๐ŸงชSoil pH Amendment Calculator
sq ft
from a soil test

Amendment Recommendation

Amendment to addโ€”
Amendment typeโ€”
pH change neededโ€”
Application rateโ€”

Related Calculators

Understanding Soil pH

Soil pH is a measure of acidity or alkalinity on a scale of 0โ€“14. A pH of 7 is neutral; below 7 is acidic, above 7 is alkaline. Most vegetables grow best between 6.0 and 7.0.

Why pH matters

pH affects nutrient availability. Even if nutrients are present in the soil, plants can't absorb them if the pH is too far off. An incorrect pH is often the hidden cause of yellowing leaves and poor growth.

Optimal pH by crop

CropIdeal pH
Most vegetables6.0โ€“7.0
Tomatoes6.0โ€“6.8
Potatoes5.0โ€“6.0
Blueberries4.5โ€“5.5
Brassicas (broccoli, cabbage)6.0โ€“7.5
Onions, garlic6.0โ€“7.0
Beans6.0โ€“7.0
Strawberries5.5โ€“6.5

Raising vs. lowering pH

To raise pH (make less acidic): Add garden lime (calcium carbonate). Takes 3โ€“6 months to fully react. Best applied in fall.

To lower pH (make more acidic): Add elemental sulfur. Slow-acting โ€” takes several months. Or use acidifying fertilizers like ammonium sulfate for faster results.

Test first, amend second: Always do a soil test before adding amendments. Soil testing kits cost $10โ€“20 at garden centers, or send a sample to your local extension service for a detailed analysis.