Wood Ash as Fertilizer: Benefits, pH Risks, and Critical Safety Rules

Cedar ash supplies potassium, lime, and trace minerals—but its high pH makes it risky for alkaline Texas soils.

Nutrient Value

• Potassium (K), calcium (lime), magnesium, trace elements.
• No nitrogen or phosphorus—must supplement.

Application Limits

• Max 10–15 lbs/1,000 sq ft lawn (1–1.5 lbs/100 sq ft beds).
• Do not use if soil pH > 7.0 or potassium is already high.

Critical Safety Rule

Never mix wood ash with synthetic nitrogen fertilizers (ammonium nitrate, urea, ammonium sulfate). Combination produces toxic ammonia gas. Separate applications by 2–3 months.

Personal Protection

• Wear goggles, gloves, dust mask—ash is strongly alkaline (like bleach).

Alternative: Compost Addition

Thin layers between compost piles neutralize acidity and add nutrients safely.