Particle size analysis of the soil used to grow plants and inserted into pipes.
| Particle size | Percentage |
|---|---|
| Fine gravel (2.0 mm) | 3 |
| Fine sand (0.15 mm) | 20 |
| Very coarse sand (1.0 mm) | 6 |
| Very fine sand (0.05 mm) | 7 |
| Coarse sand (0.5 mm) | 19 |
| Silt and clay (< 0.05 mm) | 2 |
| Medium sand (0.25 mm) | 43 |