You can accumulate up to 60 pounds of wood ash by burning just one cord of wood in your fireplace or wood stove. The most valuable component in wood ash for your garden is calcium carbonate. This is the common liming material that is used to neutralize highly acidic soils. The ashes also contain small amounts of micro-nutrients which can be beneficial to many plants. Wood ash can be an effective fertilizer when used correctly and in moderation. Too much ash can also harm some plants and soils.
Slightly rake around deciduous trees, shrubs and vines. Place 1/2 inch of ash over the soil and rake to work it in. Water to release the micro-nutrients into the soil. Do not use around azaleas, rhododendrons or junipers. Acid-loving plants will react adversely to the neutralizing effect of the ashes.
Place one gallon of ashes per square yard over your garden bed in loam or clay soils. Use only a half of a gallon per square yard in sandy soils. Work into the soil prior to planting your garden. Do not use wood ash around potatoes or any acid-loving vegetables.
Top dress your lawn with 1/4 to 1/2 inch of ashes each year. Water in immediately so the ash does not blow away.
Place a ring an inch high around any plants that snails or slugs like to eat. They will go through the ash and be killed by it before they reach your plant.
Place 1/4 cup of ashes in the planting hole of tomatos or other calcium-loving plants when planting. The ashes will give them a great start.
Add one tablespoon to every 1,000 gallons of water in your pond. The ash will strengthen pond plants and slow the growth of algae.