You can use Comfrey for practically anything! Here are some ideas.
Comfrey concentrate as a plant feed. Cut the leaves of the plant just prior to flowering and place in a barrel with a hole in the bottom. Weigh the comfrey leaves down to crush out the juice. After a couple of weeks a dark juice will seep from the hole. It is important to minimise evaporation of the effluent while it is being collected. Dilute the effluent 25:1 with water and use as a plant feed, either foliar or direct into the soil.
You can also produce comfrey tea as a plant feed by placing leaves in a barrel full of water (say a barrow full in a 40 gallon drum). After a couple of weeks the liquid will be ready to water straight onto the plants that need feeding. This method is pretty smelly, and if you have difficult neighbours it may be best to stick to the concentrate method!
A simple way of using the leaves to feed plants is to mulch. A layer of leaves around tomato plants will soon rot down proving the nutrients and minerals that comfrey is famed for, as well as protecting the soil surface from sunlight and minimising evaporation. A comfrey mulch is extremely pleasing to the eye and represents a holistic way of growing veg that is looking after the soil, its water, micro organisms, and tendency to erode if unprotected, as well as the crop.
Comfrey can also be used as an animal feed particularly for pigs and poultry. According to the late guru of Comfrey, Lawrence Hills (Founder of Garden Organic), the comfrey fed ad lib to pigs will replace half their feed requirements. This represents a considerable saving. Similarly with hens he states ‘ a feeding system was tried by Mr E V Stephenson with his laying battery, feeding 2.5 to 3 ounces a head of wilted comfrey per day, with no fall in egg yield , and a saving in concentrates amounting to an ounce a day per bird. As with pigs comfrey is wilted before feeding so that the spikes on the leaves and stems loose their stiffness.
Medicinal uses. Comfrey is most famous for beating into a cataplast! This is a poultice of mashed leaves that is wrapped around a swelling or sprain to ease inflammation. In the Middle Ages it was a famous remedy for broken bones. The name Comfrey is a corruption of con firma, in allusion to the uniting of bones it was thought to effect. The roots can be grated into a paste and covered with boiling water to produce an ointment for sprains and bruises. See a qualified herbalist before using comfrey medicinally.