One of the most frustrating things after you've laid patio stones and pavers is when tiny weeds start to pop up in between the cracks. After all the hard work and money that goes into a big project like that, you want to rest assured it's going to look great for years to come.
The best way to prevent weed growth between pavers is to install them properly in the first place. This article will go over the steps to take on prepping the site, and other prevention tips, as well as how to get rid of existing weeds so they don't come back.
How Do Weeds Get In?
Unfortunately, weeds are a part of nature, and by their very definition, they stubbornly find places to grow where little else can thrive. They love to find their way into cracks and crevices along driveways and between pavers, and while their tenacity is admirable, they're literally a pain in the neck to remove.
One of the main ways that weeds and grass pop up between pavers is simply from growing underneath them. This will happen if you don't properly prepare the site before laying your pavers down.
Even though the majority of the area is covered, even just a small crack can allow stubborn weed species like crabgrass, purslane, or dandelions to take root.
Although certain weed species, (especially the last two) are becoming more tolerated for their culinary and herbal uses, most people don't want them growing in and around their patios. A thick enough barrier using the right materials can stop or prevent anything from growing for years, or even decades if done properly.
The other way that weeds start to form between pavers is from seeds being blown into the crevices by wind, or washed over them when it rains. This natural process is hard to prevent, as mother nature stops for no one.
There are a few ways to prevent this type of growth after pavers have been installed, however, and most of it is through maintenance and sealing your pavers properly after they've been installed.
Just remember that while prevention is key, you will eventually have to deal with weed growth along the way.
Prep the Site
While laying pavers is a labor-intensive job, the most important work comes before you start installation. Just like most projects, making sure you start this job off right will pay off in the end.
If there's any existing lawn, plants, or weeds growing in the area, remove enough of the dirt to get at the roots so no plant life is left. It's okay if you have to dig down to get everything out, as you're going to be building the area back up with other materials to create a base so that everything is level.
Another way to quickly kill grass if you plan ahead is to lay cardboard, tarps, or dark plastic sheets on top of the area. After a month of two without sun or air, anything underneath will be dead.
Make a Proper Base
A properly dug-out and prepared base is essential for keeping weeds out and installing pavers successfully. One of the biggest mistakes is not digging deep enough before laying stones.
Ideally you want at least four inches of gravel, as well as one or two inches of limestone screening underneath your pavers for typical paver installation projects. You'll end up removing about half a foot of soil, taking into consideration the thickness of the pavers themselves.
The gravel allows for a sturdy base, as well as proper water drainage when it rains and snows. Limestone screening is a thinner, sandy material that works perfectly as an underlayment for stones and pavers.
Limestone screening is easy to work with and level out smoothly. It's also weather-resistant and allows for good drainage, but also deters weed growth and insects from forming because of its alkaline properties.
Lay the Pavers Properly
Once your base has been prepared and leveled, you can start laying the pavers using the "click and drop" method. Place a paver against the other one so that it's flush, and when it "clicks", drop it in place. This prevents the sand from being disturbed.
Pay close attention to the spacing while you are installing them. Certain types of pavers can be laid directly next to each other and will have a natural separation based on their shape.
Other pavers that are perfectly square will need spacers placed in between them. You might think it's better to place them right next to each other to prevent weeds from growing through, but this is a common mistake.
Not only will your stones get out of line quickly, spacers allow you to put polymeric or paver sand in between the joints to help eliminate weed growth.
Add Polymeric Sand
The next step to preventing weeds from growing in between pavers is to add polymeric sand to the joints. The application consists of pouring the sand between the joints and sweeping it into the crevices so that they are completely filled.
Tap on the pavers with a broom handle or like object as the vibrations will tamper the sand into place. Continue to add sand and tap until the joints are filled up to 1/8-inch below the top of the paver.
Polymeric sand needs to be watered after application to activate the polymers. Check the instructions of the bag for each product to see what it specifically requires as this step is very important for hindering weed growth, and getting a clean surface.
Is Paver Sand Just As Good?
Not everyone uses polymeric sand between pavers as some opt for regular paver or "all-purpose" sand. It comes down to personal preference and the job itself, as both have their pros and cons.
Polymeric sand is the stronger product when it comes to weed and pest control. Because of its strong polymer bonding agents, once it's been activated by water it becomes hard and gel-like, making it hard for anything to grow up through, or on top of the joint.
Polymeric sand lasts approximately ten years when applied properly, whereas regular sand needs to be touched up every few years, as wind and rain will naturally erode it.
There is the potential for polymeric sand to create a haze on the surface of pavers if not washed properly. This haze is difficult or sometimes impossible to clean off, potentially ruining pavers permanently. Regular sand does not have this issue and is not as fussy in terms of application.
While polymeric sand is long-lasting and durable, it will eventually get small cracks and need touching up, as well. There may be certain types of stones and pavers that are easier to fill with regular sand like flagstone, or anything else with a bumpy surface where the polymeric sand may be difficult to clean.
Apply a Sealant
Not everyone chooses to seal their pavers, but this extra step provides even more protection from weeds growing in the joints between your pavers.
Sealers help to harden the sand by adding a thin layer over the top that makes it difficult for anything to grow on top, or get underneath. This barrier also helps rain and water run off rather than seep into the paver joints, which will wash away weed seeds rather than absorb them.
It also provides general protection for the pavers themselves, as concrete is porous and can stain over time.
Pavers must be cleaned properly before sealing, and most manufacturers recommend waiting at least 90 days after applying polymeric sand. Always choose a high-quality product and follow the instructions on the bag.
Many DIY'ers make the mistake of using a different material as their base instead of gravel. Dirt or backfill are commonly used because they're often already on site and can be used for free.
Dirt will quickly shift over time, and your pavers will end up sinking and moving along with it. Eventually, your smooth, level surface will become bumpy, which will cause cracks and openings in the joints where weeds will gladly set up shop.
Some people also skip the compacting step, which will result in pavers that sink, or become uneven. Always compact the gravel base before laying pavers as it's a lot easier to do this step in the first place, than have to redo your entire project.
Take care in laying the pavers properly, as well, as rushing this step can result in scraping and pushing the sandy underlayment out of place. While the pavers may look even, any gaps or voids underneath them will eventually cause them to shift, creating havens for weeds to grow.
Where possible, avoid long sections of linear lines when installing your pavers. There are many different kinds of recommended paver patterns that will result in a strong bond that won't shift.
Long linear lines will shift easier than patterns where the pavers reinforce each other. There are a few rules to help guide the process: don't let linear lines run for more than eight feet, have a pattern in mind, and never have four corners meet.
Prevention After Installation
Using the best quality materials for your base and pavers will help ensure that weed growth is limited, but there are other ways to prevent weed growth after the installation has been completed.
As already mentioned, weeds are experts at growing in tough places, and even a few seeds can quickly mature into a full-on weed explosion.
Installing your patio with a proper slope is important so that water and rain run away from the foundation of the home. This also helps to keep weeds from setting up shop, especially on a properly sealed patio.
You can also practice good maintenance habits like regularly sweeping along joints or crevices where weeds could potentially grow. Even if you don't see any weeds, sweeping is a good idea: it just takes one seed to start a weed revolution.
How to Remove Existing Weeds
Even the best laid patios will eventually get weeds popping up in places, but you can keep them at bay, or deal with large infestations in a few different ways that don't require using nasty chemicals.
Removing weeds by hand is not only environmentally friendly, it's also a good way to ensure that you've got the entire root. Picking off the tops of weeds and leaving their taproot does little to fix the problem even though it might look better for a while.
Use gloves when pulling by hand, and be careful not to disturb any seeds on their flowers, as this is the most common way that weeds re-seed themselves.
For large-scale problems, a pressure washer can be helpful to remove surface-level weeds that don't have long taproots. Crabgrass and dandelions are better pulled, but purslane or other spreading weeds or moss can be washed away with a gentle, but effective amount of pressure - just don't blast them off too strong that you damage the joints or pavers themselves.
If large holes have been left over after removing weeds, fill in gaps with more of the sand that you used to fill the joints. Both polymeric and paver sand can be re-applied as needed.
Natural Weed Sprays and Solutions
There are some common household items or solutions that gardeners use in tough-to-get-at areas between pavers, but some of these are considered to be more effective than others.
Pouring boiling water over a weed is not recommended for a variety of reasons. Not only does it rarely work, it can damage the surface of your pavers, or scald you in the process.
A solution of vinegar and water has also been touted but has never been proven to be effective against all kinds of weeds. Vinegar can also stain certain kinds of stone.
There are a few herbicidal products on the market now that are safe to use around pets and humans, and aren't made of harsh chemicals. Look for environmentally friendly herbicidal soap solutions that will kill weeds on contact.
Just be careful not to spray around any plants you don't want to kill, and always check the product to make sure it's safe for use on concrete, and other kinds of masonry.
Even the best laid patio pavers will eventually suffer from weed growth, but the amount will be minimal compared to ones that are installed without weed prevention in mind.
The best ways to prevent weed growth between pavers is to do the work ahead of time so that any maintenance and weed removal years later will be easy to manage.