Ancient Soil Amendments: Night Soil

This is the seventh in a series of blogs, about ancient soil amendments used in the garden. Each blog will discuss a common and specific type of soil amendment used in the garden, along with documentation for its use, as well as occasionally discussing why a particular soil amendment was chosen, or its relation to modern gardening practices. The original blogs, along with other gardening related blogs, can be found here.

Fancy name for a not so fancy product, and definitely not for the faint of heart. If you are easily queasy, this may not be the blog for you.

I first learned about using night soil in gardening when watching a reality TV show where modern people had to survive life in a Victorian world. The modern term is “fecal sludge” – so yes, if you had any doubts – night soil is human excrement.

Now days the idea of spreading human waste on a garden seems downright barbaric. I polled a number of my eco-friendly minded and garden-loving friends just to see how they took it, and without fail the reaction was horrified. However, this concept is not new – and it is making a comeback. From complicated operations which create marketable “biosolids” to complicated systems which turn human waste into pelletized fertilizers, human waste as fertilizer is not just for hippies anymore.

However, if we go back in time, before the Victorian nightmen (as they were called), we have the Tudor English gong farmer. Gong farmers were considered to be well paid (six pence a day during Queen Elizabeth I’s reign), but it was not a job for the faint of heart. At the end of the 14th century, there were 16 public bathrooms for 30,000 people – most of whom lacked private latrines. These workers collected the waste and sent it to the countryside, where it could be spread on the fields (Havlicek, Pokorna & Zalesak, Waste Management and Attitudes towards Cleanliness in Medieval Central Europe, 2017).

In Geoponika, Florentinus writes of human waste and calls it better than animal dung (p87). Zadoks (Crop Protection in Medieval Agriculture, 2013) found other authors who wrote specifically of the use of human waste as well, it was believed to be free of weeds, which is why it was considered superior. He also shares Augustín the Prior’s discussion on how much Jewish farmers fertilized crops and suggests that they likely used night soil. Night soil was also recommended to be smeared on the roots of trees to protect it from insects.

What are the benefits of using night soil in the garden? According to Rachel Dring, of the Sustainable Food Trust, it “provide[s] nitrogen, phosphorous and potassium in a less soluble form than farmyard manure and artificial fertilisers, which means [it will] remain in the soil for longer and [is] less prone to leaching into groundwater or run-off, which pollutes waterways. Biosolids also contain useful levels of sulphur and magnesium and trace levels of micronutrients. Unlike artificial fertilisers, biosolids contain 20%–80% organic matter, which is critical for the health of soils.” It seems if you can get over the ick factor, there may be something to using human waste in the garden.