April I: Comfrey Strain Bocking 14 as an organic green manure

Comfrey is a plant recommended by many organic gardeners. Why is this?

1. It grows rapidly and its leaves can be harvested 4 or 5 times a season for many years.

2. The composition of its leaves are reckoned to be almost perfect in terms of minerals for feeding plants.

3. Its leaves can be rotted to produce a concentrated tea, suitable for feeding many plants (notably beans, tomatoes and potatoes).

4. It acts as an excellent compost accelerator and enriches the quality of compost at the same time.

5. Planting potatoes wrapped in comfrey leaves can enhance crop yields.

6. Combining comfrey, grass cuttings and manure can make a perfect hilling up mixture for potatoes.

7. The deep rooting of the plants brings buried nutrients to the surface, as the remaining leaves in autumn are left to die back, creating surface compost.


Lawrence Hills of the Henry Doubleday Association pioneered research into uses of comfrey, identifying Bocking Strain 14 as an optimal strain. It is a sterile strain, which means it does not spread and invade other areas of your garden. It is also very vigorous, giving large yields each season.

If you wish to establish some comfrey, it is a good idea to do this in early to mid summer and not make any harvests until the following spring. Planting your maincrop potatoes when the first harvest of comfrey is ready is a natural way of timing potato planting to natural cycles.

For a fascinating read about Hills’ research on comfrey, read:

‘Comfrey: Past, present and future’, Lawrence D Hills (1976) ISBN 9780571110070

Author: Rhys

Rhys trained as a research biologist, working for a decade in the cancer research charity sector, before completing an MBA and working in management consultancy, technology transfer and early technology investment spaces, mostly working with UK academics to turn their scientific discoveries into value for society. AS a younger man, he was fascinated with mountains, both climbing them and ski-ing down them. Whilst living in Scotland, he completed a round of (then) all 277 Munros, the independent mountains over 3000ft originally complied as a list by Munro. He also spent his holidays representing the Ski Club of GB, as a Representative and Party Leader between 1990 and 1997. During that time, he found to his bemusement that he was able to predict, without understanding fully why, to a remarkable degree of accuracy, when good snow conditions would occur in the Alps, gaining an unworthy reputation for predictive genius in 1990 when predicting the evolution of the 1989/90 winter in Wengen, Switzerland for his CEO boss. He used this skill for the next seven years to ensure that he enjoyed powder snow pretty much every time he went ski-ing. An MD student he was training in Oxford also impressed his wife by taking Rhys' advice about when to take her to Italy in the mid 1990s! In recent years, Rhys has turned his mind toward how to grow prize tomatoes, winning several prizes in local and London shows and has, in the past 3 years, moved toward taking over a 50 square metre urban vegetable patch, which he has turned into a no-dig area since autumn 2014.

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