As you can see from this video from the folks at Apartment Therapy , all you need is a piece of carboard—a side of a box will do, as long as it doesn't have ink on it or isn't coated in wax. Just put the cardboard down over the spots of your garden where the weeds are known to live, cover it over with a thick layer of mulch, and leave it alone. The cardboard will keep the weeds from growing up through the dirt and insulate the ground to a temperature that kills the weed seeds. Plus, the cardboard is biodegradable and should break down over the next year under the mulch.
With luck, your garden is growing some lovely goodies right about now, whether you've planted for looks or for food. You may also be growing a few unwelcome weeds here and there as well. Sure, you can pull them up, but they always seem to come back, right? That's because their seeds are below the surface and they grow quickly. The solution? A simple piece of cardboard from an ordinary cardboard box.
Granted, this means that you now have a spot in your garden where you probably shouldn't plant anything new right now, so don't go laying down cardboard everywhere and try to grow something in the mulch on top right away. Try this in areas that you've cleared already, and leave the cardboard alone for a while. Apartment Therapy doesn't mention it specifically, but I've also heard newspaper works well for this purpose. Looking for some more weed-removal tips? We've got you covered . If you have any other garden-friendly weed-killing suggestions, make sure to let us know.
You can further improve the soil’s fertility by layering organic matter, such as compost, leaves, grass clippings or straw, over the cardboard about 6 inches deep, according to the California Native Plant Society. Over time and with the help of microbes and earthworms, the cardboard will begin to break down. If some cardboard is still in place when you’re ready to plant, you can cut a hole through it and place the new plants into the opening. If you’re in a dry climate or your area is experiencing a drought, water the mulched area about once a week.
Cardboard and mulch are effective barriers in stopping the upward growth of unwanted weeds. Over time, cardboard and the dead weeds underneath it biodegrade and help create nutrient-rich soil.
Cardboard and mulch trap moisture in the soil, further enriching it. Earthworms also love it – they thrive in its dark, moist habitat and add a layer of worm castings to the earth, which helps keep the area even more nutrient-rich. Using cardboard and mulch to kill weeds is inexpensive and easy to do. No tilling of the soil is required.
Weeds are a common problem in most yards and gardens. If you don’t want to use harsh chemicals, one easy, practical and safe way to get rid of them is to use cardboard as a weed barrier. Cardboard sheet mulches can stop the upward growth of unwanted weeds. Still, you must carefully maintain a mulch made with cardboard, as it could promote a buildup of chemicals and bacteria and attract other unwanted pests.
Laying Down Cardboard as a Weed Barrier
According to Modern Farmer, using cardboard as a weed barrier will benefit your garden in several ways. When combined with mulch, cardboard is exceptionally useful in keeping unwanted plants from growing or sprouting. Over time, the dead weeds and the cardboard biodegrade and feed the soil underneath with organic matter, boosting its nutrient content.
According to Linda Chalker-Scott, Ph.D., of Washington State University, cardboard sheet mulches can be detrimental to a garden, particularly if they are not appropriately maintained. They can become havens for pests, including termites and voles, who often like to nest underneath them. They can become dislodged by wind or promote the disappearance of oxygen if the soil doesn’t drain well.
When using cardboard to kill weeds and grass in a new planting area, start a few months or an entire season ahead of the time you intend to plant. Heifer International suggests removing any tape or labels from the cardboard packaging before breaking it down flat. Use plain cardboard, as printer ink can be toxic. After placing the cardboard in your garden, anchor it down with rocks or bricks. Then, hose it down with water to promote gas exchange to feed the soil’s microbes.
Why Using Cardboard to Kill Weeds Is Effective
Cardboard that’s too compact can keep water and gases from nourishing soil microbes. If the cardboard sheet mulch dries out too much, it can repel rainfall and prevent moisture from seeping through. Cardboard sheet mulch can serve as an excellent alternative to herbicides in well-watered, well-maintained gardens. However, if yours is not consistently monitored, it can cause more problems with the plants you want to keep in your garden.