This is the fifth 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.

A cover crop is exactly that – a crop which covers a field. Another term, green manure, is sometimes used when referring to cover crops, because the idea with a cover crop is that they will be turned back into the soil rather than being harvested. Living mulches must be made up of perennial plants, where as in general, cover crops are annuals.

Lupines are discussed at length as a cover crop. Here are two examples from Geoponika: “If the land is pervaded by roots you can sow lupines therein, cut them when they are in flower and plough it in so that the cut parts are turned under, and leave it after applying a thin layer of manure to it.” (GE 3-10.8). “Lupine has to be sown in exhausted soil, not needing manure, because it serves as fertilizer: in effect, it fertilizes whatever devitalized soil and makes it productive again.” (GE 2-3.9.6) Cato says of cover crops: “Crops which fertilize land: Lupines, beans, and vetch.”

These excerpts suggest that our ancient gardening ancestors knew without science what we now know – that lupines fix atmospheric nitrogen and use their taproots to reach down into lower layers of soil.

Though clover is a particularly popular cover crop, it is not the only one. The use of winter cover crops such as oats, barley and winter rye as a way to provide biomass and reduce soil erosion is frequently used in modern farming.

Legumes (like peas) and some brassicas (like radishes) are also common cover crops. Other cover crops noted by medieval authors include fava beans, oats, and hemp and later during the 14th century weeds became a cover crop (Zadocks, 2013).

This is the fourth 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.

The use of food waste as a soil amendment is hardly ever specifically referred to in medieval and pre-medieval gardening texts. This might seem unusual – if you were to do a web search on what to do with your food waste right now, many of the first suggestions revolve around putting it into a compost or vermiculture bin. However, despite the lack of extensive specific references, it is probable this is what the medieval farmer did as well ( in addition of course, using it in a number of other ways).

First – it is safe to say there was probably very less food waste in the way we think of it now. The Forme of Cury specifically states to peel, or scrape, fruit or vegetables – but it is doubtful that such peelings went straight to the compost. There are medieval recipes that intentionally make use of modern waste items, such as entrails, and one of the easiest ways to make a broth heartier is to boil down left-over bits of vegetables (onion skins, celery tops and carrot ends) with bones.

Second, sometimes food waste was used to feed animals, much as it is now. Pigs and chickens are fairly non-discriminating with human food waste, so why would you simply throw old food out if you could use it to help feed your future food. Indeed, although pigs are cited in Geoponika as primarily eating acorns, and great forests are planted just for this purpose, later medieval farmers fed them food-waste.

Finally, we come to using food waste for compost or manure. In Geoponika, Florentinus shares that “some people dig a deep pit and cart all manure to it, the better with the worse, and rot it: into this goes … food waste” (p87). Havlicek, Pokorna and Zalesak (2017) talk about the creation of square pits which were used within cities as waste disposal sites much like the ones suggested by Florentinus. This advice, along with advice of Roman authors such as Varro and Columella would have been accessible to the medieval man. And though I am unaware of an explicit statement to use food waste in gardening during the medieval period, Richard Jones shares how it again becomes a stated practice during the post-medieval period.

Despite the lack of explicit statements however, it has long been assumed that the relatively few numbers of middens (Astill, G. Fields pp 63-85), (and how others are surprisingly small and seem to be poorly placed, suggest that most food waste was likely reused in some fashion. Additionally, the amount of pottery and bone found spread around fields and backyards suggests it was intentionally spread there (Pottery and Social Life in Medieval England, B. Jervis, 2014) – probably mixed with food waste – in an attempt to improve soils. Thus – it is safe to say, as a medieval gardener, should you want to turn your food waste into compost, you would not be out of the ordinary.