How To Make Comfrey Fertilizer (Free Plant Food)

If you’re a gardening enthusiast, the idea of creating your own fertilizer is likely appealing. One simple method is to make fertilizer from Comfrey leaves. By preparing Comfrey tea, garden lovers can cater to the needs of their mature plants in an organic and natural manner.

To make comfrey tea, you will need to follow the tips below.

  • Grow Comfrey in your garden to harvest
  • Harvest the Comfrey leaves and place them in a bucket
  • Fill the bucket with water to barely cover the Comfrey.
  • Place the lid on the bucket and put it behind the shed
  • Allow 4 to 6 weeks to steep before use.

In this blog post, the tips above are essential; we will cover Comfrey in much more detail and show you two different processes to make a feed from comfrey leaves.

Two methods for comfrey tea

  • Comfrey tea made with water
  • Concentrated comfrey tea without water

There are two fundamental methods for Comfrey liquid, known as Comfrey tea, and each has a different process to make, and both have different duration in the time taken to complete.

comfrey tea in a syringe

Make Comfrey Plant Food Made With Water

Above, I gave a fundamental breakdown of the process for making Comfrey in a bit of water. Otherwise known as comfrey tea.

This is very basic and straightforward to make. If you can make a cup of tea, you can make this. Just steep the Comfrey leaves in a large bucket for a long time and make the perfect liquid fertilizer with more potassium.

The resulting liquid will become your comfrey liquid. You will need to water this down on 10/1 when feeding your plants. Or one part comfrey to ten parts water. It also requires to be stored in a dark place to prevent degradation.

Concentrated Comfrey Tea

These alternative methods for making fertilizer with many trace elements or concentrated Comfrey tea is a much longer process. However, It is a much better product to produce.

This is because It takes up much less space than the first process. It produces a dark black sticky syrupy liquid that is very concentrated, and you will only need around 10ml per liter, then add it to a watering can. It is a rich source of nutrients.

This process also has a few other benefits. It is much easier to store due to the concentration, and the product lasts longer and doesn’t smell like steeping Comfrey leaves do from the first process.

comfrey tea steeping in a white bucket

To make this concentrated comfrey tea, you must make a comfrey pipe. Comfrey leaves are placed into a setup pipe, and weight is set above. Wear gloves and long sleeves when harvesting Comfrey, as it can irritate your hands and skin.

The Comfrey leaves decompose naturally, and the resulting liquid is collected in a vessel below. The leftover pulp is an ideal compost activator. Or it can even be added to shredded leaves to speed up the leaf mold process. Another use for the pulp could be a side dressing around plants in your garden.

If you want to learn more about these methods and how to build a comfrey pipe, check out the video below, where I take you through it step by step.

Why is Comfrey good as a food?

Comfrey liquid feed is so good as a fertilizer because it belongs to a group of plants that is a dynamic accumulator.

These plants send down profound roots and soak up high nutrients from the ground that most plant species cannot reach. These deep roots hold tons of nutrition.

The plant then stores this in its tuberous root system and pushes it out through its leaves.

Comfrey feed has a fantastic NPK, which stands for Nitrogen, Phosphorus, and potassium, and for those who don’t know, along with calcium, theseium.

NPH letters made from agregates

These three nutrients are essential in plant calcium. It must be noted they are not the only nutrients required by other plants.

Having more than even composted manure, it is no wonder why so many gardeners consider looking into making their liquid feed at home using Comfrey. It is organic and, more importantly, FREE.

Compost made from just dried leaves and Comfrey is perfect for raising plants s it is nutrient-rich, light, and airy.

What Species for Comfrey feed?

All varieties of Comfrey can be used in this way. They are all accumulators and will provide the nutrition your plants require in the garden.

However, not all Comfrey is identical. Some are invasive, and others are not. They also have different colors of flowers, and it is good to promote flowers as the bees use these as a pollen source.

It is essential to understand which variety you have or wish to purchase.

Comfrey Species That is not Invasive?

There are around 35 known species of Comfrey, as seen in the chart below—however, only one cultivar that is not invasive, but more on that later.

  • Symphytum asperum – prickly Comfrey, rough Comfrey
  • Symphytum bulbosum – bulbous Comfrey
  • Symphytum caucasicum – Caucasian Comfrey
  • Symphytum ibericum – creeping Comfrey,
  • Symphytum officinale – Comfrey
  • Symphytum orientale – white Comfrey
  • Symphytum tauricum – Crimean comfrey
  • Symphytum tuberosum – tuberous Comfrey
  • Symphytum × uplandicum – Russian Comfrey, healing herb

So as mentioned, there is only one cultivar, Symphytum x uplandicum. This is a Russian variety of Comfrey classified as Bocking 14. I grow Bocking 14 at home.

Bocking 14 cannot become invasive because it is sterile and is perfect for making liquid feed. The only way to propagate Bocking 14 is by root division.

What nutrients does Comfrey have?

  • Nitrogen
  • Phosphorus
  • Potassium
  • Calcium
  • Manganese

The five primary nutrients transferred into Comfrey tea have vast amounts of calcium, which helps stop blossom end rot (BER) in tomatoes, eggplants, and peppers in established plants.

Along with the primary five nutrients, Comfrey also accumulates micronutrients beneficial to plants and B12, so this is a perfect plant to grow in the garden for a portion of nutrient-rich plant food.

plant nutrient graphic

How long does Comfrey Liquid Feed last when stored?

Making the concentrated comfrey liquid feed from these perennial plants will last for around a year. So you could make one large batch and store it until required.

Making Comfrey fertilizer with water this should be used as soon as it is ready. It will last about a month before the compounds break down.

Picture of comfrey plant in flower

How do I use Comfrey tea?

There are various ways to use liquid Comfrey feed. I will go into more detail about these as we continue. The list below is not exhaustive, but I will cover the main ones here.

  • Liquid drench
  • Foliar sprays
  • Residues can be used as a mulch

Liquid Drench

When applying liquid Comfrey feed, mix your required amount and use this as a drench. Pour this on the plant from head to foot, soaking the surrounding soil around the root zone.

Once a fortnight should be sufficient. It is perfect for feeding fruit trees and even young plants. I would not bother adding it as a feed to potting soil, though, as it will already contain nutrients.

Foliar Sprays

Mix the concentrated Comfrey liquid fertilizer with 10ml of every 1 liter of water. Add this to a spray bottle, and foliar spray the leaves of your plants. Using Comfrey is excellent as you cannot overfeed your plants.

Ensure to cover both sides of the leaves. Do this early in the morning for the best results.


The pulp or residue from making your plant food can be used as a mulch around your plants.

As it rains, this will take additional nutrients not released during the process and carry them into the soil area, making them available for your plants.

Comfrey leaves only take a few weeks to break down and release their nutrients.

Ways to Use Comfrey?
A few other ways in which Comfrey can be used in the garden.
Add the leaves to potato planting holes or trenches
Use the full-grown plant as a compost pile activator
Use comfrey leaves as a mulch
Grow Comfrey plants as a green manure
Dry and powder root and leaves as an additional feed to seed starter mix

How many times can you harvest Comfrey?
You can harvest comfrey plants up to four times a year. Even as much as every few weeks during summer.
A bed of Bocking 14 Comfrey will give you plenty of material to produce all your fertilizer at home. It will also allow you to try other uses around the house.


Making your Comfrey liquid feed is easy and has so many benefits. It saves money, keeps you organic, and feeds your plants the necessary nutrients.

It is perfect as a foliar feed to quickly get nutrition to suffering plants. Ideal for giving a quick nitrogen boost to your crops.

Providing you use the Bocking 14 strain, you have no issues with it becoming invasive. This plant is worth a spot in every garden. You can even grow it in partial shade, as its deep taproots can sustain the plant.

comfrey in the shade

I hope you got some value from this post. Or, at the very least enjoyed reading it and learning about Comfrey liquid fertilizer.

Just remember the golden rule. One part comfrey and ten parts water when used as a drench or foliar spray when spraying or feeding other plants with a side dressing.

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