Washington's land-grant extension doesn't use a one-size-fits-all number — it uses a published method. Enter your soil-test values in the free calculator and Zone Forge returns tons of CaCO₃-equivalent per acre, ECCE-adjusted, with the citation.
Eastern WA Palouse and Western WA need lime. Central WA Columbia Basin irrigated rarely does. WSU FS398E (June 2025).
Published source: WSU Extension — East/West Cascade nutrient + Inland NW lime (combined source)
It depends on your soil's buffer/acidity reading and your target pH — Washington publishes a method, not a single number. Enter your values in the free Zone Forge lime calculator for tons of CaCO3-equivalent per acre, with the citation.
Source: WSU Extension — East/West Cascade nutrient + Inland NW lime (combined source).
Zone Forge computes every Washington recommendation from that state's own published land-grant method — lime, soil-test fertilizer, and full variable-rate prescriptions. See the science →