At the height of spring, it's not just lovely cosmos and dahlias bursting into life. This time of year also brings a surge in less welcome growth: weeds.
By definition, those persistent plants have a habit of cropping up exactly where they're not wanted, knuckling their way through cracks between fence panels and tarmac, or – even more frustratingly – paving slabs on paths, patios, or terraces.
Worse still, simply pulling them up rarely rids your outdoor spaces of those pesky plants for good. More often than not, they'll return before too long.
With this in mind, and to help you create an outdoor space you enjoy looking at, we've asked an expert to share the most effective way to clear weeds from your paving – and keep them at bay.
How to remove existing weeds
First, you need to create a clean slate by removing all existing weeds. John Whitney, director of South Wales-based garden buildings and landscaping company Eden Landscapes, recommends a wire brush or a specialist knife for this task.
"A stiff-bristled wire brush or a patio knife dragged along the joints is the most effective manual method and gives you a clean start," he says. "For larger areas, a pressure washer on a rotary head setting blasts out both the weeds and the old jointing material efficiently without damaging the slabs."
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White vinegar or a diluted salt solution can also work wonders, especially on young weeds, although, as John notes, you'll likely have to apply it a few times to be effective, and it won't kill established root systems.
Another household remedy, but one that the expert cautions against, is scalding unwanted plants with boiling water. Although effective in removing them, the heat can compromise the integrity of the pointing mortar between slabs over time.
How to prevent weeds from growing back
The only way to reliably keep weeds from coming back is to seal the cracks. "Once the joints are clear, the best long-term solution is to repoint with a quality polymeric jointing sand or a brush-in mortar compound," John says. "These set firm when wet and create a dense, weed-resistant joint that does not give seeds anywhere to germinate."
This, he says, won't just keep weeds at bay but also give your patio or terrace a more refined finish. You can also consider sealing the entire surface with a patio sealant afterwards to add another layer of protection and make the slabs easier to clean.
Below, read John's step-by-step guide to achieve the best results.
How to apply polymeric joining sand
- Clean the patio thoroughly and make sure the surface is dry: Remove weeds, old jointing material and debris from the joints using a wire brush or patio knife. Polymeric sand should only be applied to a dry surface.
- Pour the sand over the patio and brush it into the joints: Spread it evenly across the surface, then use a stiff brush and sweep back and forth until the gaps are filled to just below the surface of the slabs.
- Remove all excess sand and compact it: Carefully brush or blow residue off the slab surfaces. Any sand left on top can create a haze once wet. Then use a plate compactor or firmly tamp the slabs to help the sand settle into the joints.
- Mist with water and leave to cure: Gently spray the whole area with a hose on a fine mist setting – this activates the binding agent. Keep off the patio for 24 hours and check the weather forecast to ensure no heavy rain during this period.
How to apply patio sealant
- Start with a clean, dry surface: Sweep away dust, loose material and debris and make sure the surface is dry.
- Apply the sealant in small sections: Allow the sand to cure for the full 24 hours before sealing if you've applied polymeric sand. Then, use a roller or wide brush to work the sealant into the surface and avoid puddles in low spots. Also, keep a wet edge to avoid lap marks.
- Apply a second coat if needed: Most sealants require two coats. Apply the second once the first is dry to the touch, usually after two to four hours, depending on the temperature.
- Allow the sealant to cure: Leave the final coat for around 24 hours before using the patio. Avoid rain during the curing period where possible.
Follow these tips to enjoy a weed-free patio or terrace this season and beyond.
Wanda Sachs is the Multiplatform Writer for Country Living and House Beautiful, exploring the latest in gardening, wildlife and sustainable living alongside interiors and property. She is particularly interested in human-interest stories, the intersection of design and pop culture, and the evolving relationship between urban and rural life. Previously, she served as Associate Editor at The Berliner in Berlin, where she reported on culture and fashion. Wanda studied English and German at the Goethe University Frankfurt and Exeter University.
