How to Raise the pH of Soil With Wood Ash

Over-acidic soil in the garden can negatively impact plant health. If the soil has already been tested and the pH is too low, the soil can be made less acidic by adding wood ashes from a fireplace. It's important to be careful, though -- raise the pH too much and you'll have an entirely different problem. If the pH of the soil is 7 or above, it's best not to use wood ash as fertilizer for the garden.

Wood ash
Face protection & gloves
Sieve

Instructions

- 1
  Determine how much wood ash can be safely applied on a yearly basis. The University of Connecticut recommends 20 lbs. per 1,000 square feet, roughly equivalent to a 5-gallon pail. For areas less than that, multiply or divide to get a rough idea how much is needed. If the garden is 10 square feet, for example, 10 divided by 1,000 is 0.01. Multiplying 20 lbs. by this figure gives 0.2 lbs. wood ash for the garden area.
- 2
  Apply ashes before the planting season, preferably in the winter. Do not apply wood ash to patches containing germinating seeds -- they could be harmed -- and do not apply ashes during rain or just before a rainstorm.
- 3
  Put on gloves and face protection to avoid breathing in too much of the ashes. If desired, the ashes can be poured through a sieve into a bucket to remove large pieces of debris.
- 4
  Scatter the ash lightly onto moist soil. Work it in with a small garden fork or trowel. Rake the area lightly afterward.
- 5
  Rinse any plants that have ashes on their leaves; the plant could suffer chemical burns if the ashes are allowed to remain on the leaves.

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