Liming calculator

Use agricultural limestone only. Never put hydrated lime or quick lime in a pond with fish. Spread it over the whole bottom in fall or winter, or over the shallow margins if the pond is full. A bottom soil test from an extension lab is more accurate than this table. One liming lasts 3 to 5 years, so recheck alkalinity each spring.

Table rates are for pure calcium carbonate (100 percent CCE) and follow SRAC publication 4100, Liming Ponds for Aquaculture, and Mississippi State Extension publication 1428, Managing Mississippi Farm Ponds and Small Lakes. The bag or quarry sheet gives the neutralizing value of the lime you can buy, and the rate is scaled up for anything under 100 percent. Finer ground lime acts faster, so ask for material that passes a 60 mesh screen.

Below 20 ppm alkalinity, fertilizer does nothing until lime brings the alkalinity up, and the pond produces few fish. Between 20 and 50 ppm the pond grows fish without lime, so liming is only worth it if you fertilize. At 50 ppm or more the pond does not need lime.

Practitioner discussion: Pond Boss forum thread Fertilization of ponds.