To know how much lime or sulfur to add, you need your lab's recommendation from a test of your soil
To know how much lime or sulfur to add, you need your lab's recommendation from a test of your soil. We can say which way to go, but the amount has to come from the lab.
As recorded: A lime or sulfur RATE is the lab's to give, from its test of your own soil; a lime rate comes from a lime requirement test, by a buffer pH or by your pH and your soil's texture. Which way to move the pH we can say; the amount we cannot, and it is never ours.
Promising A person has checked it against its sources. How much lime or sulfur it takes depends on your own soil, so the amount is the lab’s to give from a test of it. The planner tells you which way your pH should move, and never an amount.
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. If your report prints a lime or sulfur rate, it is a real one for your ground, whichever lime requirement method your lab used, so use that. If it does not, ask your lab for its lime or sulfur recommendation; for lime, that comes from a lime requirement test, usually part of a routine soil test. Which direction to go we can tell you. Lime raises pH and sulfur lowers it.
The evidence
Evidence: checked against 2 sources in the research-based literature.
The 2 sources
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.
Lime requirement is also commonly determined by soil pH measurement and soil texture classification.
Plus one working note on how the sources were read. Every note is in the data download.
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How this rule has changed
Every change is dated, newest first. The full record, with each reason, is in the data download.
- Details updated
- Advice on what to do added
- Details updated
- Advice on what to do added
- Details updated
- Wording made clearer
- Wording made clearer
- Wording made clearer
- Advice on what to do added
- A person read the sources and confirmed it
- Added to the rules
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Milpa Gardens. “To know how much lime or sulfur to add, you need your lab's recommendation from a test of your soil. We can say which way to go, but the amount has to come from the lab.” Evidence grade: Promising. https://milpa.garden/rules/lime-sulfur-rate-lab-s-give-from/
A garden planner built on graded evidence. Every claim states its evidence grade and links its sources on the page. Cite it with the grade, and add the date you read it.
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How we grade evidence
- Well established
- The rule names its mechanism and is settled, by sources a person has read and checked or by plain arithmetic and geometry.
- Promising
- The mechanism is named and the literature backs it. A few questions are still open.
- A good hunch
- Plausible by its mechanism, but field studies are thin, so treat it as a lean.
- Contested
- The evidence points both ways, or no study has tested it, so the planner does not enforce it.
- Refuted
- The claim did not survive its sources. It is kept so the folklore can be answered.