Soil amendment calculator - compost, lime, sulfur, sand

Enter your bed dimensions and what you're trying to fix. Get the right amount of compost, lime (raise pH), sulfur (lower pH), or coarse sand (open up clay). Rates from Cornell, Penn State, and Clemson HGIC.

Bed dimensions

Length (ft)

Width (ft)

Tilling depth (in)

What are you trying to fix? Current soil pH (if you know it from a test)

Why amendment rates matter

The wrong amount of amendment can be worse than none. Too much lime in already-neutral soil pushes pH alkaline and locks up iron and other micronutrients - the chlorosis (yellowing leaves) you're trying to fix gets worse. Too much fresh manure burns roots. Sand mixed into clay without enough organic matter creates concrete.

Per Cornell Cooperative Extension's liming guide, applying lime without a soil test is the most common amendment mistake in home gardening. Get a soil test through your county Extension ($10-25) before applying any pH-changing amendment.

Per Clemson HGIC, lime takes 6-12 months to fully change pH. Sulfur takes 3-6 months. Apply in fall for results by spring.