Funky Fridge? Make A Natural Fertilizer

by | Oct 8, 2015 | Building Soil, Living Laboratory, Permaculture, Permaculture garden, Sustainable Living | 1 comment

I’m the sort of person that quickly forgets leftovers in the fridge. So sometimes, things start to get a little funky and resemble a science experiment. So instead of throwing things straight in the compost bin, I try and take the time to make a natural fertiliser with some of the stinky fridge ingredients. We do have a great compost recipe here. And then there’s worms!

Natural or biological fertiliser is a liquid that contains living microorganisms. The role of a bio-fertiliser is to improve microorganism productivity, stimulating soil biology. When applied to plants, it aids in the growth and health of the plant, increasing the availability of primary nutrients to plants.

Natural fertilizer

Natural fertilizer


Plants basically need 16 mineral elements to function at their optimum. The most important are nitrogen (N), phosphorus (P) and potassium (K). Some conventional farmers add chemical fertilisers (NPK) to their gardens and farms. However, these fertilisers are synthetic and can cause damage to the soil, groundwater, and human health. So I like to use natural fertilisers as they are cheap to make, relatively easy and way less harmful to the soil, people and environment.

Ingredients collected:

On opening my fridge, I found garlic, funky kefir, bits of chocolate, eggshells, old seaweed and dried herbs, all good ingredients to use in a biofertiliser.

For this bio fertiliser, I will add a few green leaves. First, collect leaves from weeds or plants with a deep taproot, such as dandelion, comfrey, parsley, carrots and cabbage. These plants tend to break down easily and contain a good dose of nitrogen and other nutrients. 

Natural fertilizer

Parsley and fennel leaves are excellent for natural fertilisers.


1. Half fill a 20L bucket or barrel with collected leaves. Next, add the funky finds from your fridge. Keep it simple like yoghurt, kefir, miso scraps, tea bags and sugar, jam bits etc.
2. Fill the rest of the barrel with water.
3. Pop the lid back into the barrel. Leave the barrel in a cool place. Allow to sit for 4-6 weeks until it starts to get brownish. Make sure it is out of children’s reach.
4. Once a week, give the liquid a stir with a long stick, aerating as you go.
5. After 4 to 6 weeks, check on the liquid. You may find that the liquid smells a little off. If so, keep aerating and leave it so sit for a little longer.

Once the bio fertiliser looks like the colour of tea, gently pour off the liquid. Mix the liquid with de-chlorinated water 20:1 Ten parts water and one part bio-fertiliser. Pour directly on the soil and cover with mulch. Or pour directly on the mulch.

If you feel like you need to add more ingredients to your biofertiliser, you can also try these:

Molasses (the third boiling cycle in the sugar-making process) provide readily available carbon energy and carbohydrates to feed and stimulate beneficial micro-organisms. As a result, the biodiversity in your soil will flourish and enhance natural soil fertility. If you don’t have molasses, then maybe try brown sugar or honey.

molasses as fertiliser

Fishbones are an excellent source of phosphorous. Dry out the bones in the sun, then pound them with a pestle and mortar. Thus, creating a thick pounder that you can add to your biofertiliser.

If you want more information about natural fertilizers, check out our new eBook  How to make natural fertilizers by Lucy Legan.

How to make natural fertilisers shares many DIY recipes so that you can support soil biology and fertility in your permaculture garden.

1 Comment


  1. Funky Fridge? Make A Natural Fertiliser | DNA Reboot | WORLD ORGANIC NEWS - […] Source: Funky Fridge? Make A Natural Fertiliser | DNA Reboot […]
  2. 5 Things To Remember If You Keep Accidentally Killing Your Plants – White Rabbit Gardens - […] Natural fertiliser: Many cultures believe that “what you give out is what you get back”. This is true with…
  3. Garden success – lessons learnt in my permaculture garden – White Rabbit Gardens - […] found that if I spend time organising myself with easily accessible hay for mulching, a barrel of natural fertiliser and a…
  4. Create an edible balcony with a container garden – White Rabbit Gardens - […]  Add nutrients to the soil to keep plants happy. Use mulch and natural fertiliser. […]
  5. Could you be the solution to saving the planet? – Planet Schooling - […] is fruit and vegetables which can be easily composted. 26% is dairy which can be converted into natural fertilizers…
  6. How to compost for waste free living – Planet Schooling - […] allows you to have a continuous production of compost, making turning the pile a dream. Note the natural fertiliser barrel at…
  7. How to make a Mandala Garden – Planet Schooling - […] Plant the outside border with comfrey and lemon grass. This combination helps keep the grass out of the beds.…
  8. Free resources for permaculture living and Homeschooling during these challenging times – Planet Schooling - […] Funky Fridge? Make A Natural Fertiliser […]
  9. Free resources for permaculture living and Homeschooling during these challenging times | Planet Schooling - […] Funky Fridge? Make A Natural Fertiliser […]

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