Weeds and grass growing in the joints between pavers are a common maintenance problem. These narrow gaps naturally collect moisture, dust, and organic matter, creating a fertile environment where seeds easily germinate. Preventing this unwanted growth requires a multi-step approach, moving beyond simple weeding to structural solutions and ongoing suppression. This strategy details how to clean, seal, and maintain paved surfaces, effectively blocking the environment that allows grass and weeds to thrive.
Clearing Existing Growth and Preparing the Joints
Achieving a long-term solution requires completely removing all existing organic material from the paver joints. Remaining roots or debris will compromise the effectiveness of subsequent sealing treatments.
Physical removal is best accomplished using specialized joint scrapers or wire brushes that reach deep into the narrow crevices. Manually pulling weeds ensures maximum removal of the root system, which prevents immediate regrowth. Clear the joints of all soil, sand, and plant life down to a uniform depth, typically about one inch or until the base layer is exposed.
Once the bulk of the material is removed, a pressure washer can clear out stubborn dirt, fine debris, and shallow roots. Use a fan-tip nozzle at a safe distance to avoid damaging the pavers or the underlying base material. The paved area must then be allowed to dry completely, which may take 24 to 48 hours depending on humidity and sun exposure, ensuring optimal conditions for the next step.
Implementing Long-Term Structural Barriers
The most effective strategy for preventing future growth is installing a structural barrier that physically blocks the space between the pavers. Polymeric sand is the primary material used, offering a durable, semi-rigid joint filler. This material is a specialized blend of fine sand and polymer additives that cure when activated by water, forming a hardened, yet flexible, barrier.
The application requires sweeping the dry polymeric sand into the cleaned joints until they are filled. Follow this with light compaction to settle the material deep into the gaps. A fine mist of water is then applied to the surface, activating the polymers within the sand. As the polymers cure, they bind the sand particles together, creating a tough barrier that resists the erosion caused by rain and inhibits seed germination.
This hardened material is difficult for wind-blown seeds to penetrate and does not provide a loose medium for roots to establish. For maximum effectiveness, the sand should be applied to the correct depth, ensuring it sits just below the paver edge to prevent pooling water. Alternative hardscape sealants are also available, designed to penetrate and harden existing joint material, further stabilizing the filler and protecting the surface.
Ongoing Suppression and Maintenance Treatments
Even with a hardened joint barrier, airborne seeds and organic matter can settle and attempt to germinate. Routine maintenance and topical treatments are necessary to suppress any new growth.
Non-Chemical Suppression
A common non-chemical approach involves applying concentrated vinegar solutions, which act as a natural desiccant. Household vinegar is about five percent acetic acid, but stronger horticultural vinegars (20 to 30 percent acidity) are more effective for killing established weeds. These solutions are non-selective, so precise application is necessary to avoid damaging nearby landscaping.
Chemical Treatments
Commercial herbicides offer another layer of defense. Pre-emergent herbicides are proactive treatments that create a chemical barrier in the top layer of the joint filler, preventing seeds from germinating. They must be applied before the weed seeds sprout, typically in early spring and fall.
Post-emergent herbicides are designed to kill weeds that are already actively growing. These are used as spot treatments on any new sprouts. Regular sweeping to remove organic debris, such as leaves or dirt, also significantly reduces the available medium for seeds to root, supplementing the structural barrier.