This is the sixth 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.

There is a time and place for ash in the garden. High in lime and potassium (and containing carbon, calcium, and magnesium), if you burn wood you automatically generate it for free and without the work necessary to obtain other fertilizers. Free fertilizer and soil building is always nice.

Apples in particular apparently like ash, but young plants might burn if it is placed on their tender leaves. Slugs and snails are reluctant to cross dry ashes, but overall ash is considered very alkline so most garden reference materials say to use it carefully.

Varro talks about using ash – specifically in areas where there is no
natural “salt”, and how the locals in these places instead added “salty coals” obtained from “certain kinds of woods.” Interestingly, what type of
wood you burn makes a difference when determining the fertilizer value, so the reference Varro makes to “certain kinds of woods” is not just ancient fortunetelling.  Columella says that good farmers should use ashes when creating “manure” for the garden.

Beyond as a soil amendment, there are a variety of other ways ash was used in the garden. Ibn al-‘Awwām said to use ashes of fig or oak to help yellowing trees (Crop Protection in Medieval Agriculture, p114, J. Zadoks, 2013). Ashes were spread alone or added to mixtures which were then spread on plants (from trees to young vegetables) as a way to stop all manner of insects, and spread over young plants to help protect them from night frost.

Pliny suggests ashes are a more gentle salt, and useful for keeping figs and rue from rotting at the roots and an early 17th century author suggests using ash from holm oak as a way to get rid of voles (Zadoks, 2013). In the Geoponika, Didymos says ashes “are the best” because it also kills fleas and borer beetles beyond its natural benefits to the soil (p248). In fact, there are 20 references to the ways a farmer can use ashes in Geoponika.

Clearly, ashes were a pretty common addition to the garden, especially since many of the plants that don’t particularly like them (potatoes and blueberries, for example) are New World plants. If you want a quick way to garden like a medieval gardener – ashes are an easy way to get started!

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.

This is the third 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.

When discussing chaff in relation to soil amendments, it is important to understand what is meant. Chaff is an old word – from Old English ceaf, and in every definition it refers to the removed dry husks or shells of grains through the process of threshing and winnowing.

There is a detailed explanation in the Geoponika of which types of chaff are best to use in soil building from Varro, which mentions bean, barley and wheat husks (p88, Geoponika, trans. A. Dalby) used to help offset salty soil. This is interesting because Varro included bean husk as a type of chaff, where as other Cato separates the two.

Says Didymos in the same chapter (p89), chaff is okay for roots, but harmful to all manner of fruit, shoots, leaves and green vegetables (whose leaves it pierces). He warns to not place it upwind of farm buildings or pleasure gardens as well for it can cause eye-loss.

Cato talks of making a compost which includes straw, bean stalks and husks and “chaff” in Chapter 37, most likely meaning in this case, specifically grain chaff.

Of course, to use chaff as a soil additive straight would likely have been uncommon. Florentinus mentions ash from chaff in manure, but most other mentions within the Geoponika of chaff use it as a bedding for animals, feed for them, or storage substance (for a variety of foods including grapes and onions). The 15th century play Mankind shares the following proverb: “corn servit bredibus, chaffe horsibus, straw firybusque,” reminding us that chaff was supposed to be used as horse-feed.

Among other uses, Hamerow, Hollevoet and Vince (2016) discussed the use of chaff in Anglo-Saxon England to temper pottery. In Frederic Weaver’s book of Somerset Wills from the 14th and 15th centuries there are three instances of chaff-stuffed beds. In Medieval Merchant Ventures: Collected Studies, EM Carus-Wilson mentions a chaff-stuffed pillow. This practice continued into the 19th century, when the steps to fill the beds were outlined, and such beds were considered superior to straight straw. Finally chaff is even found in thatch and daub from medieval buildings (p43, Food in Medieval England: Diet and Nutrition).

Obviously chaff was used for so many other things, using it as a soil additive would only have been preferable if it was necessary – for instance, to help salty soil – or if the chaff was no longer useful for any other thing.

This is the second 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.

Manure is talked about quite frequently in husbandry and gardening texts of the period. Manure is unique in that it is both a substance you add to the soil as well as a practice you regularly complete. In the modern mind, manure is is synonymous with animal waste. This is not true in medieval texts. Sometimes manure means animal waste, other times it means anything biodegradable.

Medieval authors compare the dung of different animals as well. Cato outlines specifically that you can just spread pigeon dung on your fields, but you should store piles of other animal waste. Geoponika also discusses the benefits that come from different animal wastes. Walter of Henley warns his readers that manure alone will only benefit your soil for two or three years.

Although the practice is documented as post-medieval, the use of manure to heat winter cold frames is one that could easily have been used. There was a Victorian practice where a brick or stone box was combined with fresh, hot manure, giving several weeks of early heat to plants. Eve Otmar of The Colonial Williamsburg Foundation told me you would get about 4-6 weeks extra heat using this method.