One of the things that most spoils the look of paving slabs is when weeds grow through them. Not only that but this can dislodge the slabs themselves, leading to uneven and wobbly patio areas. But stopping those weeds can be challenging, as any gardener will tell you!
To help out, here are some of the best approaches to stop weeds growing between paving slabs to help you find the right one for your garden.
Removing the weeds
A quick note to say that before you apply any of the processes we’ll chat about here, you need to remove the weeds first. The simplest way to do this is to do it by hand. But remember, the aim is to get rid of those roots where possible.
Manual weed removal
Start with dampening the soil between the slabs with the hose - this will make it easier to pull them out. Grab a weeding tool and some gloves. A billhook or similar style is a great option and there are even weed-removing tools. If all else fails, a simple but sturdy knife will work.
Grab the weed in one hand and the tool in the other. Stick the tool into the root area and move the weed backwards and forwards, pulling gently. This should dislodge the weed with the root intact.
Pressure washer weed removal
Pressure washers can be both friend and enemy to paving slabs. Used correctly, they are a great way to clean them and can also help with weed removal. But if you use too powerful a setting, you can dislodge the slabs and make them unsteady.
Use a strong setting but not the highest one. Don’t linger too long on any spot - if the weed won’t dislodge, go with the manual method afterwards while the ground is still wet.
On paper, weed killers are the easiest way to remove weeds but also come with the most considerations. There are lots of different types but always read up carefully on them, especially if you have pets or children. Also, watch that the weed killer might affect nearby plants if the patio area leads directly to a flower bed or other planted area.
Natural weed killers
The final option for removing weeds is to go with natural products that can kill weeds but are less harmful or tricky to use than chemical weed killers.
Top of the list is vinegar. Because it contains acid, it can kill weeds. Aim for one that has at least 5% acetic acid (usually a cleaning vinegar rather than a table version) then add it with some water and use a spray bottle to apply directly to the weeds.
Baking soda is another natural weed killer. Scatter it over the block paving then use a broom to sweep it into the cracks. Spray with water gently and leave for a while until the weeds die off.
Salt can also be used. Mix 3 parts water with 1 part salt in a spray bottle and spray the weeds. Once it has dried, add more dry salt straight to particularly large or heavy-infested areas.
How to use sand to stop weeds from growing
Once you have cleared the weeds from your patio area, you are ready to start applying your chosen method to stop them from growing back. One of the easiest ways to do this is by adding sand into the joints.
You can add normal builder’s sand to the joints but weeds often find their way through this. The best solution, if you want to use this method, is to use a specialist product that is designed to stop weed growth.
Joint filling sand. One example of this would be the Dansand Joint Filling Sand. This is a mixture of quartz sand with nutrient-poor minerals that makes the joints between your pavings slabs a bit like a desert! This means it is too dry and lacking in nutrients weeds need to grow.
It does remain water-permeable though so there’s no risk of water pooling because it can’t escape through the joints.
Another example is setting sand such as the one from Sika. This is a moisture-cured jointing compound that works in narrow joints such as between paving slabs. It is very quick to use and can be just swept into the joints before being doused with water to set it.
It resists weed growth and is also good for repelling insects that might otherwise burrow through it. The sand will also work for driveways and paths.
Sealing the paving slab joints
The other main way to stop weed growth can be used alongside the addition of specialist sands or on its own. This involves the use of sealants to coat the joints and stop the weeds being able to penetrate it.
Sweep in joint sealants
The best way to use this kind of product is to grab one that is a simple sweep-in method. Examples of these include the Nexus Projoint and Rapidflow Premix. With both of these, you can simply brush the sealant into the gaps in the paving slabs and then use water from the hose to solidify it.
With the Nexus product, you get a totally weatherproof system that isn’t affected by frost. So not only will the weeds be kept away but you don’t need to worry about the frost causing weaknesses in the joints. It is still water-permeable.
The Nexus Rapidflow is ideal to use with natural stone or concrete slabs and has the benefit of coming in five different colours. This means you can pick one that best matches the colour of the paving slabs for a more harmonious look.
Should you seal paving slabs too?
The products mentioned here are for the joints between the paving slabs but you can also get sealants that cover the slabs themselves - but do you need them?
This is definitely a personal choice. You can definitely add a sealant to the top of paving slabs and it can increase their lifespan, helping them avoid cracking due to extremes of temperature. It is a different process to sealing joints but one to consider.
Repel those weeds
Weeds are a big problem with paving slab areas such as patios or pathways. Not only do they look messy but they can cause weaknesses in the foundation of the slabs that can leave them uneven and unstable.
Clearing them and using one or two systems to repel the weeds and prevent regrowth will definitely extend the lifespan of your slabs and keep your patio looking smart for longer.