Fighting weeds with soda: does it work and is it allowed?

Fighting weeds with soda: does it work and is it allowed?

What is soda

Washing soda (sodium carbonate) is a natural salt that is closely related to and is often confused with baking soda (sodium hydrogen carbonate). Both substances are salts derived from carbonic acid.

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The difference lies in the hydrogen component, recognizable by the syllable “hydro”. The white soda powder forms a strong lye with water. It reacts much more basic than baking soda and is therefore ideal as a grease-dissolving household cleaner.

Remove moss and algae with soda

Moss likes to get stuck in the cracks in the paving stones and has to be laboriously removed with a joint scraper. Once the surface has been mechanically cleaned, you can effectively prevent re-growth with soda. You can also effectively combat algae deposits with this agent.

If the area borders on the lawn, however, the mixing ratio must not be too strong. It is enough to dissolve a level tablespoon of washing soda in a liter of water and spray the area with the solution. Let the soda soak in for at least five hours and then rinse off with the garden hose.

Soda as a weed killer

In the bed or lawn, soda should only be used with great care. Washing soda has a very strong effect and you can inadvertently burn the green you want.

  • If you want to destroy weeds in a targeted manner, the mixing ratio should never be greater than one tablespoon of powder to one liter of water.
  • Pour the solution into a spray bottle and wet the weeds.
  • Make sure there is a minimum distance of ten centimeters to other plants.

Precautions in use

Do not breathe the powder and avoid eye and skin contact. Washing soda is irritating to the respiratory tract, eyes and skin and should therefore be used carefully. Wear rubber gloves when working.

Why is soda environmentally friendly and is it allowed to be used in the garden?

When degraded, soda binds acid and water hardness. Limestone and carbonic acid are produced, and thus minerals that can also be found in drinking water. Due to the spontaneous shift in the pH value, soda lye should still only be used to a very small extent in the garden.


When it comes to killing weeds with home remedies such as vinegar and salt, you are in a gray area. There may be a fine when using it. Although there is currently no known case in which the use of soda was punished, this cannot be ruled out. It is therefore advisable to control weeds mechanically or to use herbicides from specialist shops.