Quack grass conumdrum

Asked July 11, 2019, 11:36 AM EDT

I have read that one can spray quack grass with straight vinegar to get rid of it out of lawns. My problem is that this plant is all over the rather substantial vegetable plot. I have been pulling it out for the last couple of years, but it seems to always be back the next one. Would the vinegar harm the vegetable plants? Would the vinegar harm the soil? Thank you for your kind attention and answer to my question.

Outside United States weed issues quackgrass

1 Response

Hello,

Vinegar burns the tops of plants. It doesn’t kill roots, unless the root itself were sprayed. It will burn vegetable plants.

Here is a discussion on vinegar used as a herbicide:

http://hyg.ipm.illinois.edu/pastpest/200714f.html

Since vinegar is a contact herbicide, if applied to soil it will have no affect on weeds that germinate afterwards.

Vinegar at high enough percentages to kill vegetation is dangerous to people and pets, too. Please note the precautions mentioned in the article above.

Here are the recommended quackgrass controls from Extension:

Handpulling and hoeing are useful for controlling quackgrass in gardens. Cultivating also forces quackgrass to use its food reserves to produce new growth. But unless done frequently or in combination with herbicide treatments, cultivation does not adequately control quackgrass and can even spread rhizomes, making the problem worse. Cultivation is most effective during periods with hot, dry days and warm nights, when the rhizomes are most likely to dry out.

Glyphosate provides good control in the fall after crops are harvested, or in spring prior to planting. For best results, quackgrass should be 8 to 12 inches tall and actively growing. Fall treatments applied after a light frost can be successful, as long as quackgrass is still green and temperatures are relatively warm at application time.

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