Comfrey is the organic gardener's best friend, offering nitrogen, phosphorus and potassium for growing plants.
Comfrey Bocking 14 plant
Garden comfrey has high nutrient content and can be cut several times in a season.

Comfrey's leaves are full of nitrogen, phosphorus and potassium - all nutrients needed by growing plants. Master the use of comfrey and you'll never need to buy expensive fertiliser again.

How to make comfrey liquid fertiliser

Follow these simple steps:

  • Cut off the leaves about 5cms above soil level. Wear gloves, as the stems are covered in stiff hairs that can irritate the skin.
  • Fill a bucket or barrel with water and add approx 1kg of cut or bruised leaves to every 15litres of water. You needn’t be too precise!
  • Press the leaves down firmly so they are covered with water, and cover the container.
  • After four to six weeks a noxious (very) smelly brown liquid is ready for use. There is no need to dilute.
  • Strain off the sludge at the bottom, and put it on the compost heap.

To make a concentrate, you don’t need water:

You will need:

A 2-litre plastic drinks bottle, without a cap

A collecting vessel – large yoghurt pot, ice cream carton or similar

  1. Turn the bottle upside down and cut off the bottom.
  2. Pack in the cut and bruised comfrey leaves so the bottle is full. Press them down firmly.
  3. Cover the open end with a polythene bag, held in place with an elastic band, to prevent drying out.
  4. Stand/fix/wedge the bottle upside down so that it will drip into your collecting vessel.
  5. As the leaves rot, a brown comfrey liquid will drip out of the bottle into the collecting vessel below.
  6. Add fresh cut/bruised leaves, pressed down firmly, into the bottle, to keep a constant supply of rotting material
  7. This concentrate should be watered down according to its strength – when thick and black, dilute 1 part feed to 20 parts water; when thin and brown, dilute 1 to 10. You needn’t be too precise.

How to use your comfrey liquid fertiliser:

  1. Use as a summer feed for tomatoes, peppers and cucumbers (apply as soon as the flowers have set fruit).
  2. For hanging baskets and pot plants.
  3. For other hungry flowering plants such as clematis and dahlias.

Make your own comfrey feed with Emma 🔗

Learn more about making comfrey liquid plant food with our head gardener Emma's tutorial...

Comfrey flower

Other ways to use comfrey leaves

  • Place cut or bruised comfrey leaves in alternate layers throughout your compost heap. Their decomposition will encourage bacterial action causing the heap to heat up and speed up the composting process.
  • Use as a mulch. Chop up comfrey leaves with grass cuttings, and place a 5cm layer on the surface of the soil around all plants. This will slowly rot down to provide nutrients and act as a mulch to keep in moisture and help control weeds.
  • Add fresh cut leaves to your leafmould heap. Their nutrient-rich liquid will be absorbed, making it a perfect medium for growing seeds and potting compost.
  • Fertilise the bottom of your potato and runner bean trenches with a layer of comfrey leaves. As they break down, the plant roots will access the potassium-rich fertiliser.

You can buy comfrey plants from the Organic Gardening Catalogue here.

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