Adjust soil pH with lime or sulfur

Apply garden lime (calcium carbonate) to raise pH in acidic soil, or elemental sulfur to lower pH in alkaline soil. Most vegetables thrive at pH 6.0-7.0. Apply at the rate recommended by a soil test and work into the top several inches.

Why It Works

Soil pH controls nutrient availability. Even when nutrients are present, plants cannot absorb them efficiently at the wrong pH. Iron, manganese, and zinc become unavailable in alkaline soil; phosphorus and calcium become limited in very acidic soil. Correcting pH unlocks nutrients already in the ground.

Tips

• Always test pH before amending -- adding lime or sulfur without knowing your current pH can worsen the problem
• Dolomitic lime adds magnesium alongside calcium; calcitic lime adds only calcium
• pH changes take 2-3 months to fully develop, so amend in fall for spring planting
• Wood ash raises pH and adds potassium but is difficult to dose precisely