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How to Get Rid of Onion Grass


About onion grass

The wild onion grasses that grow on your lawns and garden have a very distinctive odor and can be recognized from miles away. The wild onion grass is considered weed and automatically grows in your yard the moment it gets a chance. These onion grasses have flowers and it makes the smell of the lawn have an onion like odor that can be quite strong. It grows from the root bulb during late fall and early spring. It has long waxy leaves and spreads quite easily lasting all winter with the bulbs inside. Even after removal they may sprout back easily in fall gain.

Damage caused by onion grass

The onion grass occupies the space and does not allow other fresh garden grass to grow. Moreover it is toxic for animals. If a child or pet at home may eat it or cattle at farmland and pasture digest the wild onion grass it develops fiber balls in stomach and bowels of the animals that cause a fungus to develop and lead to symptoms like paralysis. It leaves a pungent odor in your garden and does and occupies space for other plants to grow.


  1. Aeration and mulching the soil

Cut off the bulbs and the foliage of the onion grass from your garden with shears or any other sharp cutting device. Mulch the onion grass bed from your lawn 5 to 7 cm deep.  You can carry out this practice on a regular basis until onion grass stops growing. While mulching use spade and trowel to scoop out the clump of grass and mulch and avoid the bulbs.

Aerate the soil clean and dig up to provide air ventilation to the soil, once the grass has been eradicated. Allow air to be circulated through liquid or other substance in the soil. Avoid over seeding your garden this too will prevent your garden from the weeds.

  1. Applying herbicides on the onion grass

Use a spray to apply herbicides to kill the onion grass weeds or use brush to apply on each one of the growth. The chemical can damage soil and other plants. So, it needs to be covered with a black plastic bag after being treated with herbicides to eradicate the grass. Once it covered with a dark plastic bag the chemicals will works it ways into the onion grass. It can be removed from the soil.

GLYPHOSPHATE weed killers such as Round up can be used to kill the onion grass.  Spray chemicals like Image Herbicide - Kills Nutsedge CHLORSULFRON PLUS, PULSE® with 1 gallon water during winter season. Spray Echelon 4SC Herbicide for large fields of onion grass. There are also other great pesticides we carry here at Solutions Pest & Lawn that can successfully treat onion grass like Blindside Herbicide Post Emergent and Martins TopShot Herbicide Weed Killer

  1. Covering the weeds with plastic bags

Herbicides can cause damage to other plants and to the soil as well.mow the grass and slash off and remove foliage before coverage. Cover the areas where the onion grass has covered itself and seal it with dark black plastic bag. Planks or other objects can be used to prevent the bag from flying off or allowing any air into the field of onion grass. When the grass will be deprived of sunlight moisture and it will not be able to photosynthesize and will eventually decay and die. The onion grass can be pulled off after it withers away.

  1. Maintaining soil nutrition

Usually onion grass grows on acidic soil. Check the PH level of the soil and once the weeds have been eradicated dig up the soil during winter season and replace it with more moderate PH Level soil.

Provide the soil proper compost and fertilizers with proper nutrition and make sure the soil is nitrogen free. Such care of the soil will also help in avoiding the onion grass from sprouting during fall again.

  1. Renovating and maintaining the garden

If the onion grass has invaded the whole garden then dig up the whole soil and remove all the bulbs and grass including the whole sod. Change the soil and make sure herbicides are still applied before putting in new soil. Next plant in new fresh seeds and make sure the whole space of your garden has been occupied. Keep your grass trimmed and maintain the soil nutrition. It will help in keep the onion grass from taking up space in your lawn.

  1. Keeping a close eye on your garden

You need to be persistent and vigilant when it comes to onion grass. These weeds are quite stubborn and difficult to get rid of. It is better to keep reapplying the herbicides after few days or week intervals during winter season after all the above mentioned process has been conducted. Keep digging out clumps of grass and mulches, slashing, mowing and spraying chemicals until it is all gone.


With a little bit of hard and patience you will manage to get rid of the onion grass but still do make sure to keep an eye for any onion grass and take care of maintaining the lawn, particularly the soil. Solutions Pest & Lawn is always eager to help you with your lawn care issue. Call us at 800-479-6583, email us at askapro@solutionsstores.com or get online and start a live chat with one of our representatives.

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