6 Non-Selective Grass Weed Killers For Hardscaping That Old-Timers Swear By

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Tackling Weeds in Pavers and Gravel Paths

Weeds in hardscaping are a different beast than those in your garden beds. The roots anchor themselves in the tightest spaces, making them nearly impossible to pull cleanly. You’re not trying to preserve the soil for future planting; you’re trying to maintain a clean, functional surface.

This is precisely where non-selective herbicides and methods come into play. A non-selective killer doesn’t distinguish between a dandelion and a blade of fescue grass—it targets any plant it contacts. Choosing the right tool for the job depends on your tolerance for chemicals, the persistence of your weeds, and whether you want a quick fix or a long-term solution.

The Boiling Water Method for Instant Weed Wilting

The simplest method is often the most overlooked. A kettle full of boiling water poured directly onto weeds in sidewalk cracks or between pavers will scald them instantly. The heat ruptures the plant’s cell walls, causing it to wilt and die within hours.

This is a fantastic, zero-cost option for small, isolated patches of annual weeds. However, it’s a contact-only solution. It won’t do much to deep-rooted perennials, which will likely regrow from the root. It’s a temporary fix, best for quick touch-ups before guests arrive, not for clearing a long, weed-infested driveway.

Harris 20% Vinegar for an Acid-Based Burn Down

When people talk about using vinegar as a weed killer, they aren’t talking about the stuff in your pantry. Horticultural vinegar, at 20% acetic acid or higher, is a potent contact herbicide. It works by stripping the waxy, protective coating off plant leaves, causing them to rapidly dehydrate and die back.

On a hot, sunny day, the results are dramatic and fast. You can spray in the morning and see shriveled weeds by the afternoon. This makes it great for clearing out gravel paths or paver joints for a clean, immediate look.

But remember, this is a "burn down" application. It only kills the top growth it touches. Tough perennial weeds with established root systems will almost certainly come back. It’s also acidic enough to corrode metal parts on your sprayer over time and can etch concrete or stone with repeated use, so rinse your equipment and surfaces well.

Red Dragon Weed Dragon for Flame Weeding Control

For a chemical-free approach with a bit of firepower, flame weeding is incredibly effective. A tool like the Red Dragon Weed Dragon uses a propane torch to superheat the weeds. You aren’t trying to incinerate them to ash; a quick pass is all it takes to boil the water inside the plant cells, causing them to burst. The weed wilts and dies within a day.

This method excels in large areas like long gravel driveways where spraying liquids would be tedious. It works on young weeds and can set back tougher perennials. Plus, you can use it in damp conditions when a spray-on herbicide wouldn’t stick.

The primary consideration is, of course, fire safety. This is not a tool for windy days or drought conditions. Keep it far away from dry grasses, wooden fences, siding, and mulch. Always have a hose or fire extinguisher at the ready. It’s a powerful and satisfying tool, but one that demands your full attention and respect.

Using Rock Salt for Long-Term Bare Ground Areas

Salt is one of the oldest herbicides in the book for a reason: it works. By applying rock salt or making a strong saltwater brine, you create a toxic environment in the soil that dehydrates plants and prevents future growth. This is not a quick knockdown; it’s a long-term strategy for soil sterilization.

Use this method only in places where you want nothing to grow for a very long time. Think deep in a gravel driveway, along a foundation, or under a deck. It’s an effective way to create a permanent, vegetation-free zone.

The biggest danger with salt is its mobility. Salt dissolves in water and will travel with runoff. If you apply it on a sloped driveway, the next heavy rain could wash it into your lawn or flower beds, killing everything in its path. It is a powerful tool, but its effects are lasting and can spread beyond your intended target area. Use it with extreme caution and foresight.

This is a scorched-earth tactic. Once you salt the soil, you are committing that piece of ground to being barren for seasons, if not years. There’s no easy way to undo it.

Compare-N-Save 41% Glyphosate for Tough Roots

Sometimes, you face weeds that just won’t die. For deeply rooted, persistent perennials like poison ivy, stubborn thistle, or invasive grasses, a systemic herbicide containing glyphosate is often the most effective tool. Unlike contact killers, glyphosate is absorbed by the leaves and travels through the plant’s vascular system all the way down to the root tips, killing the entire plant.

This is the key difference: it eliminates the problem at the source. While salt and borax sterilize the soil, glyphosate binds to soil particles and is broken down by microorganisms, allowing you to replant in the area later if you choose. It’s for when you need to kill the plant, not the soil itself.

There is significant debate surrounding glyphosate, and its use is a personal decision. If you do choose to use it, responsible application is everything. Spray on a calm, windless day to prevent drift onto desirable plants. It works best when weeds are actively growing.

Most importantly, read and follow the label directions precisely. The label is the law and provides critical information on mixing rates, application, and safety precautions. This is not a product to be used carelessly.

A 20 Mule Team Borax Solution for Persistent Weeds

Found in the laundry aisle, borax is a naturally occurring mineral compound (sodium borate) that doubles as a potent, slow-acting herbicide. When mixed with water and applied to weeds, it is absorbed and disrupts their internal systems, leading to a slow but certain death. It functions much like salt, remaining in the soil to prevent new growth.

A common recipe is to dissolve 10 ounces of borax powder in about 2.5 gallons of water. This solution is best for spot-treating weeds in sidewalk cracks or along the edges of a patio where you want long-term control. It’s less effective on a broadcast scale but excels at targeted application.

Like salt, borax will render the soil sterile for a long time. It should be used with the same precautions, keeping it well away from the root zones of trees, shrubs, and garden beds. Runoff is a major concern, so avoid using it on slopes or before a heavy rain is forecast.

Proper Application and Soil Salinity Precautions

The most important lesson with these old-timer methods is that "natural" does not always mean "safe." Salt, borax, and high-strength vinegar can do lasting damage to your soil and surrounding ecosystem if used improperly. The principle of "right tool, right place" is paramount.

Always think about where water flows on your property. A treatment applied to a gravel path can easily wash into your lawn during a storm, creating dead zones. For soil sterilants like salt and borax, it’s better to create a small trench or physical barrier to contain them if you’re working near valued plants.

For any liquid spray, whether it’s vinegar or glyphosate, wind is your enemy. Even a slight breeze can carry droplets onto your prized tomatoes or the neighbor’s rose bushes. Use a coarse spray setting rather than a fine mist, and consider using a cone shield on your sprayer nozzle to direct the application exactly where you want it. With any of these methods, start with the lowest effective dose. You can always apply more, but you can’t undo an overapplication.

The best approach is a thoughtful one, matching the method to the specific problem, location, and your long-term goals for the area. Whether you choose to burn, scald, or spray, understanding how each tool works—and its potential consequences—is the key to winning the war on weeds in your hardscaping.