Trifolium incarnatum. Hardy Annual. Whenever you choose to sow crimson clover cover crop seeds, it will flower in April, and that’s the time to till it under or pull it out. As it sets seed, the stems become fibrous and tougher to break down. This plant is particularly succulent and is easily tilled or hoed under. You can remove the tops to the compost, or simply turn the whole plants under. They will be broken down in about ten days, and the soil will be ready for planting nitrogen-loving crops. Plant between late March and early October. Hardy to Zone 6: -23°C (-10°F). 500g covers approximately 179 m2 (1,925 ft²).