What to Do with Wood Ash from Woodstoves and Fireplaces
From one of my Permaculture Consultation clients
Dear Cathe’,
It was great to visit with you yesterday. I have a question. We have been collecting ashes from Kathleen’s fireplace in a large trashcan in the garage. I was wondering about using them in the greenhouse or garden. Do you know of any uses for wood ash? What do you think about putting ash in the compost?
Love, Katherine
Hi, Katherine,
Take wood ash from wood stove or fireplace in a metal bucket. Never store in plastic until ash is absolutely cool. This way you avoid burning down buildings.
Use only high quality wood ash. No ashes from BBQ grills, cardboard, plywood, painted, or pressure treated wood. Hardwood ash (oak) is superior to soft wood (pine) ash.
Three Caveats
1. DO NOT USE ASH IF YOUR SOIL HAS AN ALKALINE pH of 7.5 or higher. It will make the soil too alkaline or salty. Alkaline soils are found in low rainfall areas in the West. Use wood ash only in locations where soils are acidic, like forest soils and mountain soils, or places where there is adequate rainfall in the warm season .…not in alkaline soils like the desert. If in doubt, contact your local Master Gardeners http://www.ahs.org/master_gardeners/
If you have been farming or gardening with chemicals, check your soil pH. Most chemicals increase the pH and will eventually salt the soil
On the pH scale, 7 is neutral like pure water, below 7 is acidic with 1 being the most acidic like battery acid; and above 7 is alkaline with 14 being the most alkaline like liquid drain cleaner. Normal garden soil is typically 5.5 to 7.5 pH. Wood ash is typically 10.4 pH
2. Don’t use wood ash near these and other acid lovers: azaleas, rhododendrons, blueberries, mums, marigolds, mountain laurel, oak, pecan, and sweet potato
pla 3. Sprinkle wood ash before plants emerge, in winter or very early spring. Don’t plant seeds or seedlings until at least two weeks after ash has been applied, or wait until new plants are a few weeks old to spread it. The smaller they are, the more dramatically plants may react to the sudden increase in pH.
Wood ash has the same composition as limestone. Use it where you would use lime. If you put a pile of wood ash outside, and it rains, it will turn to limestone.
The secret to using wood ash is to SPRINKLE IT or DUST IT.
Use wood ashes to:
1. Spread finely on the soil on your property. Use a large coffee can or a box with nail holes punched into the bottom. Spread so it looks like fine baby powder on the soil.
2. Enrich compost. Enhance compost nutrients by sprinkling in a few ashes so it looks like a fine powder. Adding too much, though, ruins compost.
3. Composting citrus rinds. In a bucket of wood ash, place rinds of citrus or anything that is hard to breakdown. Make sure to cover the bucket.
4. Calcium loving plants. For calcium-loving plants like tomatoes, sprinkle and spread out ¼ to 1/8 cup (NOT MORE) right in the hole when planting. More is not better. It should look like a powdered baby’s butt.
5. Block garden pests. Spread evenly around garden beds, ash repels slugs and snails.
6. Control pond algae. One tablespoon per 1,000 gallons adds enough potassium to strengthen other aquatic plants that compete with algae, slowing its growth.
7. De-skunk pets. A handful rubbed on your dog’s coat neutralizes that familiar lingering odor.
8. Hide stains on paving. This Old House technical editor Mark Powers absorbs wet paint spatters on cement by sprinkling ash directly on the spot; it blends in with a scuff of his boot,
9. Clean glass fireplace doors. A damp sponge dipped in the dust scrubs away sooty residue.
10. Make soap. Soaking ashes in water makes lye, which can be mixed with animal fat and then boiled to produce soap. Salt makes it harden as it cools.
11. Shine silver. A paste of ash and water makes a nontoxic metal polisher.
12. Kill moss in the lawn. Sprinkle lightly over lawns that have moss problems.
13. Toothpaste. In the old days before tooth paste, ash was used to clean teeth. The potential bio-hazards in the modern world are the chemicals used in fire starters, newsprint, and magazine inks. Using baking soda instead tastes much better and is a common practice.
14. Cleaning white boards. Ashes are good for cleaning white boards that have been marked by grease pencil or marker. It even works on permanent marker that has been mis-applied to a white board.
15. Melt ice. My personal all time favorite. Keep container of ashes in car (or on the porch for sidewalks) in the icy season to add traction and de-ice without hurting soil or concrete underneath. In Alaska, we carried a shoe box of fine screened ash to get vehicles out of ice. Sprinkle handful of ashes out about a foot in front of the tires that have power (4 wheel drive ‑all tires; front wheel drive ‑front tires; rear wheel drive- rear tires). Drive right out of trouble as if you were on dry pavement. Eliminates the use of salt for icy sidewalks.
Check out the composition of elements in wood ash, below, from the University of Georgia.
Hope this gives you some ideas for what to do with all that wood ash from our unusually long and cold winter,
Cathe’
Composition of Elements in Wood Ash Mean and (Range) taken from analysis of 37 ash samples
Macro elements in average %, range of 37 samples, highest %
Calcium 15 (2.5–33) 31 Potassium 2.6 (0.1–13) 0.13 Aluminum 1.6 (0.5–3.2) 0.25 Magnesium 1.0 (0.1–2.5) 5.1 Iron 0.84 (0.2–2.1) 0.29 Phosphorus 0.53 (0.1–1.4) 0.06 Manganese 0.41 (0–1.3) 0.05 Sodium 0.19 (0–0.54) 0.07 Nitrogen 0.15 (0.02–0.77) 0.01
Micro elements or Trace Minerals in mg, range of 37 samples
Arsenic 6 (3–10) Boron 123 (14–290) . Cadmium 3 (0.2–26) 0.7 Chromium 57 (7–368) 6.0 Copper 70 (37–207) 10 Lead 65 (16–137) 55 Mercury 1.9 (0–5) . Molybdenum 19 (0–123) . Nickel 20 (0–63) 20 Selenium 0.9 (0–11) . Zinc 233 (35–1250) 113
Other Chemical Properties
CaCO3 Equivalent 43% (22–92%) 100% pH 10.4 (9–13.5) 9.9
% Total solids 75 (31–100) 100