{"id":5660,"date":"2026-01-13T11:11:10","date_gmt":"2026-01-13T11:11:10","guid":{"rendered":"https:\/\/gardenadvice.co.uk\/gardening-tips\/?p=5660"},"modified":"2026-01-13T11:17:42","modified_gmt":"2026-01-13T11:17:42","slug":"using-cardboard-under-mulch-to-suppress-annual-weeds","status":"publish","type":"post","link":"https:\/\/gardenadvice.co.uk\/gardening-tips\/using-cardboard-under-mulch-to-suppress-annual-weeds\/","title":{"rendered":"Using Cardboard Under Mulch to Suppress Annual Weeds"},"content":{"rendered":"
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Old cardboard delivery boxes <\/p>\n\n\n\n

If you have borders full of annual weeds or large numbers of weed seedlings, using cardboard under a mulch is a simple, low-cost, and very effective solution. This method works particularly well for weeds such as chickweed and is ideal when creating new borders or improving untidy areas.<\/p>\n\n\n\n

This technique is often referred to as sheet mulching<\/strong> and is excellent for reducing maintenance while improving soil health.<\/p>\n\n\n\n

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How Cardboard Mulching Works<\/strong><\/h2>\n\n\n\n

Cardboard acts as a biodegradable weed barrier. By blocking light, it prevents annual weeds from photosynthesising and growing. Over time, the cardboard breaks down naturally, feeding soil organisms and improving soil structure.<\/p>\n\n\n\n

Covering the cardboard with organic matter such as compost, bark, manure, or wood chips improves its appearance, keeps it in place, and further benefits soil health.<\/p>\n\n\n\n

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Cardboard Mulching and Weed Types<\/strong><\/h2>\n\n\n\n

Annual Weeds<\/strong><\/h3>\n\n\n\n

Cardboard mulching is particularly effective against annual weeds<\/strong> such as chickweed and other fast-germinating seedlings. These weeds rely on light to grow, and cardboard prevents them from establishing.<\/p>\n\n\n\n

Perennial Weeds (Important)<\/strong><\/h3>\n\n\n\n

For perennial weeds<\/strong> such as bindweed, couch grass, nettles, or ground elder, cardboard on its own is usually not strong enough. These weeds have extensive root systems and can often push through as the cardboard breaks down.<\/p>\n\n\n\n

In these situations, it is better to use woven landscape sheeting<\/strong>. This should be laid over the soil, cut neatly around existing plants, and then covered with compost, bark, or wood chips. Woven landscape fabric provides long-term weed suppression while still allowing water to penetrate.<\/p>\n\n\n\n

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What Do We Mean by \u201cCompost\u201d?<\/strong><\/h2>\n\n\n\n

In this article, the word compost<\/strong> refers to organic soil-improving materials rather than household compost.<\/p>\n\n\n\n