Discover: Comfrey

Why can't you eat one of the most important plants grown on an organic allotment? Because it is Comfrey which is the backbone of organic gardening, but it is also inedible. Comfrey grows strongly, is easy to use and is oustandingly beneficial to the allotment, but it is not a vegetable. As a strong grower, the Comfrey roots grow deep into the soil and transfer all the nutrients and goodness into their leaves. This means that as a fertilizer it can outmatch most commercially available fertilizers in its usefulness to the allotment holder, and which is why it is so important for organic growing.

• Comfrey is a deep-rooted plant and will not do particularly well on shallow soil.
• Prefers a fertile soil, as do most plants, but is a hardy perrenial and will propogate year after year if situated well.
• Position in a sunny spot, although full sun is not essential.
• Growing comfrey in your garden should be planned well, as it will grow bigger every year.
• One of the major practical uses for the average gardener is growing comfrey as a green manure. 
• You can simply lay the harvested leaves on the ground around your vegetables to mulch or you can go all out and make your very own organic feed.
• An old gardener on our allotment site has been using this fertilizing method for many years and has had great results. 
• If you want to grow some quickly, buy some mature plants, you can propagate in the Autumn by removing the offsets from the original plant and planting spacing about 3 ft apart. 
• Plant root cuttings 2-4 inches deep depending on the size of the cutting, laying the root cutting flat in the dug hole. Water well and let it grow!!
• Buy the variety called Bocking 14, it is high in nutrients and sterile (you don’t want comfrey popping up all over the place), so Bocking 14 is exclusively propagated from root cuttings.
• Older plants become less efficient, so every 3—4 years lift and divide the clumps, planting back the only the youngest and these will be more productive. 
• The leaves appear from April to late October. 

There are several ways in which you can use this plant in the garden:

Chopped up comfrey leaves

• You can use the first cut of leaves by chopping them up and placing them in a trench with main crop potatoes. 
• As the leaves are high in potassium, they make a excellent fertilizer. 
• Allow to wilt after cutting, then layer to a depth of 2.5-5cm (1-2in). 
• Comfrey can also be used on other plants that benefit from high doses of potassium, like tomatoes and runner beans. 
• It has also been used to as a top dressing around soft fruit bushes, as they break down gently cultivate them in.

Comfrey concentrate

• To make concentrate, fill a large plastic container with cut leaves and put a lid on it. 
• Drill a hole 2cm (¾in) in diameter in the bottom of the container and place it on a stack of bricks.
• Position a wide-neck bottle under the hole. 
• After two to three weeks, dark liquid will start to trickle into the bottle.
• Store the liquid in a cool, dark place. 
• Use as dilute liquid feed, one part concentrate to 10 parts water, and give at every watering.
• Typical nutritional value is very weak, about 0.79 per cent N, 0.26 per cent P, 2 per cent K.

Composting

• Transfer the last of the plants leaves in October, together with all their goodness, into your compost heap.