Gardeners facing a summer weed invasion can turn to a common household item that usually ends up in the bin: cardboard. Plant specialists say this everyday material can act as a natural weed barrier, suppressing unwanted growth while gradually enriching the soil.
How Cardboard Works
According to the team at GardeningExpress.co.uk, cardboard prevents sunlight from reaching weeds, halting their growth. As it slowly decomposes, it turns into organic matter that enriches the garden. The material naturally suppresses unwanted growth while improving soil condition—a win-win for gardeners.
To start, cut a section of cardboard large enough to cover a troublesome patch of weeds, and remove any plastic attached to it. This is vital, as labels or sticky tape are not biodegradable and can contaminate the soil.
Laying the Cardboard
Place the cardboard flat on the ground, pressing it down firmly to ensure full coverage with no gaps. If smaller pieces are available, overlap them by approximately 15 cm to prevent weeds from pushing through edges. This additional layer holds the cardboard in position and retains soil moisture, allowing natural decomposition over time.
Once positioned, the cardboard does the work, suppressing weeds and eventually breaking down completely.
Expert Advice and Additional Uses
Chris Bonnett, horticulturist and founder of GardeningExpress, said: "Weeds can be really frustrating throughout summer, as plenty of sunlight helps them photosynthesise and grow rapidly. They are often an eyesore and, even worse, can take away nutrients from the plants you actually want to grow in the garden. There are many tricks and tips out there to get rid of or prevent weeds, but some can actually cause problems for the rest of your garden, especially when chemicals are involved."
Using spare cardboard is an environmentally friendly approach that recycles old boxes while helping the garden flourish. Material previously destined for disposal gains a new use, freeing up bin space on collection day.
Further uses include laying a sheet at the base of a new raised bed to prevent grass and weeds from pushing through the bottom. Another outdoor tip is sheet mulching, or 'lasagna gardening', which involves overlapping cardboard directly on top of grass or weeds to establish a new bed, then covering it with compost, soil, and wood chips.
