How to Use Wood Ashes in the Home and Garden | The Old Farmer's Almanac

How to Use Wood Ashes in the Home and Garden


5 Practical Uses for Wood Ash

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If you burn firewood, you have wood ashes. Don’t throw them out! There are many surprising ways to use ashes around the garden and home. Here are five practical ideas.

Each cord of firewood that you burn will leave you with about 20 pounds of ashes or more, depending on your fuel source, heating appliance, and wood-burning skill.

Instead of putting them out with the trash, put your ashes to use in and around your garden and home!

1. Amending Lawn and Garden Soil

Wood ash is a readily available source of potassium, calcium, and magnesium which are essential for plant health. It’s a common way to increase your soil pH.

However, it is very important to know when to use wood ash and when NOT to use wood ash.

The answer to that question comes down to:  What is your soil pH? Get a free soil test. (See how to take a soil test.) Soils in the pH range of 6.0 to 7.0 is optimal for most lawns and garden plants. Note: Select plants prefer a soil with a lower pH (acidic) and certain plants grow better in soil with a higher pH (alkaline).

When to Add Wood Ash:

  • Add if your soil PH is too low (falling below 6.5). Magnesium and calcium availability are reduced. Just as an example: Tomato blossom end rot is caused by lack of available calcium in the soil. 

When NOT to Add Wood Ash:

  • Do not add wood ash if your soil is already alkaline with a pH greater than 7.0. In a soil that is already alkaline, you will hurt your plants and even kill them. Many plants can not take up nutrients if the soil pH gets too high. As an example: trees will have yellow leaves (chlorosis); some vegetables and fruit trees will also suffer. Elemental sulfur is used to lower soil pH. 
  • If your soil is already in the optimal range (6.0 to 7.0), you do not want to mess with the pH.
  • Don’t apply ashes around acid-loving plants such as blueberries, rhododendronsazaleas, and holly, since wood ash will raise the pH and make the soil less desirable to those plant. 

How to Use Wood Ash in the Garden

Wood ash is similar to lime (which is ground limestone or calcium carbonate) which also increases soil pH. However, unlike limestone, which can take 6 months or more to change soil pH, wood ash is water-soluble and changes the soil pH rapidly. Apply roughly twice as much ash by weight as the recommendation for limestone.

Soils already in the optimal pH range of 6.0 to 7.0 can handle 20 pounds, or one 5-gallon pail of hardwood ashes per 1,000 square feet annually without raising the pH unduly. Do not apply more than 20 pounds as high rates or wood ashes may cause short-term salt injury. Be careful when adding wood ash to your garden.

Wear eye protection, gloves, and a dust mask and broadcast the ashes evenly on a dry, windless day. Mix them into the soil thoroughly before planting. Hose off any ashes that settle on actively growing plants to prevent burning the foliage.

Watch Video Demo to see how to apply wood ashes to the garden.

More Ways to Use Wood Ash

Our ancestors learned to make lye, a caustic cleaning agent, at least 5,000 years ago by running water through wood ash, eventually learning to combine it with animal fats and water to make soap. Early Americans used ashes or homemade lye water for scrubbing wood floors, laundering clothes and bed linens, and soaking fresh-killed hogs to help remove the hair. For centuries, potters and ceramicists have used wood ashes to create beautiful glazes. Take a look

Here are a few more suggestions for modern use:

2. Repel Slugs

Sprinkled lightly around susceptible plants, wood ashes will irritate slugs’ moist bodies and repel them. The repellent effect will disappear after rain or irrigation dissolves the ashes. See other ways to deter slugs.

3. Melt Ice and Provide Winter Traction

Spread on walks and driveways, wood ashes will melt ice and provide traction. They don’t work quite as well as salt, and they can be messy if you don’t take steps to prevent the ashes from getting tracked into the house. But they’re free, and they won’t damage animal paws or paved surfaces. 

4. Reduce or Remove Oil Stains

As a desiccant, wood ashes are very good at pulling liquids from other materials, including hard-to-clean surfaces such as asphalt, stone, and cement. Simply sprinkle wood ashes on the stain and they will absorb any surface liquids. For tougher stains, sprinkle on wood ashes and then use an old rag to scrub the stain.

5. Clean Glass and Metal 

Hard to believe, but hardwood ashes make fast work of grease, grime, and tarnish on glass, silverware, ovenware, grills, and glass stovetops, as well as gummy residues left by stickers and labels. 

Dip a damp cloth in wood ashes or make a thick paste of ashes and a little water, scrub lightly with a cotton cloth, and rinse away with plain water and another cloth. Wear gloves for these scrubbing tasks to avoid caustic burns.

Be Safe! 

As with all aspects of wood heating, use vigilance and common sense in handling and managing the ashes. Store them in a covered metal container set on dirt or concrete a few feet in all directions from any combustible surface.

Even though the ashes may appear cold, buried embers may remain live for days, even weeks.

Do you know any other uses for wood ashes? Let us know in the comments!

2023 Almanac Club