Gardeners can keep weeds at bay all year by repurposing cardboard, a household item that typically ends up in the bin. The method blocks sunlight to stop weed growth and gradually breaks down into organic matter, improving soil health.
How Cardboard Works Against Weeds
The team at GardeningExpress.co.uk explained that cardboard blocks sunlight, preventing weeds from photosynthesising and growing. As it breaks down, it becomes organic matter, giving back to the garden. This natural suppression improves soil health without chemicals.
To start, cut a piece of cardboard big enough to cover the affected area and remove any plastic, stickers, or cellotape, as these are not biodegradable and can pollute the soil.
Laying the Cardboard Correctly
Lay the cardboard flat on the ground, pressing it down firmly with no gaps. If using smaller pieces, overlap them by around 15 cm to stop weeds creeping through edges. This added layer retains moisture in the soil, helping the cardboard break down naturally over time.
Once in place, the cardboard works to suppress weeds and eventually decomposes entirely.
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 leftover cardboard is an eco-friendly method that recycles old boxes while helping the garden thrive. It can also be used at the bottom of a new raised bed to stop grass and weeds pushing up, or for sheet mulching, also known as 'lasagna gardening', which involves overlapping cardboard on grass or weeds, then covering with compost, soil, and wood chips.
