Idaho's land-grant extension publishes a method — not a one-size-fits-all rate. Live calculator uses this state's published method and citation. Enter the required soil-test values in the free calculator for tons of CaCO₃-equivalent per acre, ECCE-adjusted, with the citation.
Northern Idaho uses Modified Mehlich / SMP / Sikora and DOES need lime. Southern Idaho has calcareous soils and rarely needs lime.
Published source: University of Idaho — Northern ID (dryland Palouse) + Southern ID (irrigated Snake River Plain) Fertilizer Guides
It depends on the inputs Idaho's land-grant method publishes — not a single national number. Enter your values in the free Zone Forge lime calculator for tons of CaCO3-equivalent per acre, with the citation.
Source: University of Idaho — Northern ID (dryland Palouse) + Southern ID (irrigated Snake River Plain) Fertilizer Guides.
Zone Forge computes Idaho lime from that state's published land-grant method (the lab values required by this state's published method) — lime calculator, soil-test fertilizer, and full variable-rate prescriptions. See the science →