| MARL | Calcareous clay; often used as a fertiliser (4) |
| BALLPIT | Place where calcareous clay is dug (4-3) |
| MARLPIT | Place where calcareous clay is dug (4-3) |
| LIME | It can be used as a fertiliser for fruit (4) |
| UREA | Human waste product used as a fertiliser (4) |
| KELP | Brown iodine-rich seaweed used as a fertiliser (4) |
| BONEMEAL | A coarse powder mixing animal parts and slaughterhouse products used as a fertiliser (4,4) |
| COMPOST | Organic matter used as a fertiliser (7) |
| GUANO | Seabird and bat excrement once widely used as a fertiliser (5) |
| POTASH | Alkaline potassium compound commonly used as a fertiliser, originally obtained from the residue of burned wood (6) |
| SLAG | Basically a fertiliser (4) |
| SEASHELL | Studied or collected in conchology, a calcareous exoskeleton such as the conch used as a trumpet, cowry formerly used as money, or puka for jewellery (8) |
| PHOSPHATE | Acid salt used, eg, as a fertiliser |
| COMPOSTS | Uses decayed organic material as a fertiliser (8) |
| SHELL | With types used as money or jewellery and studied in conchology, the calcareous exoskeleton of a conch, cowrie, triton, scallop or oyster (5) |
| CORAL | Calcareous deposit in the sea or in a bit of a state(5) |
| GLOBIGERINA | Marine micro-organism with a calcareous shell of chambers in a spiral (11) |
| MOLLUSKS | Invertebrates with calcareous shells, as snails and clams |
| PORTLANDSTONE | Yellowish-white calcareous material used in building (8,5) |
| CACAO | Rules out calcareous origins of chocolate tree (5) |
