New Walls and Old Tricks

fruitwall 1“We are being told to eat local and seasonal food, either because other crops have been transported over long distances, or because they are grown in energy-intensive greenhouses. But it wasn’t always like that.”
~ Kris De Decker

Back in the old days, everyone that could had a garden. Our lot, created in the 1850’s, not only hosted a substantial brick house, but had room for a hand-dug well, ash pit, privy and fruit trees, two of which survived well past the 1970’s when I got the place. Thirty-foot high apple and pear trees are amazing to see, even of the fruit is not very useable. (The apple tree blew down in a storm a couple of years ago.)

I think the home garden trend existed through WWII’s Victory Gardens, but later, even when the suburbs gave more people single family homes on their own lots, the age of mass markets, better refrigeration and frozen foods curtailed enthusiasm for growing your own vegetables and fruit.

Of course, nowadays people want to insure their food is organic or even just fresher. In addition, being a locavore is culturally trendy and more people just prefer their home-grown food. (You don’t get much argument about the preference for home-grown tomatoes versus store-bought.)

There also seems to be considerable interest these days in trying out new gardening ideas. Our raised beds work really well for the veggies (not to mention my back), and drip irrigation, crop rotation, biological pest control, hydroponics and advanced composting all seem like attractive concepts for interested gardeners to try out.

It may be that we should also try out some of the technologies used in the old days before cheap transportation made ready access to fresh vegetables and fruits seasonally independent. Author Kris De Decker discusses ‘fruit walls’, a method used throughout Europe designed to provide a buffer to the wind and mitigation of low temperatures. Generally, any south-facing wall could be used to store heat, block the wind, and provide a place for vegetation. Fruit walls were placed and designed to facilitate these attributes and often dozens or hundreds of the walls were arranged in rows for large gardens or farms.

These fruit walls “stored the heat from the sun and released it at night, creating a microclimate that could increase the temperature by more than 10°C (18°F)”. This technology allowed Mediterranean fruits and vegetables to be grown as far north as England and the Netherlands, using only the energy from the sun, stored as heat in the walls of the gardens. In addition, “Protruding roof tiles or wooden canopies often shielded the fruit trees from rain, hail and bird droppings. Sometimes, mats could be suspended from the walls in case of bad weather.”

The warm wall surface offered excellent growing space. De Decker notes, “The French quickly started to refine the technology by pruning the branches of fruit trees in such ways that they could be attached to a wooden frame on the wall … This practice, which is known as “espalier”, allowed them to optimize the use of available space and to further improve upon the growth conditions. The fruit trees were placed some distance from the wall to give sufficient space for the roots underground and to provide for good air circulation and pest control above ground.”

Another refinement to the fruit walls was the addition of a transparent sheet to help collect and retain heat. According to De Decker, “The greenhouse was invented by the Romans in the second century AD. Unfortunately, the technology disappeared when the Western Roman Empire collapsed. The Romans could produce large glass plates, and built greenhouses against brick walls.” Large sheet glass technology didn’t reappear in Europe until the 1800’s, although greenhouse technology was in use in Asia much earlier. Early fruit wall greenhouses were gradually replaced by heated all-glass greenhouses, as fuel became cheaper and more readily available, even though they were less energy efficient.

Other variations on the fruit wall included serpentine or “crinkle crankle” walls that optimized the wall surface and reduced building materials through thinner walls. “Counter-espaliers” were short walls opposite the principal fruit walls that helped moderate the microclimate. Later additions to lengthen the growing season into cold months were “hot walls”, using horizontal flues inside the wall that opened into chimneys on top of the wall. “Initially, the hollow walls were heated by fires lit inside, or by small furnaces located at the back of the wall. During the second half of the nineteenth century, more and more heated fruit walls were warmed by hot water pipes,”

Gradually, the availability of fast and lower cost transportation undercut the need for commercial-scale fruit walls, although fruit walls and greenhouses continued to be used for home gardens. Cheap energy continues to make commercial all-glass greenhouses profitable for flowers, herbs, certain fruits and (recently) marijuana.

However, if you are a home gardener and have a suitable space, consider adapting that masonry or concrete wall into a fundamental part of your garden.

Your tomatoes will thank you.

Additional Information:
Kris De Decker, Fruit Walls: Urban Farming in the 1600s, 12/24/15 (reprint 10/24/18), LOW←TECH MAGAZINE

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