The Walled Kitchen Garden
The best walls were constructed with bricks and lime mortar, as the bricks retained heat and the mortar provided a place for the nails supporting the wall fruit trees. A large garden would need a huge quantity of bricks.
In a letter to ‘Capability' Brown of 1767, the Earl of Suffolk anxiously enquires whether his present stock of 650,000 bricks will be sufficient for his new kitchen garden (BL correspondence ADD69795).
However brick was expensive, and alternatives were often used. These alternatives usually reflected the geographical location of the garden: for instance, stone was often used in Wales and Scotland, and in northern and south-west England. But stone was considered cold and damp, so the most important inward, south-facing walls were often lined with brick. Cob walls are very common in chalk districts, but they need to be protected by efficient copings.
Another way to avoid the expense of brick, particularly after the Brick Tax was instituted in 1784, was to build a serpentine or zig-zag wall. Often known as ‘crinkle-crankle' walls, the wavy line provided a stronger structure. This meant that the walls could be just one brick thick, allowing a saving of about one third in bricks and thus incurring less expense (O'Neill). Examples can be found at West Dean in Sussex, Parham Hall in Suffolk and Hopton Hall in Derbyshire.
The walls created a protected environment for the crops, both from the elements and from thieves. The height of the walls varied, but in order to provide enough growing space for the trees trained against them they needed to be at least 10-12 feet high.
Usually the northernmost wall was the highest, to allow for the vineries and lean-to glasshouses placed on the southern side. The southernmost wall was usually the lowest, as this was the least important wall, and in some cases it was omitted altogether, either to avoid creating a frost pocket or to cut down on costs.
From the 18th to the mid-19th century heated walls (also known as ‘hot walls') were quite common, especially in the North. The first recorded hot wall was at Belvoir Castle in 1718 (Green). Usually (but not always) the northernmost wall, it was wider than a normal wall in order to accommodate the serpentine flues within. These ran from a small fireplace at the bottom of the wall up to a chimney at the top.
There are many contemporary descriptions for the building of hot walls, but the general consensus was that the heat from one fire grate could heat 40 feet of wall. Fires would have been lit in the early spring in order to protect the fruit blossom from frost. Examples of these heated or flued walls can be found at Belsay Hall in Northumberland, Tatton Park in Cheshire and Croxteth Hall, Liverpool.
Improvements in the technology for heating, from around the 1840s, combined with more efficient glasshouses, made these walls largely redundant.