The Best Rock Salt for Killing Weeds Effectively

Weeds are the bane of many gardeners’ existence. They pop up uninvited, stealing water, nutrients and space from your precious plants. While hand pulling weeds works for small infestations, severe cases call for a stronger solution. This is where using rock salt as an herbicide comes in handy. Keep reading to learn why salt kills weeds, the best type to use and how to apply it safely in your garden.

Why Salt Kills Weeds

Table salt contains high concentrations of sodium chloride, which draws moisture out of plant cells via osmosis. This dehydrates and desiccates the plant tissues, eventually killing the weed. Salt also changes the osmotic pressure in the root zone, making it harder for plants to absorb water and nutrients. The end result is shriveling and death.

Choosing the Most Effective Salt

When it comes to killing weeds with salt, the type of salt matters. Here are the best options

Table Salt

Regular iodized table salt contains over 95% sodium chloride, making it very effective at desiccating weeds Opt for a non-iodized product if possible, as the iodine can inhibit seed germination in areas you want to grow plants later

Rock Salt

True rock salt is halite or sodium chloride that comes directly from underground deposits. It contains zero additives, giving it excellent herbicidal properties. The jagged texture also helps it penetrate the soil.

Solar Salt

Solar salt is sea salt harvested by evaporation of seawater It has a high sodium chloride content between 92-99% and makes a fast-acting natural weed killer.

Epsom Salts

While Epsom salts (magnesium sulfate) can be used as fertilizer, their low sodium chloride content makes them ineffective against weeds.

Sea Salt

Sea salt is harvested by evaporating ocean water. With a sodium chloride content of around 80-85%, it will kill weeds, but much slower than regular table, rock or solar salt.

Road Salt

Road salt is calcium chloride, not sodium chloride, so avoid using it as a herbicide. It will not dry out and kill weeds.

Using Salt Safely to Kill Weeds

The key with salting weeds is applying the right amount in the proper way. Follow these tips:

• Always use regular table, rock or solar salt, not Epsom or sea salt.

• Mix 1 part salt with 3 parts water for maximum effectiveness.

• Add a few drops of dish soap to help the salt solution stick to leaves.

• Carefully spray or sprinkle the salt solution only on the weeds, not on desired plants. Salt can kill any vegetation.

• Apply on a dry, sunny day to allow the solution to absorb and dry out the plants.

• Expect to see results in 7-10 days as the weeds shrivel and turn brown.

• Avoid heavy salting that can sterilize the soil for years. Use sparingly.

• Salt can damage concrete and metal, so sweep up any excess.

• Consider booster applications if the weeds are large and healthy.

• Test salt on a small area first to determine efficacy and prevent overuse.

8 Best Salts for Weed Control

Looking for a top-rated salt for obliterating weeds in your landscape? Here are some smart choices:

1. Morton Salt Iodized Table Salt

With its fine grains and 99.9% sodium chloride content, Morton table salt quickly penetrates into cells and desiccates stubborn weeds. The 26 oz container dissolves easily in water for spraying.

2. Cargill Solar Salt

These dry coarse solar salt crystals are over 99% sodium chloride and highly effective at killing weeds, either dry-spread or in solution. The 50 lb bag covers a large area.

3. Scotts Epsom Salt

Despite the name, Scotts Epsom Salt contains zero sodium chloride, so avoid this product for weed control. It makes a great fertilizer and soil amendment though!

4. Snow Joe Pellet Salt

This rock salt has large pellets, allowing excellent soil penetration. With no additives, it kills weeds quickly. The 50 lb bag lasts ages. Just watch out for bulk spread near plants.

5. Cargill Rock Salt

With jagged crystals containing 98% sodium chloride, Cargill rock salt is an organic herbicide that quickly penetrates soil and kills weeds through osmotic pressure.

6. Tabor Road Salt

Since Tabor road salt is calcium chloride, not sodium chloride, it makes a poor weed killer. Use it only for de-icing walkways in winter, not the garden.

7. Accent Sea Salt

Though fine-grained, Accent Sea Salt has only 85% sodium chloride, so it works far slower than regular salt against weeds. Use higher concentrations and reapply often.

8. Dave’s Naturals Epsom Salt

Epsom salt contains zero sodium chloride. This magnesium sulfate product from Dave’s Naturals makes an ineffective weed killer but great bath soak!

The Benefits of Using Salt for Weed Control

Salt offers some advantages over other weed killers:

• Fast acting, usually killing weeds in 7-10 days

• Inexpensive and readily available

• Provides long-term weed prevention as it builds up in soil

• Easy application with spray bottles or spreaders

• Doesn’t require protective gear like some commercial herbicides

However, there are also downsides to keep in mind:

• Non-selective, killing all plants it touches

• Can sterilize soil for years if over-applied

• May leach into groundwater from excessive use

• Corrodes concrete, metals and tiles with runoff

• Needs reapplying if heavy rains dissolve it

So weigh the pros and cons before using salt for your weeding needs. And remember, only apply salt directly on weeds, never on plants you want to keep!

Alternative Natural Weed Killers

If you’re looking for non-chemical weed control options other than salt, consider:

Boiling Water

Pouring 212°F water on weeds destroys plant tissue, effectively killing weed roots. Avoid boiling water around wanted plants.

Vinegar

Spray full-strength white vinegar on weeds to burn leaves. Reapply weekly as needed. Vinegar may also harm valued plants.

Corn Gluten Meal

This organic fertilizer inhibits root formation and seed germination. Apply in spring before weeds emerge. Takes 1-2 months to work.

Landscape Fabric

Blocks light and smothers weeds. Use fabric below mulch and cut holes for desired plants. Keep fabric edges buried.

Newspaper or Cardboard

Sheet mulching with 3-5 layers of newspaper or cardboard covered with mulch kills underlying weeds by blocking light.

Manual Removal

Hand pulling and hoeing are time-consuming but cheap. Use tools correctly to remove entire weed roots.

An integrated approach using several methods usually works best for sustainable weed management without herbicides.

Timing Salt Applications for Maximum Effectiveness

For best results, apply salt weed killer when:

• Weeds are young and actively growing. Mature weeds with deep roots resist salt damage.

• No rain is forecast for 24-48 hours. This allows the salt solution time to dry and crystallize on the plants.

• Daytime temperatures are warm, over 60°F. Warm weather enhances drying.

• For annual weeds, in spring and early summer when they sprout.

• For perennial weeds, in fall when the plants send nutrients to their roots.

Avoid salting weeds during cold, wet weather when the solution will quickly wash off and dissolve. Repeat applications are likely needed with suboptimal conditions.

Safety Precautions When Using Salt as a Herbicide

Although an all-natural product, salt can still pose risks if used carelessly as a weed killer:

• Wear gloves, long sleeves, and eye protection when handling and applying salt weed spray.

• Keep children and pets away from salt-treated areas until the solution dries.

• Avoid excessive buildup of salt in soil by using sparingly and only on actively growing weeds.

• Sweep up any granular salt that lands on sidewalks, driveways, or other concrete and dispose of it.

• Prevent salt runoff into nearby storm drains, streams, or other bodies of water.

• Clean up any salt spills immediately to avoid damage to concrete or metal fixtures. Avoid salt contact with lawn furniture.

• Consult local ordinances regarding herbicide use before salting weeds. Limitations may exist in certain areas.

Exercising responsible caution allows you to harness the weed-killing power of salt safely.

Troubleshooting Salt Application Issues

Problem: The salt solution didn’t fully kill the weeds.

• Cause: Weeds too mature and developed deep roots. Salt only reaches surface cells.
• Solution: Apply early when weeds are young and shallowly rooted for best effect.

Problem: The salt seemed to disappear and didn’t kill weeds.

• Cause: Heavy rains dissolved and washed away the salt soon after application.
• Solution: Reapply salt when dry conditions resume. Avoid applying right before storms.

Problem: Salt damaged my lawn and garden plants.

• Cause: Salt makes a non-selective herbicide, killing any plant it touches.
• Solution: Use a shield and carefully target only the weeds. Rinse valued plants with fresh water if salt contacts them.

Problem: White salt residues are left on the driveway and patio.

• Cause: Excess salt was applied and was not swept up.
• Solution: Use the minimum amount needed and sweep immediately after application.

Killing weeds with salt is an effective organic alternative to commercial weed killers, with table salt delivering the fastest weed control. Use sodium chloride-based salts like rock and solar salts for best effect. Proper application technique and timing are key to maximizing results while minimizing drawbacks like soil salinization. Exercising caution and restraint allows you to harness the herbicidal power of salt for weed management the natural way. Give it a try in your garden!

Links