how to Make Comfrey liquid fertiliser

FAQs about Comfrey I have answered in this article


What is Comfrey used for?    Its uses in the garden, How to make comfrey liquid fertiliser tea.
How is it good for plants?       How to grow my own comfrey plants

What is comfrey?

  • Comfrey is a member of the borage family, a strong-growing perennial with  12 to 18 inches long hairy leaves on short stems growing from a central crown.
  • It has a pretty blue bell flower that fades to pink. The plant can reach a height of over two feet with a spread up to 3 feet across.
  • The comfrey plant has medicinal uses, but my main interest right now is in its use as a plant food...........
the comfrey plant
the comfrey plant

Why is Comfrey good for making fertiliser for feeding plants?

  • Comfrey has deep roots that bring nutrients up from deep down in the ground.
  • The nutrients are stored in the leaves and are rich in nitrogen and potassium with some phosphorus as well. 
  • The leaves are also full of silica, calcium, iron, magnesium and other essential nutrients to help plants grow and stay healthy.
  • Comfrey leaves when used to make liquid fertiliser makes a really unbeatable natural slow release plant food.
  • Over-feeding plants with manufactured fast-release fertilisers causes a quick burst of unnatural growth leaving the plants vulnerable to pests and disease similar to the hit unhealthy fat people get when eating burgers and cola. Comfrey is a slow release natural food.

The benefits of feeding plants with homemade Comfrey liquid fertiliser

Over-feeding your plants with off-the-shelf fast-release fertilisers often causes just the opposite to what is intended, a quick burst of unnatural growth leaving the plants vulnerable to pests and disease. Similar to the hit unhealthy fat people get when eating burgers and cola. Comfrey  is a slow release natural food

Plants that are fed with a slow release natural food, grow normally are healthy and more able to resist most attacks by pest or disease. 

Adding plenty of organic matter to the soil and the occasional feed of Comfrey tea provides all the food garden planted fruit, vegetables and flowers need. Feeding to much fast-release fertiliser is a bit like feeding kids a diet of fast food and sugar, providing a short burst of energy, but leaving them unhealthy in the longer term.

Plants grown in containers, hanging baskets  or poor garden soil will need feeding to get the best from them in both quality and quantity.

What nutrients do plants need and Comfrey provides.

  • Nitrogen encourages green growth, 
  • Potassium encourages healthy flowers, vegetables and fruits, 
  • Phosphorous is essential for healthy roots. 

Whilst it is rare for garden soil to be noticeably deficient in any of these, very sandy, very acidic soils, or land that has been used for intensively grown crops can be deficient, and will benefit from regular mulching with home-made compost from your heap and a feed of Comfrey liquid. Garden vegetables grown close together because of a lack of space will also benefit from a dose of potassium.

Signs of potassium deficiency to look out for are a bluish tinge to older leaves, yellowing between the veins of leaves and if left to late, stunting of growth and a failure to produce many fruits or flowers, but if spotted early and fed with a potassium-rich feed the plants will recover. Some plants like tomatoes and potatoes are very sensitive to low potassium levels. The tomato fruits, can remain green and hard and sometimes hollow. Potatoes, may turn black when cooked.

Calcium.  Plants need calcium for the growth of its young roots and shoots. Without calcium, plants can't grow. However, calcium deficiency in the soil is very rare. Not watering evenly (to dry, then to wet) is the main cause of calcium deficiency.

Why buy artificial potassium-rich feeds when it is so easy to make your own using comfrey leaves, I have explained how to make comfrey liquid feed below, or if you prefer, buy it from a neighbour gardener or supplier who makes there own.  

Comfrey is very effective at taking up nutrients  and goodness from the soil and storing it in its leaves. So no reason to over-feed your garden plants with artificial off-the-shelf fast-release fertilisers. Tap into nature's store.


How to grow Comfrey plants to make liquid fertiliser

  • Planting. Comfrey will grow on most soil types, but doesn't like chalky soil, doing particularly well in good rich organic soil in full sun. 
  • If you plant Bocking 14 seedlings in spring you will be getting your first leaf harvest before the end of the growing season. Allow 60–90 cm between plants.
  • Maintenance. Once established, it needs very little maintenance. However to maximise your comfrey crop, extra feeding with manure and compost or grass clippings will all help produce more leaves. Remove flowering stems in the first season to gain maximum leaf growth next year.
  • Root cuttings. In subsequent years comfrey plants can easily be grown from root cuttings. Cut 2-6 inch lengths of healthy root and plant horizontally 2-8 inches deep.

This is how I make liquid fertiliser from home grown comfrey plants

  • Cut the stem at ground level and strip the leaves, fill a bucket with comfrey leaves held down with a brick or large stone and then top it up with water. The rotting leaves in the bucket will turn into a sludge.
  • After three weeks, strain it through a garden sieve into a waterproof container with a secure lid to make a liquid feed. Before using the comfrey liquid fertiliser, dilute it with water to a ratio of 1:10 and apply either to the leaves or roots.
  • You can also put the leaves onto the compost heap or directly onto the soil as a plant fertiliser.
  • Best to wear gloves when handling comfrey, as the stems are covered in stiff hairs that can irritate the skin.
  • You can cut comfrey throughout the growing season stopping in September to allow a final autumn growth before winter.

Can I buy Comfrey fertiliser?

Yes you can purchase it now, if you don't have the time to make your own, I recommend this I litre pack of pellets, simply add water to make up to 75 litres. Store pellets in a dry place and the pack will last a long long time.

Just follow the simple instructions on the pack to make a Natural plant feed and soil conditioner. NPK, trace elements, vitamins, minerals and hormones.