Does vinegar work better than Roundup?

By The Weed Guy·Last updated 2 September 2026

On a young annual weed, yes, and it will look better doing it. On anything with an established root, no, and it is not close. Vinegar is a contact treatment: acetic acid destroys the plant tissue it physically wets and travels nowhere afterwards. Glyphosate is systemic, so the plant draws it in through the leaf and carries it down into the root itself. Which one is better has almost nothing to do with strength, then, and everything to do with whether the weed in front of you is an annual or a perennial.

The study everybody quotes actually settles it, if you read the whole sentence. USDA Agricultural Research Service scientists at Beltsville, Jay Radhakrishnan, John Teasdale and Ben Coffman, tested vinegar on five weed species and published in 2002. The 5 and 10 percent concentrations killed the weeds during their first two weeks of life. At 15 and 20 percent, vinegar reached an 85 to 100 percent kill rate at all growth stages. Then the line that gets quoted hardest of all: Canada thistle, one of the most tenacious weeds in the world, proved the most susceptible, and the 5 percent concentration had a 100 percent kill rate of the perennial's top growth.

Top growth. The whole answer is sitting inside the most pro-vinegar statistic in existence, and it gets dropped every time the figure is repeated. Canada thistle is a creeping-rooted perennial that regenerates from buds on its roots, so a 100 percent kill of everything above the soil is precisely the result that does not finish it. Kitchen-strength vinegar had a spectacular week, and the plant still owned the ground.

That trade is the real answer to the question, and it explains why vinegar wins every head-to-head anyone bothers to film. It works in hours. Spray on a warm morning and by teatime the weed is brown and crisp, which reads as proof. Glyphosate spends that same week doing something you cannot see. The professional Roundup ProActive label (MAPP 21225, 360 g/L glyphosate) says symptoms of treatment are generally first seen 7 to 14 days, or longer if growth is slow, and asks you to allow 2 to 3 weeks before re-treating anything unaffected. Judge the pair on day three and vinegar wins on looks while losing on the only measure that counts.

There is also a question hiding inside the question: which Roundup. The name covers several different chemistries in this country rather than one product. There is a ready-to-use glyphosate at 7.2 g/L, a professional glyphosate concentrate at 360 g/L, a pelargonic acid product with no glyphosate in it at all, and Roundup Speed Ultra, MAPP 18692, which is 60 g/L acetic acid. That last one is vinegar. Sixty grams per litre works out at about 6 percent acetic acid, against roughly 5 percent in the bottle in your kitchen cupboard. So a fair few people running this comparison are comparing vinegar with vinegar and wondering why both sides brown off and both sides grow back. Read the active ingredient on the back of the bottle before you compare anything.

One date is worth knowing before you commit to the acid route. HSE amendment notice 20250596, issued on 1 April 2025 as a result of Commission Implementing Regulation 2023/1446, ends the authorisation of around thirty amateur acetic acid weedkillers on 30 November 2027, allows sale and distribution of existing stocks until 31 May 2028, and use and disposal of existing stocks until 31 May 2029. Roundup Speed Ultra is on that list. Worth keeping the two things apart as well: an authorised acetic acid weedkiller with a MAPP number on the back is a regulated product, and the vinegar in your kitchen is not that product. HSE's line on using common household chemicals as a plant protection product is that it is not without risk and is not always legal, and where household vinegar sits on that is something I have not been able to establish, so I am not going to claim it either way.

None of which makes vinegar useless, and the honest split is more use to you than a lecture. Where it genuinely wins is the small, the young and the shallow: seedlings in the joints of a patio, soft new growth in gravel, anything you could still lever out whole with a screwdriver. It is fast, it leaves nothing residual in the ground, and for spot work beside something you want to keep, both of those are real advantages. Where it never wins is anything that lives downstairs. The RHS is flat about it on its own ground elder page, saying vinegar is not an effective control method, and the same goes for bindweed, couch grass, dandelion taproots and every other perennial rooted in a joint.

So, plainly. If the weed is an annual or a seedling, vinegar is the better tool, because at that size the leaf more or less is the plant and speed is worth having. If it is a perennial, glyphosate is not merely better, it is the only one of the two capable of the job at all, and stepping up to 20 percent horticultural vinegar does not change that. It changes how fast the top burns off, and how badly it burns you if you get it on your skin. Strength was never the variable. Reach was.