Fill the joints between the block paving with polymeric sand, a special sand product that turns into a solid that still allows flexibility once it is misted with water. The solid joints won’t allow weeds to grow up in the cracks.
Pull any weeds that grow up through the block paving by hand. A putty knife or special weeding knife helps reach weeds that are in the cracks. Remove as much of the weed and root system as possible and dispose of them so they don’t take root again.
Block paving offers an affordable way to create pathways or patios in your landscaping, but the individual blocks provide an opportunity for weeds to squeeze in through the cracks. Not only do the weeds look unattractive, they could cause shifting or damage to the pavers. Stopping weeds in paver areas starts with the installation of the walkway or patio. Continued maintenance to control weeds as soon as they appear prevents the unwanted greenery from taking over your block pavers.
Use drip irrigation or a soaker hose to water nearby plants. This keeps the water near the plants you want to keep and away from potential weeds in the block paving. Without adequate water, the weeds are less likely to grow.
Spray a chemical herbicide on persistent weeds that regrow. Direct the chemicals to the weeds on a calm day so the herbicide doesn’t blow to other nearby plants. Organic herbicides offer an option with fewer harsh chemicals for less potential environmental impact.
Once it is dry – it can take up to three hours – apply a second coat. Refer to the manufacturer’s instructions for precisely how much sealant is required per application and whether you need to apply a second coat. The more coats you apply, the glossier a finish you will end up with.
If you buy and use a cheaper product you may find yourself having to seal again in a year or two.
In terms of cost, you really do get what you pay for. Generally speaking, the more expensive the sealant, the better it will be.
Instead, sealing block paving is a highly-recommended method of sealing, stabilising and protecting the block paving effectively. It is also one of the most successful steps you can take to stop weeds from establishing, growing and returning.
Preparing the Area
Remember, there is no such thing as a surface that is weed-free , and spraying the area with weed killer – no matter how powerful – is simply not enough.
Before starting, ensure the block paving is dry and clean. If possible, leave it a few days between cleaning and sealing. This will enable you to check that the cleaning has not produced any efflorescence (crystalline deposits) on the blocks.
After preparing the surface in question, apply one coat, making sure the whole area is saturated – but avoid creating puddles. Start by pouring the sealant out, then use a pile roller or squeegee to roll it out- unless you have a sealant that can be sprayed.
Choosing the Right Sealant
While effective sealing is the best way to stop weeds growing through block paving, don’t assume the job is completed once the block paving is sealed. Ongoing maintenance is necessary to keep your paving in fine form throughout the seasons.
It is crucial to carry out the sealing when the weather is dry to minimise the chance of any moisture build-up within the blocks, as well as surface moisture on top from rain. Aim for some time between May and September to be on the safe side.
Summary: Effective and environmentally friendly but time consuming.
Is using salt solutions to kill weeds in block paving just an old wives tale or can it be effective?
Summary: Very cheap but can easily contaminate surrounding areas. Needs regular re-application.
Spraying weed killer
Contact weed killer will work if you have a flourishing array of weeds in your block paving. Glyphosate is a common example of contact weed killer. It works when absorbed through the leaves of a plant but is ineffective in the soil and wont enter plants through the roots.
Weed burners are unlikely to stop the weeds completely but they are an extremely clean way of dealing with weeds. Both gas and electric versions are available. Gas will be faster and more effective.
Weed killer can take some time and up to 3 applications to completely kill off weeds. This can take up to a month depending on how stubborn your weeds are. The name of the game is persistence and patience.
How should salt be used?
The most common type of weed killer, systemic weed killer works its way through plants to kill each part including the roots.
Best for: Preventing growth of new weeds