Hair in a compost heap.

Can You Really Compost Hair? Here’s What The Science Says

I remember asking a hairdresser if I could collect hair from her. I’ll never forget the look she gave me. Even after I explained it was for my compost heap, she still seemed to think I was rather strange. Eventually, she swept up my hair and put in a bag for me – but there wasn’t very much of it. 

As you can guess from my brief story, the answer is yes, you can compost hair – both from human and pets. In fact, as you can see from the nutritional breakdown, it’s a very good green (high nitrogen) material for your compost. 

Human Hair Nutrient Values

Nitrogen16.5%
Phosphorus0.01%
Potassium K0.01%
Magnesium0.05%
Sulfur0.23
Source: Zheljazkov et al, 2008

That high nitrogen means it’s great mixed with brown (high carbon) materials. It’s worth noting that despite being a green (a high nitrogen material), it does degrade slowly. However, research (see below) has shown it can be composted successfully. 

If you have pets, you could also compost their hair – in fact, sheep’s wool is considered a very fine compost material. With human or animal hair (or wool), the key is to shake it in rather than add large amounts. Otherwise it can clump together otherwise, especially if you are lucky enough to have large amounts. 

What does the research say about composting human hair?

Research suggests that human hair is good for compost.

For example, a 2016 study by Karak at al found that including human hair increased nitrogen, potassium and potassium in compost. High levels of human hair could affect germination rates, but the amounts used are unlikely to be a problem for amateur composters. 

A 2016 study by Rahman et al investigated human hair to synthesise nitrogen for a liquid fertiliser. The researchers concluded that human hair worked better than a commercial fertiliser.  A further study Barenna et al looked at solutions for tanners looking to get rid of animal hair. Combining it with raw sludge led to a stable compost product. 

Historical Note

Hair is usually swept up and thrown in the bin – but this hasn’t always been the case. Historically, human and animal hair was used as a soil amendment to enrich the soil with nitrogen and other essential nutrients. 

In traditional Chinese agriculture, human hair was mixed with cattle dung to create compost that was applied to fields during the winter. In India, hair was even used directly as fertilizer for fruit and vegetable crops, and to make organic manures. (Source: Human Loop: History of Hair.)

A word of warning…

There are a couple of drawbacks, though. As you can imagine, one is that strange look hairdressers give you when you ask for their hair! During Covid, when hairdressers were shut, my wife started cutting my hair, but the hair from one person every few months doesn’t make much of a difference. (My wife has more hair, but is strangely reluctant for me to cut hers.)

Most hairdressers also use products such as hairspray and gel. These may or may not be fine to use, depending on the ingredients in them, but I suspect you may get more strange looks when you ask if you can inspect them! 

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