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Kill Weeds on Hard Surfaces

The A-Z of weed control on hard surfaces.

Of all the steps involved in maintaining a healthy and flourishing garden, controlling the invasion of unwanted weeds can sometimes seem to be an ongoing battle.

Not only your flower beds but every inch of your home is subject to be the unwilling home of daisy weed, ivy, thistle, and other creeping plant marauders.

How do we control the weeds that consistently sprout up through gravel, pavement, and other hard surfaces? What remedies are there for treating walls and roofs?

Aggressive weeds like the ones described here can quickly suffocate a garden’s roots and, to add insult to injury, threaten damage to your house and property as well.

On Driveways

Most small weeds are able to make their way through even the smallest cracks and openings. Even a newly paved and seemingly faultless concrete area is at risk for unwanted plant invasion.

Plant fibers are comprised of tightly packed cells that continually stack atop one another, forming a stalk strong enough to eventually penetrate even the strongest barriers.

Step One: Pull the Suckers

Use a weed knife to dig deep into cracks and pull weeds out by the roots. No need to worry about worsening any cracks as you dig; we will address that problem in Step Three.

 PRO TIP : 

Pouring boiling water directly onto weeds will quickly kill them and spare you the trouble of bending over quite a bit.

Step Two: Brine the Area

Pour a heavily saturated salt water brine to completely sterilize the ground and kill anything growing underneath.

You will not be able to see or reach the roots of plants hiding under the concrete, waiting to sprout up, so it is important to use saltwater as a far reaching remedy. Some online recipes include vinegar, a potent natural weed killer, but much too abrasive for concrete.

Step Three: Seal the Crack

Do It Yourself concrete sealing is quite affordable, durable, and easy to use. Sweep the area of debris, fill with caulk, and smooth down with a brush to finish. Sealant requires up to 24 hours to completely dry so make sure you choose a day when the weather is clear.


On Patios & Pavers

Your outdoor patio should be a comfortable lounging spot, and the unwelcome intrusion of weeds sprouting up from between the stones can be a quick spoiler.

Dandelions especially grow equally well in sun or shade, and are often the most prominent invaders. The deep roots and wildly spreading seeds will create a constant battle no matter how your patio is arranged. Fortunately, there is a permanent solution.

Step One: Pressure Wash

Always begin by pulling out larger plants by hand, being sure to completely remove the entire root. After that, you can quickly be rid of the smaller, harder to reach weeds by spraying between bricks with a pressure washer. Even if you do not have access to a pressure washer, you can repeat a simple method like this one to achieve the same results with a regular water hose.

PRO TIP:

Regular sweeping with a stiff brush will brush away seedlings and prevent them from sprouting & spreading.

Step Two: Treat the Cracks

You can repeat treatment with salt brine or boiling water if you prefer to remain as organic as possible. However there are multiple options for effective and environmentally safe chemical weed treatments, many of which come highly rated. The objective of course is to stop weed growth at the roots before it can spread.

Step Three: Seal Cracks with Polymeric Sand

Polymeric Sand is a cement like mixture ideal for quick do-it-yourself projects. You can create your own polymeric sand with products like ConSANDtrate. However, store bought is not usually very expensive and tends to yield stronger and longer lasting results.


On Walls

The small trail of ivy growing up your garden wall probably seemed rather attractive at first, but climbing weeds like wysteria and bindwood grow quickly out of control. Twining stems and tendrils can interlace between cracks in the foundation and weaken the entire structure while choking your most coveted garden plants.

Vines can grow so deeply embedded within the wall that pulling them out by hand becomes arduous. So difficult is the removal of wall climbers like ivy and creeping jenny, that in many places you can be sued or criminally charged for deliberately planting them.

Step One: Kill From the Root

Don your thickest pair of work gloves and get ready to carefully and painstakingly peel those pesky vines from your wall.

I say carefully because you have to be cautious of sharp thorns as well as spiders and other living creatures that love to nest within thick bundles of climbing vines.

I say painstakingly because vegetation deeply rooted in the foundation and between bricks can cause a structural collapse if you are too rough.

If the vines are just too strong to pull down, then sever the stems a few inches above the ground. Kill the roots with vinegar or weed killer, and later the detached vines will wither and fall away more easily.

Step Two: Spray With Caution

Once you’ve destroyed the roots, you can easily spray stalks with a vinegar solution and eliminate the infestation. However, this effective weed killer will also harm any other plant in your garden. Protect your other plants by covering the sprayer with a milk carton or, if you prefer, use a paintbrush to specifically mark only the areas you need treated.

Step Three: Poison the Roots for Good

In all of my research and experience, I believe this method for killing vine stubs is one of my favorites. Insert vine stubs into a recycled old soda can filled with a little sand and your preferred herbicide. Over the course of a week, the vine will deliver poison throughout the entire root system and kill your creeping invader once and for all.


On Block Paving

A garden lined with paths of block paving stones is both attractive and functional, but quickly prone to all manner of detritus that accumulates between cracks. Seeds easily become cradled in the crevices between bricks and with a little rain the moisture rich environment becomes a perfect spot for all the most common weeds.

Step One: Flame On!

Any of the aforementioned methods for weed pulling is acceptable in this situation of course. However, if you have had your share of water hoses and garden picks, you might find it entirely effective (and maybe somewhat satisfying) to start torching your weeds. A propane powered weed torch, is a handy alternative for the gardener who has tried everything.

Step Two: Clean and Dry

High moisture also makes block paving an ideal spot for mold and algae. There is no need for chemicals here, simply scrub with soap and water and make certain the area gets plenty of sun to keep dry. A well designed garden will include a way for excess water to run off instead of creating standing pools.

Step Three: Seal the Cracks

EnviroSand is a highly rated filler designed to fill and seal the cracks between block paving and prevent new weeds from sprouting. Unlike the polymeric sand described above, EnviroSand is held together with an organic plant glue. The result is a firm but flexible gel that resists erosion and cracking better than cements and polymerics.


On Roofs

Your roof is prone to catching fallen leaves and other loose debris that will combine with rain water to create a fertile compost heap on your shingles. You will usually see thick patches of moss and lichens accumulating on rooftops. The effect will at first seem like a harmless discoloration, but given time the unwanted plant growth will split cracks in your shingles, causing leaks and other expensive damages.

Step One: Remove All Debris

You will be spared a lot of hardship simply by keeping your roof free of debris. Homes in areas that are high in moisture and surrounded by trees are most at risk for damaging weeds on the roof. If you feel wary about climbing on your own roof, it is totally acceptable to hire a professional. Regardless of your situation, regular roof cleaning is a highly recommended measure for homeowners everywhere.

Step Two: Spray with Cleaners

Roof cleaning solutions are available in a number of convenient Do-It-Yourself recipes. Many store bought cleaners can be easily attached to a sprayer nozzle on your hose. Pages like this one provide detailed directions on thoroughly effective roof cleaners.

Step Three: Install Zinc Strips

Zinc strips on the roof are affordable and easy to install. When it rains, particles of zinc will be washed over your shingles and spread over your roof. The resulting barrier makes it difficult for mosses and lichens to accumulate.

PRO TIP: Remember that an ounce of prevention is worth a pound of cure. Install zinc strips early, especially if you live in a mold prone area, and eliminate the problem before it starts.


In Gutters

As you focus on your home garden, you may be unintentionally fostering a gutter garden. Inefficiently running drainage can cause pools of standing water and a collection of compost and rotting leaves perfect for growing weeds. Not only are gutters a perfect housing for ivy, thistle, and algae, but even tree saplings can easily take root and grow to damaging sizes.

Step One: Clean Your Gutters

Fortunately, as long you flush them out early, your gutter weeds will not have far to go. You can clean out gutters by hand or take advantage of several useful tools all designed to aid us with this most dreaded of chores.

Step Two: Protect Your Gutters

Many homeowners choose to install gutter protectors, mesh covers that allow rain water to pass through while keeping out the leaves and debris that encourage weeds. Make sure your gutters are thoroughly cleaned before you install, and continue to regularly check for blocks.


Under Decking

The main difficulty with weeding under decks is that in many cases your deck is too low to comfortably walk underneath and too high to easily reach weeds through the slats. The result is an unkempt area of growth just under your feet. Many of these shade friendly perennials have deep roots and are difficult to completely destroy. However, you can keep them under control.

Step One: Pull What you Can

If you have room to reach between the boards start by pulling up as many of the larger weeds that you can. You can use a long handled weed puller through the slats to take out as many plants as you can.

Step Two: Stop Watering

Your sprinkler system may be unintentionally supplying the forest of vegetation under your deck. After you treat the area with any of the aforementioned herbicides, take a moment to investigate the irrigation system in your yard. Is runoff regularly collecting under the deck? Redirect that water flow or stop it entirely.

Step Three: Smother

You can smother the growth of problematic weeds by placing a barrier (or mulch). Clear as much of the area as you can, securely pin down a thick landscaping fabric, and cover with mulch, rocks, or pebbles. Landscaping fabric is not a guaranteed hold against weeds because seeds can still collect on top, but you can successfully slow the weeds to a more manageable pace.


On Tarmac

The same dandelions and thistle that emerge between cracks in the tarmac are prone to show up just about anywhere. The most aggressive weeds thrive by producing seeds that float and spread throughout the area, able to plant anywhere they land.

Step One: Pull

Using the same methods mentioned above, pull as many weeds as you can by hand.

Step Two: Corn Meal

You can also use any of the previously mentioned remedies or your preferred herbicide, but an additional organic weed killer is corn meal. Sprinkling corn gluten meal stops weed seeds from germinating. Be sure to use it properly though.


On Gravel Areas

Gravel of course leaves many open crevices for faling seeds to become safely lodged and enjoy access to plenty of light and water. Fortunately, these weeds tend to have shallow roots and are easily treated.

Step One: Brine

Unlike brick and asphalt that must be safely cleansed, you can rinse your gravel in a saturated brine without causing any damage. Combine salt, vinegar, and dish soap for a deadly weed killer. As always, keep your other plants safely protected because these concoctions kill anything they touch.

Step Two: Recover

Gravel needs to be occasionally refilled as it gets washed away by rain and worn down by people and vehicles. The next time you reline your gravel, take a moment to place down a sturdy weed barrier. PRO TIP: Always use heavy vinyl fabric, never plastic, for landscape cloths.


On Paths

Your path can be treated in anyway according to the many suggestions listed above. Treating concrete, gravel, or paver stones is all much the same whether you are covering a large are or a narrow path.

 PRO TIP: 

Remember to protect your desired plants when you spray paths. A sheet of cardboard between the path and your plants can keep you from unintended losses.

I hope you have enjoyed my compilation and that its many resources will help you. For me, weed control has always been a crucial part of maintaining a healthy, vibrant garden. More so, I prefer methods that simpler, more natural, and more gentle on the Earth. Please feel free to comment below and share this information with anyone that may find it useful.Jump to top

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About the Author

Hey there, I am founder and editor in chief here at Good Grow. I guess I've always known I was going to be a gardener. I'm on a mission to share my expertise and insider weed control tips with you all.