A lime or sulfur RATE requires a buffer-pH measurement. Direction is free; the amount is not, and it is the lab's to give, never ours.
Promising · suboptimal if ignored → advise
How it works
Buffering capacity, which is set by clay and organic matter, decides how much lime moves pH at all, so the same target takes very different amounts in sand and in clay.
What to do about it
We will not tell you how much lime or sulfur to add, and neither should anything that has not measured your soil's buffering capacity. If your report carries a buffer pH, the rate printed on it is a real one for your ground - use that. If it does not, ask your lab for a lime requirement test; it is usually part of a routine soil test and costs nothing extra. Which direction to go is free: lime raises pH, sulfur lowers it.
The evidence
Evidence: confirmed against 2 sources in the research-based literature.
the 2 sources
UF/IFAS Extension HS1207, Liu & Hanlon, 'Soil pH Range for Optimum Commercial Vegetable Production', edis.ifas.ufl.edu/publication/HS1207 (read 2026-07-25). The mechanism, stated outright: 'The amount of lime required to increase soil pH is determined by the size of the limestone particles being used and, most importantly, the buffering capacity of the soil.' What buffering IS: 'The buffering capacity refers to the soil's capacity to minimize change in the acidity of a solution when an acid or base is added into the solution.' What sets it: 'Buffering capacity is controlled by the soil's clay content and the amount of organic matter present.' And the consequence this rule turns into a refusal: 'Soils with large buffering capacity need more agricultural lime to adjust soil pH than those with lower buffering capacity for the same incremental change in soil pH. However, sandy soils have lower buffering capacity and need less lime for the same incremental change in pH than clay soils.' The page also names the remedy the ruling_text points at: 'The UF/IFAS Extension soil testing lab offers a Lime Requirement test as a component of a routine soil test, which provides a liming recommendation based on the buffer capacity of the soil sample.'
WHAT THE SOURCE DOES NOT SAY, and it is why this rule is promising rather than well established: it states that buffering capacity determines the amount, and it does not quantify how wrong an unbuffered estimate would be. The claim that the error is large enough to WARN a home gardener about is a judgement this corpus is making on top of the mechanism, not a sentence anyone published. Promising + suboptimal derives `advise`, which is the mildest non-inert ruling, and the ruling_text is phrased as a refusal to guess rather than as a prediction of harm.