar as weed killer?

It’s essentially ineffective. Standard vinegar (5% acetic acid) is too weak to kill anything but the smallest seedlings. You need horticultural-grade 20%+ concentrations for any meaningful effect – and even then, roots survive.

Is vinegar better than pelargonic acid?

They work similarly – both are contact herbicides that burn foliage without killing roots. Pelargonic acid tends to work slightly faster (hours vs days) but both require repeated applications for perennial weeds. Neither matches systemic herbicides for permanent control.