Pavers are strong, durable and aesthetic stones used for walkways and patios. As with all outdoor surfaces, weeds will try to make their way through them, sometimes sprouting up between cracks in the grout used to hold the pavers in place. If you abandon the pavers to the encroaching weeds, then eventually they will crack and shift, making it difficult to walk on the surface. Before the weeds have a chance to overgrow and cause extensive damage, remove any existing weed flowers and seeds from the ground below and around your pavers.
Eliminate any existing weeds in between your pavers. Cut the weeds down to their crowns and throw away the cuttings.
Boil the kettle and take the boiling water outside while wearing your gardening gloves. Slowly pour the water over the weed crowns, fully saturating each plant. Boiling water will kill the weeds within 24-48 hours, but it will also kill other plants if you are not careful to avoid splashing them.
Fill a spray bottle with 6 tbsp vinegar and 4 cups water. Saturate the weed crowns with the solution. Be careful not to spray or splash any surrounding plants to avoid killing them too.
Remove the dead weeds, including the roots, after 24 to 48 hours by digging out the roots with your hands or a garden hoe.
Prepare your pavers for application of a polymeric sand sealant. This granular material will improve the interlock and stability of pavers, as well as provide an excellent barrier against weed germination. Clean out all of the existing sand in between your pavers using your garden hose or a pressure washer. Allow the pavers to completely dry before applying the polymeric sand sealant.
Sweep the polymeric sand into the joints and cracks between the pavers, making sure to leave no space uncovered where weed seeds could land and germinate. Fill the joints to the top with the sand. Ensure no excess polymeric sand is left on the pavers, as it can be difficult to remove once you get the sand wet.
Begin at the highest point of your pavers and use your garden hose to spray a gentle mist over the area. Avoid dousing the sand as this could wash it away onto another surface. The water mist activates the polymers within the sand and hardens it.
Wait for the sand to set, which usually takes 10 to 15 minutes, then gently mist the area again. The polymeric sand sealant can take up to 24 hours to fully harden, but after 20 minutes it should be suitable to walk on without causing any damage to the surface.
Only apply polymeric sand to your pavers if you are confident that there will be no rain in the next 48 hours. A deluge of rain will wash the sealant all over your pavers and any other nearby surfaces, which will prove very difficult to clean up.