The leaves of Comfrey (Symphytum), which can be harvested several times a season, are used as a compost activator helping the breakdown of other compost materials. Also used as a mulch, or is superb used as a liquid manure on tomato and potatoes plants. Comfrey grows in any soil, preferably moist, in sun or part shade. Height to 120cm (4ft).Sow seeds March to June in a seedbed or in pots indoors. Sow seeds thinly, 12mm (½in) deep in drills 30cm (12in) apart. Seeds can also be sown in pots or trays under glass and transplanted.Transplant when large enough to handle to 6cm (2ft) apart between plants.Keep well-watered until established. Cut leaves regularly throughout the summer and autumn.