Scrape or hand-pull small patches, use a proper crevice tool for larger areas, and spot-spray stubborn perennials that keep returning. For recurring or large-scale infestations across car parks, footpaths or solar sites, a professional or robotic spraying service is the more reliable fix. Whatever method you choose, always follow label directions, and pair removal with sealing or repointing so the weeds do not just come back.
TL;DR:
- Manual tools are suitable for small patches under 50 square centimeters, while large or recurring infestations typically require professional or robotic spray services.
- Spot-spraying with glyphosate-based products offers the most long-term efficiency for deep-rooted perennials on extensive or high-maintenance sites.
- Repeated thermal or non-chemical methods can damage delicate surfaces and are less effective against established perennials, necessitating regular treatment.
- Proper joint sealing with flexible or rigid materials, along with routine maintenance, is essential to prevent weed recurrence in cracks.
- Contracted services with site assessments and pilot programs are recommended for large-scale, high-traffic, or hard-to-access areas to reduce ongoing labor and maintenance costs.
Table of Contents
- At-a-glance methods: pros, cons and how quickly they work
- Tools and step-by-step technique for removing weeds from narrow cracks
- When to use spot herbicides and how to apply them safely
- Thermal and other non-chemical methods: effectiveness and limitations
- How to stop weeds coming back: sealing, repointing and routine maintenance
- Safety and environmental considerations when treating cracks and crevices
- When to call a professional: robotic and contracted options
- Author perspective: why integrate DIY, prevention and professional contracts
- How BrightView can help with crack and crevice weeds at scale
- Sources
- FAQ
At-a-glance methods: pros, cons and how quickly they work
The right method depends on how much area you are treating, what species you are dealing with, and how much ongoing maintenance you are willing to do. Matching the method to the job saves time and stops you damaging pavers or exposing yourself to unnecessary chemical use.
- Manual scraping or pulling: best for seedlings and hairline joints, cheap but slow across large areas.
- Mechanical crevice tools and brushes: faster for footpaths and driveways, though repeated brushing can wear softer paving materials.
- Spot-spraying: the most effective option against deep-rooted perennials, but drift and run-off control matter on hard surfaces.
- Thermal or hot-water treatment: quick against young annuals, less consistent on established perennials and risky on fragile or heat-sensitive surfaces.
As a rough guide, a patch under 50 square centimetres is a job for a hand tool. Anything spanning several square metres usually calls for a mechanical crevice tool or a spot treatment. Where the same cracks keep filling with weeds season after season across a large property, that is the point where a contracted or robotic spraying programme starts to make more sense than repeat DIY visits. A Wageningen University & Research study found that non-chemical methods on pavements are generally less effective and more labour-intensive than spot-spraying, and that non-chemical regimes often cost significantly more over time to maintain the same low weed cover.
That single finding shapes most of the advice below: manual and mechanical work well for small jobs and prevention, but spot-spraying tends to be the more efficient long-term technique once an area grows beyond what you can comfortably manage by hand.
Tools and step-by-step technique for removing weeds from narrow cracks
Joint width decides which tool actually works. A hairline crack under 3 millimetres needs something thin and rigid; a narrow joint of 3 to 10 millimetres suits a dedicated crevice weeder; anything wider than 10 millimetres can take a hoe-style paving knife or a stiff wire brush.
- Wet the soil first. A light watering the night before, or after rain, loosens compacted soil around the roots and makes extraction far easier.
- Loosen the root zone. Slide a block paving knife or crevice tool along both sides of the weed to break the soil’s grip without gouging the paver edge.
- Lever, don’t yank. Pull steadily along the root line so the taproot comes out whole rather than snapping off below the surface.
- Remove seedheads immediately. Bag any flowering or seeding growth on the spot so you are not reseeding the joint as you work.
- Clean out the joint. Brush out loose soil and root fragments so the crack does not simply refill with a fresh seed bed.
- Dispose offsite. Take pulled weeds and seedheads to green waste rather than leaving them on the verge or in a garden bed.
This sequence matches practical hard-surface guidance from Cornell’s turfgrass and weed identification programme, which recommends wetting soil before lifting tap-rooted weeds and using block paving knives and brushes to clean the joint afterwards. The same source notes that simple habits, regular sweeping and keeping soil out of joints, cut down materially on how often active treatment is needed at all.
Tool care matters more than most people expect. A blunt paving knife tears roots instead of cutting them, leaving fragments behind that regrow within weeks. Sharpen a steel crevice tool with a flat file every few uses, wipe the blade dry after each job to stop rust, and store it away from damp garden sheds. A stiff paving brush should be rinsed of soil and grit after use; bent or splayed bristles stop clearing joints properly and are worth replacing rather than persisting with.
Pro Tip: For long taproots such as dandelion or plantain, use a hooked weeding knife and work from both sides of the crack rather than levering from one direction only, which reduces the chance of chipping the paver edge.
When to use spot herbicides and how to apply them safely
Spot-spraying beats broad application on hard surfaces because you are treating only the plant and the joint around it, not the whole path or car park. That precision means less total chemical used for the same result, which matters both for cost and for run-off risk near drains, gardens and waterways.
Most spot treatments for hard surfaces use glyphosate-based products or other actives registered for non-crop or industrial areas. The product label is the only reliable source for rate, timing and which surfaces or situations it is approved for, and Australian label instructions must be followed exactly, including any restrictions on use near water or in council-managed public areas.
- Choose the right applicator: a pump-up sprayer suits larger areas, a bottle or wand applicator gives more control on isolated cracks, and a wicking or gel applicator limits contact to the target plant.
- Check the weather first: avoid spraying in wind, and skip treatment if rain is forecast within the label’s stated window, since run-off carries herbicide straight into stormwater.
- Prevent run-off onto garden beds or drains: treat only the crack itself rather than saturating surrounding pavement.
- Try mechanical removal first on small, isolated weeds: herbicide is best reserved for deep-rooted perennials or areas too extensive to hand-weed economically.
For sites where spot-spraying needs to happen repeatedly across a large footprint, such as car parks, footpath networks or land around solar infrastructure, selective weed spraying delivered as a managed service reduces the drift and consistency problems that come with ad hoc manual application. Further detail on drift-reduction technique is covered in BrightView’s spot-spraying technology guide.
Thermal and other non-chemical methods: effectiveness and limitations
Flame weeding and hot water both work by rupturing plant cell walls with heat, which wilts and kills young annual weeds within a day or two. Established perennials with deep taproots are a different story: the visible top growth dies back, but the root often survives and resprouts within weeks, meaning repeat treatment is normal rather than a sign you did it wrong.
A 2007 review of non-chemical weed control on hard surfaces found that mechanical brushing, thermal treatment and spot herbicide each have contexts where they perform best, with corresponding limits around surface wear or weed tolerance. That review reinforces the trade-off seen in the pavement research above: non-chemical methods generally need more frequent repeat visits than a well-timed spot treatment.
- Flaming: fast on seedlings and annual grasses, ineffective against most established perennials.
- Hot water or steam: similar results to flaming, with less fire risk near flammable surfaces or vegetation.
- Mechanical brushing: useful for loosening surface growth and soil, but repeated brushing wears asphalt, thin paving and jointing sand over time.
- Rotation matters: alternating methods rather than relying on one approach reduces the chance of favouring weed species that tolerate that specific treatment.
Asphalt and thin decorative paving are the surfaces most at risk from repeated thermal or brushing treatment, so it is worth testing on a small section before committing a whole path or car park to one method. Larger sites juggling multiple pavement types are where a mixed non-chemical and spot-spray programme, covered in more detail on BrightView’s non-chemical weed control page, tends to hold up better than a single method applied everywhere.
How to stop weeds coming back: sealing, repointing and routine maintenance
Removing the weed only solves half the problem. If the joint still holds soil, moisture and light, seed will find its way back within a season. The fix depends on whether the crack is static or moving.
- Static cracks: polymeric sand or a rigid mortar repointing works well because the joint is not flexing.
- Dynamic cracks: flexible sealants cope with ongoing movement from temperature change or ground settlement, where a rigid fill would just crack again.
- Routine sweeping: clearing organic debris and soil out of joints before it builds up denies weed seed a place to establish.
- Watch for recurring growth in the same spot: it often points to drainage or soil accumulation rather than fresh seed blowing in.
RHS guidance on hard-surface weeds recommends block paving knives and stiff brushes for removal, followed by repointing or polymeric sand as the prevention step once the joint is clean. Where a crack near a stone or masonry feature keeps failing despite repointing, a homeowner’s guide to sealing natural stone covers the broader maintenance routine that keeps joints and surfaces intact.
For larger assets, persistent weed growth around the same posts, footings or pavement sections is often a sign of a structural issue, drainage pooling, subsidence or a joint that needs regrading rather than just re-treating. Guidance on avoiding repeat restoration costs around infrastructure is set out on BrightView’s post-area weed control page.
Safety and environmental considerations when treating cracks and crevices
Label directions exist for a reason: they set the PPE, application rate and buffer distances that keep the treatment effective and legal. Avoid spraying near stormwater drains, waterways or garden beds you want to keep, and check restrictions before treating footpaths in shared or public areas.
- Wear the PPE the label specifies, even for small spot jobs, since concentration and skin contact risk are the same regardless of area treated.
- Wash tools after use and avoid tipping leftover mixed herbicide or rinse water down a drain.
- Test thermal tools and new products on a small, inconspicuous section first to check for surface damage before treating a whole area.
- Bag and bin pulled weeds and seedheads rather than composting them if they have already flowered or set seed.
A local government noxious and environmental weed control handbook is a useful reference if you are unsure whether a species growing in your pavement is a regulated weed that needs reporting rather than routine removal.
When to call a professional: robotic and contracted options
Some situations tip past what regular DIY maintenance can handle: large car parks, extensive footpath networks, restricted-access areas around solar arrays, or sites where regulatory compliance and consistent record-keeping matter as much as the weeds themselves.
- Scale and recurrence: if the same cracks need retreating every few weeks across a large site, a scheduled programme is more efficient than repeat manual visits.
- Restricted or hazardous access: areas under solar arrays or around live infrastructure are safer for autonomous equipment to reach than for staff on foot.
- Consistent targeting: robotic selective spraying applies treatment repeatably to the same crevices, cutting down on missed patches and manual labour hours.
- Compliance needs: asset managers and councils often need documented, repeatable treatment records that a contracted service can provide.
A typical starting point is a site assessment, an inspection of pavement types, weed pressure and access constraints that feeds into a tailored control plan, often trialled through a pilot phase before a full contract begins. Readers managing larger sites can review BrightView’s selective weed spraying service or request a site assessment directly.
Author perspective: why integrate DIY, prevention and professional contracts
Most crack weed problems are not really about which tool pulls the weed fastest. They are about whether anyone addresses the soil, drainage and jointing that let the weed grow back within weeks. Treat recurring growth as a maintenance signal, not a cosmetic nuisance, and you spend far less over the life of the asset than chasing the same cracks every season.
— BrightView
How BrightView can help with crack and crevice weeds at scale
For asset managers and councils dealing with pavement networks, car parks or land around solar infrastructure, hand tools and one-off spraying only go so far. BrightView’s selective weed spraying applies treatment precisely to crevices and joints across large sites, backed by a site assessment that maps weed pressure and access constraints before any work begins.
- Site assessment: an inspection of your pavement, joints and vegetation pressure that shapes a tailored control plan.
- Selective weed spraying: targeted treatment of crevices and hard-surface joints across footpaths, car parks and solar sites.
- Vegetation management under solar arrays: ongoing control in areas that are difficult or unsafe to access on foot.
- Pilot programmes: a trial phase to validate results on your site before committing to a full contract.
If recurring crack weeds are costing your team repeat call-outs or putting pavement condition at risk, request a site assessment or ask about a pilot programme to see how a contracted approach compares with your current routine.
Sources
Claims in this guide draw on hard-surface weed research from Wageningen University & Research and a Wiley review of non-chemical control methods, alongside practical guidance from Cornell’s turfgrass programme and the RHS. For broader prevention philosophy, an IPM overview of eco-friendly pest control covers similar rotational thinking.
- Effectiveness of weed control methods on pavement – Research Portal – Wageningen University & Research
- A review of non‐chemical weed control on hard surfaces – Wiley Online Library
- Weeds on hard surfaces – RHS
- Hard surfaces | Turfgrass and Landscape Weed ID – Cornell
FAQ
How do you get weeds out of crevices?
Wet the soil first, then use a block paving knife or crevice weeder to loosen the root before pulling it out whole. Clean the joint of remaining soil and root fragments afterwards so it does not immediately refill with a fresh seed bed, following the approach set out in Cornell’s hard-surface guidance.
What kills weeds growing in cracks?
Manual removal handles seedlings and light growth, while spot-applied herbicide is generally the most effective option against established, deep-rooted perennials on hard surfaces. A Wageningen University & Research study found spot-spraying outperforms non-chemical methods for maintaining low weed cover over time.
Do crack weeders work?
Yes, a dedicated crevice weeder or block paving knife is effective for lifting weeds from narrow joints, particularly once the soil has been wetted to loosen the root’s grip. They work best on isolated weeds and small to medium areas rather than extensive infestations across a whole site.
What is the best tool for getting weeds out of cracks?
The right tool depends on joint width: a thin rigid blade suits hairline cracks under 3 millimetres, a hooked crevice weeder suits joints of 3 to 10 millimetres, and a paving knife or stiff wire brush handles wider joints. The RHS recommends block paving knives and stiff brushes as the standard hand tools for this job.
When should I hire a professional instead of doing it myself?
Once the same cracks need retreating every few weeks, or the area spans a large car park, footpath network or solar site with restricted access, a contracted or robotic spraying programme becomes more practical than repeat manual visits. Asset managers can start with a site assessment to scope a tailored control plan.
