Salt Kills Moss. It Also Kills Your Garden For 3 Years.
Yes, salt kills moss. It also kills every plant it touches, sterilizes your soil for years, contaminates your water table, attracts wildlife that spreads it further, and leaves white crusty deposits on paving that never wash away. That £2 bag of salt could cost you £500+ in dead plants and soil remediation.
What happens when you use salt on moss:
- X Soil becomes sterile (nothing grows there for 2-3 years)
- X Plants within 1-2 meters die from salt runoff
- X White salt deposits cake onto paving permanently
- X Groundwater contamination (enters local water systems)
- X Attracts deer, rabbits, cats who spread it across your garden
- X Metal corrosion on garden furniture and fixtures
Why Professional Landscapers Banned Salt Decades Ago
Professional landscapers stopped using salt in the 1980s when they realized the long-term damage destroyed their clients’ gardens. They switched to targeted moss killers that work faster, safer, and don’t leave behind environmental catastrophes. The only people still using salt are DIYers who don’t know the consequences yet.
The professional solution that won’t destroy your garden:
– Kills moss in 24-48 hours (same as salt)
– Safe for soil, plants, and grass
– No contamination or side effects
– Your garden survives the treatment
*Because replacing dead plants costs more than proper moss killer.*
Still considering salt? Read about the permanent damage below…
How Salt Kills Moss (And Everything Else)
Salt kills moss through desiccation. When you sprinkle salt on moss, it draws moisture out of the moss cells through osmosis. The moss dehydrates, browns, and dies within a few days.
Sounds perfect, right?
The problem is that salt doesn’t stop at moss. It continues drawing moisture from everything it touches – plant roots, beneficial bacteria, earthworms, insects, and soil microorganisms. Salt is indiscriminate. It’s a biological scorched-earth weapon.
When you use salt to kill moss, you’re not selectively removing one problem plant. You’re creating a dead zone where nothing can grow for years.
The Soil Sterilization Problem
Healthy soil is alive. One teaspoon of garden soil contains more living organisms than there are people on Earth. These organisms break down organic matter, cycle nutrients, and create the conditions plants need to thrive.
Salt kills them all.
What Happens to Salt-Treated Soil
Week 1-2: Moss dies. You feel victorious. Salt dissolves into soil.
Month 1: Plants near treated areas start showing stress – yellowing leaves, wilting, slow growth. Salt has reached their roots through water movement.
Month 2-3: More plants die. Earthworms disappear. Soil becomes hard and crusty. Nothing new will grow in the treated area.
Month 6-12: Salt concentration begins to dilute through rainfall and leaching, but soil biology remains devastated.
Year 2-3: Soil slowly recovers biological activity, but salt effects persist. Some plants still struggle in the area.
You wanted to kill moss on your patio. You’ve accidentally sterilized the soil for years.
The Runoff Disaster
Salt doesn’t stay where you put it. It’s highly water-soluble and mobile. When it rains – which in Britain happens constantly – salt washes into surrounding areas:
Lawn damage: Salt runoff kills grass in a 1-2 meter band around treated areas. You end up with dead grass strips that take months to recover.
Garden bed contamination: Salt flows downhill into flower beds, vegetable gardens, and planted areas. Plants you’ve carefully cultivated for years die from salt poisoning.
Drainage system pollution: Salt enters drains, storm sewers, and eventually local waterways. Aquatic ecosystems are extremely sensitive to salinity changes.
Groundwater contamination: In areas with porous soil, salt leaches into groundwater, affecting water quality for everyone in your area.
One person using salt on their patio moss creates contamination that affects their entire property and beyond. Understanding how moss establishes and spreads shows why preventing runoff damage matters – you’re trying to solve one biological problem while creating several others.
The Wildlife Attraction Problem
Here’s something nobody mentions about using salt outdoors: animals love salt.
Deer, rabbits, squirrels, foxes, badgers, and even domestic cats and dogs seek out salt deposits. When you sprinkle salt on moss, you’ve created a salt lick in your garden.
What happens next:
- Animals lick the salt-treated areas
- They walk through the salt, getting it on their paws
- They track salt across your entire garden
- They return repeatedly because salt sources are valuable to them
- Your targeted moss treatment becomes garden-wide contamination
Deer are particularly problematic. A deer that finds your salt-treated patio will visit nightly, spreading salt throughout your property and potentially causing far more damage than the original moss problem.
The Permanent Staining Issue
On paved surfaces, salt creates white crystalline deposits that are nearly impossible to remove. These aren’t dirt that can be washed away – they’re salt crystals that have bonded into the porous structure of concrete, bricks, and stone.
Types of permanent staining:
Efflorescence: White powdery deposits that appear as salt recrystallizes on the surface. Washing removes surface layer, but more keeps appearing from deeper in the material.
Salt creep: White streaks and patches where salt has migrated through porous materials. Permanently alters appearance of paving.
Color bleaching: Salt can actually lighten colored pavers and bricks, creating permanent discoloration.
You wanted to improve your patio’s appearance by removing moss. You’ve permanently stained it with white salt deposits that look terrible and never fully disappear.
The Metal Corrosion Factor
Salt accelerates corrosion of any metal it contacts. Garden furniture, railings, fence posts, outdoor lighting, drainage covers, and embedded metal in concrete all corrode faster when exposed to salt.
Real-world impacts:
- Metal garden furniture develops rust spots within weeks
- Gate hinges and latches corrode and fail
- Outdoor lighting fixtures deteriorate
- Rebar in concrete begins rusting, causing spalling
- Decorative metal features tarnish and pit
The corrosion damage from salt moss treatment can cost hundreds in repairs and replacements.
Real Stories: When Salt Goes Wrong
The dead garden border: Homeowner spreads salt on patio moss. Rain washes salt into adjacent flower bed. Entire border of established perennials dies within three weeks. £300+ in plant replacement costs.
The white-stained driveway: Salt applied to driveway moss creates permanent white streaks. Pressure washing, acid washing, and grinding all fail to remove them. Driveway looks worse than with moss. Would cost £2000+ to resurface.
The poisoned lawn: Salt used on path moss runs off onto lawn during rain. Creates 1-meter-wide dead strip along entire path length. Takes two growing seasons to fully recover.
The deer visitors: Salt on patio attracts deer. They return nightly, trampling garden beds and stripping young plants. Original moss problem solved, new deer problem created that’s far worse.
The contaminated soil: Heavy salt application kills moss but also sterilizes soil underneath paving gaps. When homeowner tries to plant between pavers, nothing grows for two years despite repeated soil amendments.
These aren’t rare disasters. They’re typical outcomes of using salt for moss control in garden environments.
Why “Rock Salt” Is Even Worse
Some people use rock salt (halite) or de-icing salt for moss because it’s cheap and readily available. This is exponentially worse than table salt.
Rock salt and de-icing salt contain:
- Sodium chloride (the harmful part)
- Anti-caking agents
- Corrosion inhibitors (ironically making garden corrosion worse)
- Sand and grit
- Heavy metal contaminants
The additional chemicals and contaminants make rock salt even more damaging to plants, soil, and water systems than pure table salt.
The “But It’s Natural” Fallacy
Salt advocates often argue “salt is natural, therefore it’s safe.” This logic is fundamentally flawed.
Many natural substances are toxic in the wrong context:
- Arsenic is natural (deadly poison)
- Mercury is natural (severe neurotoxin)
- Lead is natural (causes brain damage)
- Salt is natural (soil and plant killer)
“Natural” doesn’t mean “safe” or “appropriate to dump on your garden.” The right amount of salt is essential for life. Too much salt creates biological dead zones. Similar care is needed when treating moss on patios – the method matters more than whether it’s “natural.”
What Professional Moss Killers Do Differently
Modern moss treatments work through completely different mechanisms than crude salt desiccation:
Selective targeting: Formulated to affect moss biology specifically without harming other plants or soil organisms.
Biodegradable chemistry: Break down into harmless compounds within days or weeks, not persisting for years.
No soil damage: Don’t disrupt soil structure, salinity, or biological activity.
Controlled application: Can be applied precisely to moss without creating runoff contamination.
Surface safe: Don’t stain, bleach, or damage the materials they’re applied to.
Metal safe: Don’t accelerate corrosion of garden fixtures and furniture.
Professional moss killers cost more initially but avoid all the expensive problems salt creates. The total cost of salt treatment – including plant replacement, soil remediation, and permanent staining – always exceeds the cost of proper moss killer.
If You’ve Already Used Salt (Damage Control)
If you’ve already applied salt to moss, here’s how to minimize ongoing damage:
Immediate actions:
- Stop any further salt application
- Water the area heavily to dilute and flush salt deeper into soil (away from plant roots)
- Continue watering daily for a week to promote salt leaching
- Remove dead moss manually to prevent it holding salt
Longer-term remediation:
- Apply gypsum (calcium sulfate) to help displace sodium and improve soil structure
- Add organic matter to help rebuild soil biology
- Test soil salinity before attempting to replant
- Choose salt-tolerant plants for the first year in affected areas
- Be patient – full soil recovery takes 2-3 years
Even with aggressive remediation, some damage is permanent. Prevention is always better than cure.
Surfaces Where Salt Is Particularly Damaging
Salt causes problems on any surface, but some materials suffer worse damage. Garden paths with adjacent planting are at high risk because salt runoff directly reaches plant roots. Wooden fencing is another concern – salt accelerates wood decay while corroding any metal fixings, potentially reducing fence lifespan by years.
The Bottom Line: Salt Is Environmental Vandalism
Using salt to kill moss is environmental vandalism disguised as garden maintenance. You’re not solving a problem – you’re creating multiple worse problems that persist for years.
Salt damages:
- Soil biology and structure (2-3 year recovery)
- Plants within runoff range (immediate to months)
- Paved surfaces (permanent staining)
- Metal fixtures (accelerated corrosion)
- Water systems (contamination)
- Wildlife (attraction and spread)
All to kill moss that could be eliminated safely with proper treatment.
The reason professional landscapers abandoned salt decades ago isn’t because they’re trying to sell expensive products. It’s because they learned through bitter experience that salt causes far more damage than the moss it kills. The same lesson applies when dealing with moss in lawns – crude methods cause collateral damage that exceeds the original problem.
You can learn from their experience, or you can repeat their mistakes. But at least now you know exactly what you’re signing up for if you choose salt.
Final thought: If salt was an effective, safe moss killer, professional landscaping companies would use it exclusively because it costs 20p per kilo. The fact that they refuse to touch it should tell you everything you need to know about salt as a moss control method.
