If you’ve been gardening for a while, you know that grass can be as invasive in your garden as any other type of weed. It can crowd out plants that you want to grow and compete with them for nutrients.
So, how do you prevent grass from growing in your garden? Lay down a layer of mulch, cardboard, or landscape fabric on any soil where you do not want grass to grow. You can also use raised beds to make it more difficult for grass to invade your garden. To kill grass that is already in your garden, you can spray it with vinegar, pour boiling water over it, or cover it with plastic. Then, you can pull it up easily after it dies.
Of course, there are other ways to prevent grass from growing in your garden. You can plant something else in its place, compact the soil, or lay down patio stones on soil where you don’t want grass to grow.
Let’s start off by looking in more detail at ways you can prevent grass from growing in your garden. Then, we’ll get into ways to kill grass that is already growing.
How To Prevent Grass From Growing In Your Garden
If you don’t have any grass in your garden yet, you are in luck. You won’t need to pull or dig any grass clumps out by hand, and there are several methods you can use to prevent grass from growing in the future.
Cover The Soil With Mulch
Mulching is a great way to prevent unwanted weeds, including grass, from growing in your garden. As an added benefit, mulch also helps to retain soil moisture by preventing evaporation. Mulch also helps to regulate soil temperature by insulating against sudden changes due to heat or intense sunlight.
Mulch is any material that you use to cover the soil in your garden, although most people think of wood chips first. In addition to wood chips, you can use the following as mulch:
- Straw – unlike hay, straw does not have seeds from weeds or other grasses in it.
- Grass clippings – the grass you cut from your lawn is not going to come back to life if you spread it over your soil. However, it can prevent grass from getting a foothold in your garden.
- Chopped leaves – in the fall, you can use your lawn mower to chop up fallen leaves in the yard instead of raking, and then pour the bag onto your garden soil. Alternatively, if you like raking, you can dump your leaf piles right on the soil to prevent grass from growing.
- Manure – make sure it is fully composted before you add it to your garden! Since manure is rich in nutrients and organic material, it may actually harbor the growth of grass as it decomposes.
- Compost – you can use compost as mulch, but as with manure, it is rich in nutrients and organic material, so it may harbor the growth of grass over time. For more information, check out my article on how to make compost.
Remember that mulch will decompose over time. Eventually, you will need to add more mulch to replace what has been lost over time, or else you will start to see grass growing in your garden again.
Cover The Soil With Cardboard
This strategy is similar to the mulching method. Instead of using wood chips or grass clippings, you use cardboard (or perhaps newspaper) to cover your soil. This prevents grass or weed seeds from getting the sunlight they need to get established.
To cover more ground with a cardboard box, be sure to pull off the tape, pull apart the box, and spread it out as much as possible. You can buy boxes at moving companies (Uhaul, etc.) or at storage centers.
However, a better way to get cardboard boxes for free is to go to a wholesale club, such as Costco or BJ’s. Sometimes, they will have carts of cardboard boxes lying around inside the store, waiting to be taken away by customers. Grocery stores or retail outlets may even have cardboard boxes for the taking if you ask.
Usually, you can grab as many boxes as you can carry, since the stores are happy to see them go. In fact, they probably have to pay to have them hauled away if nobody takes them. So, don’t be shy about asking for the boxes the next time you do your shopping!
For more ideas, check out my article on using cardboard boxes in your garden.
Cover The Soil With Landscape Fabric
Using landscape fabric is another method for preventing grass from growing in your garden. This fabric is often black, so that it traps heat and suffocates any grass or weed seeds in the soil.
Landscape fabric can be cut to allow space for plants you want to grow. You can use rocks to weigh down the sides so that the fabric doesn’t blow away in the wind. You can also put down a layer of landscape fabric before mulching to add a double layer of protection against grass and weeds.
Build Raised Beds
Planting part of your garden in a raised bed makes it easier to control what grows and what doesn’t. It is more difficult for grass or weed seeds to be carried into a raised bed by wind, insects, or animals.
Even better, grass growing on the ground around your raised beds cannot “creep up” the wooden sides of a raised bed. You can also plant cover crops in your raised beds to prevent grass and weeds from growing, without worrying about the cover crops taking over your lawn.
Plant Cover Crops
Even if you decide not to use raised beds, you can still use cover crops to prevent grass from growing in your garden.
Cover crops like alfalfa restore nitrogen to the soil, and can also be composted after the growing season is over. Best of all, cover crops prevent grass and other weeds from growing, since it is difficult to get established when cover crops are already growing.
Compact the Soil
You may want to simply prevent grass from growing on garden paths, since it is difficult to mow your garden while your plants are growing.
If you don’t want to grow anything, crops or otherwise, on your garden paths, then one option is to compact the soil. You can use your feet, a flat heavy stone, or a specialized tamping tool to compact the soil into packed earth.
Compacting the soil will help to prevent plants, including grass, from growing in your garden. Just remember that compacted soil does not drain well, which could be a problem if you have clay soil and get lots of rain in the summer.
Lay Down Patio Stones Or Gravel
Patio stones are even better than packed earth. A path of patio stones will prevent grass and other weeds from growing, and it gives the garden a nice look.
They also make it easier to navigate your garden when you need to water, prune, weed, or harvest. If you have trouble with grass between patio stones, try putting down gravel between the stones to prevent growth.
How To Kill Grass That Is Already Growing In Your Garden
Maybe you already have grass growing in your garden, and you want to kill it. Perhaps you are seeing grass in your garden, despite your best efforts to prevent it. Either way, here are some methods you can use to solve the problem quickly.
Spray The Grass With Vinegar
Put some ordinary household white vinegar in a spray bottle, and spray any grass that you want to kill. You might need to use a few applications of vinegar, but the acidity will eventually kill the grass.
The reason is that grass prefers a pH of 6.5 (slightly acidic), whereas vinegar has a pH of 2.4 (very acidic). The sudden shock of a much lower pH is enough to kill the grass in most cases.
However, remember that the same sudden pH shock can also kill your other plants! Be sure to avoid spraying the plants you want to grow in your garden, or your efforts will be wasted.
Remember that some vinegar is watered down to 5% acidity or so, which may not be harsh enough to kill plants. The bottle should indicate this clearly.
After the grass dies, wait a while and it should be much easier to pull it up by the roots. You can also use a shovel or pitchfork to help to pull up clumps of grass that you have killed with vinegar.
Pour Boiling Water On The Grass
Boiling water is not something that plants encounter naturally, and so they don’t really have a defense mechanism for such high temperatures. As with vinegar, you may need a few applications of boiling water, but it will eventually kill the grass.
As before, wait a while and then pull up the dead grass clumps with your hands, or a tool like a trowel, shovel, or pitchfork. You can compost any grass or weeds you kill this way.
Best of all, this method is completely organic, and does not use any chemicals – not even vinegar!
Cover the Grass
One way to deal with unwanted grass is to simply cover it. The lack of air and sunlight, along with high temperatures, will kill the grass quickly.
You can use any of the cover methods mentioned earlier, including:
- Mulch, including straw, grass clippings, chopped leaves, manure, or compost
- Landscape fabric
- Plastic (you will want to remove this from your garden after the grass dies, and then pull up the dead grass to compost it)
Of course, you can also put patio stones right on top of grass, and it will eventually die.
A Word Of Caution About Herbicides
My advice is: don’t use herbicides! Chemicals can be harmful for beneficial bacteria and insects in your garden, such as bees. Herbicides might even harm pets or humans. It is difficult to know the long-term effects of the chemicals used in herbicides, so avoid them if at all possible, and ask your neighbors to do the same.
At this point, you have several methods at your disposal to help you to kill or prevent grass in your garden. All that’s left now is to get out there and do the work!
I hope you found this article helpful. If you have any questions or advice of your own about how to prevent grass from growing in your garden, please leave a comment below.