Agricultural lime: how much, and when
Farm lime 50–150 kg/mu (about 750–2250 kg/ha), split, sandy soils low. No builder’s lime.
- You already decided to lime.
- Now: which lime, how much, when.
- Read the bag.
- Agricultural lime has a calcium-oxide number; building lime is dirty and burns seedlings.
- Gypsum lifts alkali, not acid. White powder is not one medicine.
- No quicklime on seedlings; no builder’s lime as farm lime; no mix with urea the same day.
- Agricultural lime (grain land, pH below 5.5): Commonly 50–150 kg per mu, twice. Sand: the lower end. Clay: a little more. Rates follow a soil test and the local agronomist. Better too little than too much
- Name what you see before you feed.
- If leaves, roots and the surface disagree, stop.
What you see in the field
Open this page only after you have decided to amend acid soil. Read the bag: agricultural lime can go on the field; builder’s lime and leftover renovation lime cannot. Match texture: sandy soils take the low end, clay a little more, both split and worked in. Not the same day as urea or fresh manure. Grain land is commonly 50–150 kg/mu (about 750–2250 kg/ha). Do not push tea to neutral with this recipe.
Tap to enlarge. The caption says what to photograph. Missing field photos are marked as to-be-added.
Why it looks like this
Lime neutralises hydrogen and precipitates aluminium so a white tip can grow. Too much at once makes the surface too alkaline and locks micronutrients, so seedlings yellow. Split the dressing; sandy soils take the low end. The same day as urea loses ammonia and injures roots. Builder’s lime does not belong on a field.
A sketch. Do not fertilise from the picture alone.Easy to mix up
Looks like “Builder’s lime”
Builder’s lime does not belong on a field. Agricultural lime is on the label. The wrong bag injures seedlings.
Looks like “Gypsum for alkali”
Gypsum is often for sodic alkali. This page is agricultural lime for acid soil, not a white-crust reflex.
Do this / don’t do that
- 1Confirm this field needs acid amendment: grain-land pH below about 5.5 and root tips that match. Do not push tea to neutral with the grain recipe.
- 2Use only agricultural lime, never builder’s lime. Grain land is commonly 50–150 kg/mu (about 750–2250 kg/ha), sandy soils at the low end, split and worked in. Not the same day as urea.
- 3Retest pH next season. Stop once you are in range. Greenhouses take the low end.
Don’t do this first
- Do not use builder’s lime. Impurities and the alkalinity do not belong on farmland.
- Do not spread lime the same day as urea. Ammonia will escape and the root can burn.
- Do not push a tea garden to neutral as if it were grain land.
Rate range
Agricultural lime (grain land, pH below 5.5)
Commonly 50–150 kg per mu, twice. Sand: the lower end. Clay: a little more
Rates follow a soil test and the local agronomist. Better too little than too much.
Dolomite
Near the lime rate, and it brings magnesium
On dry land, when magnesium is short, this comes first.
These are ranges. Confirm with your local extension station and the product label.
One number example
Grain land at pH 5.2, sandy loam: about 50 kg/mu agricultural lime worked in, a week away from urea, retest next season. Clay at the same 5.2 can see the 150 kg/mu end of the range, still split. Do not copy that onto tea.
When you see You already decided to lime. Now: which lime, test. Write the field and the date on the bag.
Lesson video
2026-03-18 · Li Zeyu · For learning. Serious damage: local agronomist or a soil test.
For learning only. Fertiliser and pesticide decisions need a local agronomist and a soil test.
Not sure? Photograph the field to identify the problem