Comfrey is a hard working herb that many organic gardeners swear by. Known technically as a ‘Dynamic accumulator’, comfrey grows a very deep tap root that can penetrate soil down to 3 metres and this enables it to draw minerals back up to its foliage. As a result, comfrey is rich in potassium, an essential nutrient for healthy strong growth in many plants – especially fast growing gross feeders such as tomatoes, zucchini and potatoes. Its leaves are first wilted and then used to line trenches before potatoes are planted, they can also be used as a mulch at the base of tomato plants. Leaves can also be thrown into the compost heap as an ‘activator’ to get things decomposing. Most commonly, comfrey is used to make a useful plant food when the leaves are rotted down into a liquid form.
Caution: The issue with comfrey is often more one of how to get rid of it in a garden rather than how to get it growing. Any of part of the root left in the soil is likely to re-grow. For this reason it is best planted in containers where it can be controlled. If planting in the ground, comfrey is usually paced beneath fruit trees in an orchard where its rampant growth is less likely to be an issue.
The ‘Bocking 14’ cultivar of Russian comfrey is recommended as it has sterile flowers and does not spread by self seeding.
Companions Tomato, capsicum, cucumber, potato
Plant root cuttings or seedlinsg in autumn or early spring countrywide.
Comfrey grows well in full sun as well as partial shade.
Comfrey will grow in most soils. Ideally it likes a richly composted slightly moist soil to feed its healthy appetite for nutrients such as nitrogen.
Root cuttings of comfrey and comfrey seedlings can be bought mail order or from some garden centres and nurseries. Alternatively, get a friend who has comfrey growing in their garden to break off a piece of root with a few leaves growing on it. Pop your cutting into prepared soil with the top of the root itself just below soil level and water in.
Water during in dry periods. Once comfrey has established and is starting to grow you shouldn’t need to continue with watering.
If you are caught short in the garden, peeing on your comfrey plants gives them a welcome boost of nitrogen.
Comfrey grows very fast and leaves will reach up to knee height. Leaves are coarse and hairy so best pick them with gloves to avoid skin irritation. For optimum nutrient content it is said that comfrey leaves are best harvested just before the flowers open. Cut all foliage down to about a thumb’s length above soil level – don’t worry, it will re-grow up to five times in a spring/summer season.
Uses for Comfrey:
Half fill bucket or barrel with comfrey leaves and then fill up with water. Cover. In 4 to 5 weeks’ time you will have a liquid comfrey mix that is garden ready.
To make a concentrate, stack leaves in an old bucket and weigh down with a brick. Make a small hole in the bottom of the container so that the black comfrey concentrate can pour out into an appropriate container. This can then be diluted for use in the garden. Add one part concentrate to 10 parts water – are dilute till liquid resembles weak tea.
NB: Rotting comfrey smells like an open drain so place any containers away from your house if possible.
When you have used up your liduids add the sludge to compost heap or dig into garden.
Comfrey leaves can be used as a mulch around plants to break down and act as a slow-release source of plant nutrients.
Comfrey leaves are added to compost heaps to stimulate the composting process.
If Comfrey gets out of control in your garden send in the chickens – they love it!
Ongoing: Remember, comfrey is difficult to remove from soil once planted so think carefully about where you grow it.