How to make natural compost activator yourself?



We are in the middle of winter…a hard one in NYC….lots of snow…

So we need to think about spring , flowers and…plants….Gardening….

I’m very curious about organic gardening that’s why I decided to introduce to you too amazing plants called nettle and comfrey used to activate compost.

Quick reminder: compost is a mix of nitrogen rich materials(greens,food scraps) and carbon rich materials(browns,leaves,woodchips) plus air and water.



When you make compost , you are doing what nature is doing on its own in the forest floor full of HUMUS (same thing as compost).


If you decide to do a vegetable garden you need between 5% and 20% of organic matter in your soil.So you are using top soil mixed with compost.

The NYC Department of Sanitation created the NYC Compost Project in 1993 to provide compost education and outreach to NYC residents, schools, community gardens, nonprofits and businesses.

You will find valuable information on Worm Bin troubleshooting guide, red wiggler worm worksheet with coloring activity for children, plan to build compost bins and Master Composter certificate course Here.


In France, bodies of serious research exist supporting the various benefits of applying nettle tea to your plants. Much as is the case for kelp emulsion, nettle tea seems to stimulate the ‘immune system’ of plants, making them more resistant to insect and disease attacks. Perhaps this effect is due to no more than the fact that the plant is in a state of optimal and balanced nutrition.Find out more here.





Nettle and comfrey are exceptional plants rich in nitrogen and minerals.

It is very good for your compost pile to add nitrogen fixing plants.


NETTLE:Urtica dioica



image ortie stinging nettle


Nettles contain a lot of nitrogen and so are used as a compost activator or can be used to make a liquid fertilizer full of magnesium, sulfur and iron.

Nettles act as an accelerator for compost, and a rich source of nitrogen and minerals.

Plus it’s a source of vitamin A and C.


Nettles are alleged to be anti-inflammatory (and generally helpful with all skin conditions), anti parasitic, antiseptic, a digestive stimulant, and a menstrual promoter. It may cure rheumatism, arthritis muscle wastage problems, inflammation. The nettle has been used medicinally by the Greeks and later the Romans. In fact, it has been alleged to cure almost everything. (Wikipedia)

COMFREY:Symphytum peregrinum or Symphytum officinale


Comfrey is a particularly valuable source of fertility to the organic gardener. It is very deep rooted and acts as a dynamic accumulator mining a host of nutrients from the soil. These are then made available through its fast-growing leaves (up to 4-5 pounds per plant per cut) which, lacking fibres, quickly break down to a thick black liquid. There is also no risk of nitrogen robbery when comfrey is dug into the soil as the C:N ratio of the leaves is lower than that of well-rotted compost. Comfrey is an excellent source of potassium, an essential plant nutrient needed for flower, seed and fruit production. Its leaves contain 2-3 times more potassium than farmyard manure, mined from deep in the subsoil, tapping into reserves that would not normally be available to plants.

There are various ways in which comfrey can be used as a fertilizer:

comfrey as a compost activator

*include comfrey in the compost heap to add nitrogen and help to heat the heap. Comfrey should not be added in quantity as it will quickly break down into a dark sludgy liquid that needs to be balanced with more fibrous, carbon-rich material.



How to make Nettle liquid fertilizer:


Put the stems and fresh leaves eventually the roots in a non metallic container under a weight cover with rain water

(or let tap water stay outside in open buckets for a day to remove chlorine).

Let it decompose for 2 weeks you can mix from time to time.

A typical smell will appear…you will have then a thick black concentrated liquid.

Filter the liquid with a fabric and dilute it at 10-20% with water.

The stinging nettle tea is a regulator of the iron and nitrogen in the soil. It stimulates the growth of plants, protects them from diseases and enable the transformation of organic material in humus.

Use it on the soil and plants every two weeks.

After dilution at 10-20% use it on plants that you want to stimulate the leave’s growth.

Do not use on fruits or vegetables that you want to keep for a long time before eating like pumpkin and apple tree.


Comfrey (Symphytum peregrinum or Symphytum officinale) is used like stinging nettle (Urtica dioica)

For the Symphytum officinale do the same thing make sure you add 1kg(about 2lb)of fresh comfrey

in 10 liters of water.

This is very good for vegetables producing fruits.

Make sure you let the plants with roots wilt for 48 hours before adding them to your compost or tea.



Common Horsetail: Equisetum arvense (La Prêle des champs in french)





Equisetum arvense, the field horsetail or common horsetail, is a herbaceous perennial plant, native throughout the arctic and temperate regions of the northern hemisphere.

Equisetum is used in biodynamic farming (preparation BD 508) in particularto reduce the effects ofexcessive water around plants (such as fungal growth). The high silica content of the plant reduces the impact of moisture(wikipedia)

Content: Equisetum arvense or horse tail
Procedure This plant has a very high silica content. After harvesting the leaves and stalks in spring and drying them, there are two methods to make the preparation:

*Mix the dried plant and clean water together at the rate 100g of plant to 2 litres of water. Bring it to boil and then let it simmer in a covered pan for 20 minutes and once cooled leave it stand for two days before using.

*Soak the leaves in cold water for two weeks.

You will know when the preparation is ready to use after these methods, as it has a good smell.
Storage: You can store the dried plant in a dry place for extended times. For the made up preparation, avoid exposure to light and keep cool. Store in a tightly stoppered container. Fermentation gases may need to be vented from time to time.Find out more here.


Biodynamic farming


Biological and dynamic processes in the garden include soluble nutrients, aids plant growth and disease prevention, supports earthly and cosmic forces.

Liquid extracts also aid the microbial life in the soil, roots (rhizosphere) and leaves (phyllosphere). Liquid manure and herbal teas aid the phyllosphere as cover crops aid the rhizosphere. Beneficial microbes aid in competing against disease-causing microbes. Biological extract’s foliage sprayed may cause an entire plant response called induced resistance.

‘Gardening for Life’ by Maria Thun.

For my french speaking teammates this is a complete and illustrated (sketches)book that I would like to recommend :

From “Le guide du jardin Bio” (only in FRENCH)

by Jean paul Thorez and Brigitte Lapouge-Dejean

Terre vivante


How do you accelerate your compost?


Did you ever heard of nettle or comfrey tea before as compost activator?


What do you think of biodynamic farming?


Did you ever try these liquid fertilizers in your garden?


Share your experiences.


13,171 total views, 3 views today


  1. Hi to all,
    great Blog! congratulation!

  2. Hi Nancy !
    Yes there are a lot of community gardens in NYC some have chickens,bees,rainwater harvest,trees and raised beds…
    I love them!

  3. Tamara i hope you will try it!

  4. wow Fia!!What an amazing article!So much great information!
    When I went to visit Etsy HQ I was so excited to see them saving p compost that they deliver once a week to a community garden!So awesome that more people in cities are having the chance to garden!

  5. Hi there! Thank you for this important and informative, Earthy article! Nettles are my favorite tea. My personal cure-all herb. I had no idea they were also a useful compost activator crop! How wonderful

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  7. Cory did you try doing the tea with fresh leaves of comfrey?

  8. Hi Mary and Cory!
    I am so glad that you are using it already!
    My uncle is really into it and tells me about the benefits for your plants
    when you water them with nettle tea it is the same principle of immunizations for humans but for plants..
    They are more resistant to disease and pests.
    Do you where i can order these plants?

    Also i used nettle tea for my daughter who has asthma…
    many uses…fantastic plant…
    If you have any info i will be interested.

  9. I make comfrey tea in a bucket of water from old leaves to make a compost accelerator. I am not sure if it works, but I keep doing it.

  10. Thank you for this very informative article, Fia! I have been using nettle for my own teas, and comfrey for salves. It’s great to know that they have even more uses. My compost will definitely benefit from this information.