How to find out your soil type
Step-by-step jar test, a table of sand, silt and clay percentages, a calculator and the vinegar test for chalky soil.
- Fill a glass jar one-third full with soil from 10–15 cm deep, without stones or roots.
- Add water to three-quarters and a teaspoon of washing-up liquid or salt to separate the particles.
- Shake hard for 3 minutes, then leave the jar still.
- After 1 minute, mark the bottom layer: sand. After 2 hours, mark the next: silt. After 24–48 h, when the water is clear, mark the top layer: clay.
- Measure each layer in centimetres and enter it below: we work out the percentages.
Reference table (% of total layers)
| Type | Sand | Silt | Clay |
|---|---|---|---|
| Sandy Gritty, won't form a ball | >70% | <20% | <15% |
| Loam Forms a ball that crumbles | 30–50% | 30–50% | 10–25% |
| Silty Smooth, like flour | <30% | >50% | <25% |
| Clay Sticky, rolls into a sausage | <45% | <40% | >35% |
Is it chalky? Drip vinegar on dry soil: if it fizzes, your soil is chalky (high pH). Choose “Chalky” whatever the texture.
Your layers in centimetres
Enter the height of all three layers.
Soil type
- SandyDrains fast and loses nutrients: add compost every autumn and water little and often.
- LoamThe ideal soil: keep it fertile with compost and crop rotation.
- SiltyFertile but crusts when dry: mulch it and don't walk on it wet.
- ClayHolds water and compacts: never dig it wet and improve structure with organic matter.
- ChalkyHigh pH: citrus may yellow (chlorosis). Apply iron chelate in spring.
