How To Make Comfrey Fertilizer – Garden Tips 2024

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Fertilizer is an excellent way to add nutrients to the soil where your plants are growing. While there are many methods to make fertilizer, comfrey fertilizer is easy and completely organic.

How to make comfrey fertilizer: Comfrey fertilizer begins with the leaves of the comfrey plant. After they are picked, place them in a larger bucket and leave them in a cool, dark place to decompose. After six weeks, the leaves will turn into a liquid that is full of important nutrients such as potassium, phosphorus, and nitrogen.

What is comfrey fertilizer?

Comfrey fertilizer is derived from the comfrey plant, which also goes by the name of boneset as it was once used to mend broken bones. Even though there are different varieties of plants, you can use any of them to make fertilizer.

The fertilizer is made from the leaves of the plant as the nutrients are collected as they decompose. The process doesn’t take long and you are left with a mixture that is rich in nutrients.

Is comfrey a good fertilizer?

Comfrey fertilizer is a solid option because of how the plant works. While all plants have roots that bring in nutrients, comfrey differs slightly because of how large the root system is and thus how effective it is at drawing nutrients from deep in the soil.

Within comfrey fertilizer, you will have nitrogen, phosphorus, and potassium, the three major nutrients that all gardens need. This makes it a great, all-purpose fertilizer no matter what you are growing.

How long does it take to make comfrey fertilizer?

Comfrey leaves can take up to six weeks to decompose enough to turn into a liquid fertilizer. While this isn’t too long, there are ways to speed up the process.

The smaller the size of the leaves, the faster the process, so tear or cut the leaves up first before placing them in a bucket. Furthermore, if you add water, it will help with the whole process, although this can lead to an unpleasant smell.

How to make comfrey fertilizer?


It’s best to make as much comfrey fertilizer as you can in one batch to save you time and energy. Try to start with a large, five-gallon bucket.

If you want to gather the comfrey fertilizer in small batches instead of waiting for it to be done all at once, you can drill holes in the bucket. Then, place it in a larger bucket to catch the run-off.

When gathering the leaves, you will notice they have scratchy hairs along them which can be quite coarse. Be sure to have long gardening gloves ready to protect yourself.

Collect the leaves

Put on your gardening gloves and keep your sleeves rolled down. Then, gather your comfrey leaves, plucking as many of them as you can.

Fill your bucket with all the leaves you have found. Don’t be afraid to push them all down to the bottom as you want the nutrients to seep out of the leaves. To keep them in place, put a heavy rock on top.


The leaves will take about six weeks to break down. If you can push them down harder, this will speed up the process a little as they will already be broken down.

Eventually, the comfrey leaves will break down and turn into a mushy, dark green liquid. Be aware that this will smell, especially if you add water to help them break down faster.

Dilute the mixture

The comfrey mixture at this stage will be quite dense so it’s best to dilute it with water. If you have already added water to the mix to help it break down faster, make a ratio of three parts water to one part comfrey. If you are just diluting it at this stage, 10 parts water to one part comfrey is ideal.


Now that you have a finished comfrey fertilizer, you can spray the nutrient mixture on your plants. You can do this once a month for new plants to keep them as healthy as possible.

Other methods of using comfrey


If you have a compost bin, an easy way to use the entire comfrey plant is by simply tossing it inside. Cut the whole plant up, including the stem and leaves, to help speed up the process.

The comfrey plants will break down along with the other items in your compost. Then, when all the compost is finished, you can add it to your garden.


If you are short on time or don’t want a large bucket of fermenting leaves, you can simply skip this step and use the comfrey leaves as-is. Place a layer of comfrey leaves around the base of your plants.

The leaves can remain whole or, if you want a faster decomposition, you can tear them up first and then place them around your garden. Similar to tree leaves, comfrey leaves will naturally break down and their nutrients will be absorbed by the soil.

In soil

If you have a container garden, you can place a few comfrey leaves at the bottom of the pot and then fill it with soil. The leaves will naturally decompose and those nutrients will be absorbed into the soil and into the new plants.

Short tips when using comfrey fertilizer

  • Always wear gloves as the leaves are rough and scratchy.
  • On their own, comfrey leaves won’t smell too much but once mixed with water they will put off a strong odor.
  • Comfrey leaves will turn to liquid so they can’t be used as a natural leaf mold that slowly breaks down into a solid form.
  • The comfrey plant comes in many varieties but all are capable of releasing important nutrients.
  • Comfrey is also high in calcium, which many plants, such as tomatoes and peppers need.


Comfrey fertilizer takes the abundant nutrients of the comfrey plant and breaks it down so you can use it in your garden. You simply need a larger bucket and a bit of time and you can easily harvest these nutrients.

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