Can You Use Human Poop As Fertilizer?


As off grid homesteaders, weʻre always looking for ways to build more soil to grow a fertile garden, especially in the tropics where soil disappears almost overnight. Humanure is a great way to do that! The image above is composted human poop from my off grid homestead. Some of the richest compost you can find.

Human poop can be used as a fertilizer after composting for 6-12 months.  Once composted, it breaks down into nitrogen rich compost that plants need for healthy growth.  It is advised to use this composted “Humanure” on trees and shrubs, rather than annuals to reduce the chance for contamination. 

Of course, you have to be careful and follow proper systems to ensure the waste is properly broken down. By following these tips in this article, youʻll have no problem recycling your human poop into nutrient-dense compost for your garden.

Difference Between Biosolids And Humanure

Before we get started, there is one thing I have to get clear.  There is a difference between waste treatment plant leftovers known as biosolids and composted human poop. 

Biosolids are the physically and chemically treated leftovers from wastewater treatment plants which turns into a nutrient-rich product also known as sewage sludge.  Humanure is human poop you collect yourself, compost for 6 – 12 months which creates a fertile compost that plants require for growth.

The controversy around using biosolids is that it’s made from everything that gets put into our sewage system. Human waste is one thing. But sewages see both domestic and industrial waste that includes heavy metals, chemicals, and pollutants. All of this then gets pumped back into our food. So biosolids do contain human poop but also have a lot of other ingredients.

Humanure is made from human poop that you collect yourself. Critics say that humanure can be dangerous to use around edible plants because pharmaceuticals and pathogens can still be present in the waste.

However, if you’re only using your family’s poop and using hot composting practices, any pathogens and diseases in humanure will be killed off during the composting process. While you might not be chemically treating the waste, you’ll also not be using heavy metals and pollutants from industrial waste in your soil.

How To Make Humanure

Here’s how to make your own fertilizer from human poop.

  1. Know the source of the poop. You don’t want to be using just anyone’s poop. Know the source of the human waste you’re using to make sure you’re not contaminating your compost with serious illness or pharmaceuticals. So, stick to your family’s excrement for making humanure.
  1. Add dry carbon. To make good compost, you’ll want to have a mix between carbon and nitrogen. Good sources of dry carbon include dry leaves, plant trimmings, paper, straw, pine needles, and straw. You want there to be more carbon than nitrogen (greens or poop) in your pile.
  1. Make a compost heap that is at least 3’ x 3’ wide and 5’ high. You need a big pile to keep the compost hot.
  1. Build static compost that slow cooks in the range of 130 – 160 degrees.  A static compost pile does not have to be turned, but you must be sure to build it properly.  By slow cooking, you ensure that all harmful pathogens are killed.  Hot compost piles that get turned often have been shown not to work as well.
  1. Let It Sit for 6 months to one year.  What I do is fill up one pallet compost bin and let it sit until the next compost bin is full.  Then it gets emptied to make room for another batch.  That takes my family of 4 about 1 year.

Best Compost Toilet That Transforms Poop To Compost

So, you’re ready to start composting your poop. But how are you going to collect it? A quick google search reveals compost toilets are expensive. Most of them are priced well over $1000.

You don’t have to pay that much for a composting toilet. In fact, you shouldn’t. You can build your own composting toilet from a 5-gallon bucket that is just as effective as the most expensive ones on the market today.

The total cost will be about $50 too.

Here’s what you’ll need:

  • Strong 5-gallon bucket
  • A compatible toilet seat
  • Compostable covering material to soak up the liquid
  • Compostable bags

Place the compostable bags in the bucket, line the bottom with something to soak up extra liquid, put the toilet seat on, and you have your very own compostable toilet.

Every time you use the toilet, you’ll put a layer of covering material instead of flushing. Every two to three days, you’ll want to empty the bucket, take the bag out and place it in your compost pile.

If you follow these directions, you can safely use your poop to create nutrient-rich humanure and avoid stinking up the bathroom while you’re at it.

Best Commercial Toilet Option

If a commercial toilet is your only option, perhaps because you are looking to have your project permitted or do not have space for a separate compost pile, there is only one compost toilet that I would suggest for you to purchase.

My favorite by far is the Natureʻs Head Composting Toilet.  Not only is this toilet NSF certified, allowing it to be permitted in some municipalities, it does pretty well at composting your waste.

It has a built in urine separator that you should replace every other day and is able to have up to 80 feces collections before it needs to be emptied.

Having a compost toilet does take some work on the owners part, but having a nutrient rich compost to spread on your plants makes it more than worth it.

Is Using Human Poop As Fertilizer Legal?

The legality of composting toilets varies from state to state. In Hawaii, for example, most NSF-certified composting toilets are legal. Sunmar and Nature’s Head are popular NSF-certified models.  What is definitely illegal is selling humanure. So keep your homemade fertilizer for your own garden.

When composting human waste, you shouldn’t have any issues if you keep your compost pile neat and smell-free.

What Plants Can You Use Humanure On?

Properly composted, Humanure is safe to use on all edible and non edible trees, shrubs and other perennials.  It is not recommended to use in vegetable gardens where edible parts of the plants can come into contact with the humanure in the soil.

Stick with fruit trees, berry bushes, and ornamental plants to be extra safe.

Human poop can be safely turned into fertilizer in your garden without donating it to waste treatment plants. You’ll be saving money on buying fertilizer and not need to worry about overfilling your septic tank if you’re off-grid.

http://humanurehandbook.com/downloads/humanure_sanitation_paper.pdf

https://www2.gnb.ca/content/gnb/en/departments/elg/environment/content/land_waste/content/composting/building_a_hot_compost_pile.html
https://www.theguardian.com/environment/2009/may/12/humanure-composting-toilets
https://www.epa.gov/biosolids/basic-information-about-biosolids

Sean Jennings

Sean has been living simply Off-Grid in Hawai'i for over 18 years. He lives debt free on Hawai'i Island with his family and over 40 chickens. When he's not tinkering around the homestead, he's off exploring the shorelines for fish & surf.

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