Saturday, December 3, 2011

Design for Small Lean-To Greenhouses

This is a century-old design for constructing a small, glass greenhouse lean-to (or free-standing). Don't miss the seven photos that I've added at the end of the post which illustrate modern adaptations to these old instructions for your inspiration. With the abundance of materials (including recyclables) available today, please innovate to improve on this old design!

Small Greenhouses

The farmer who would make his crops of vegetables most profitable, or the small gardener who would have an early supply of early vegetables for home use or market must employ some kind of glass structures to hasten these crops. The hotbed or cold frame have been much in use in the past, but the cost of sash, shutters and mats is nearly as much as the materials needed for a permanent structure, while the labor of caring for cold frames or hotbeds is often much more than that of the small greenhouse. In the latter one may work with comfort no matter what the weather may be outside. It requires much more skill to run hotbeds successfully.

Small greenhouses may be built against the south side of the house or stable, Figures 1 and 2, or they may be built entirely away from other buildings, but the shelter of larger buildings on the north or west will be found of great advantage. If one has a basement to the house or stable, a lean-to house may be built, and heat from the open cellar in a large measure will heat the greenhouse in the mild weather of fall and spring.

Material for Construction

A cheap and efficient house may be made by setting chestnut or cedar posts in the ground, covering the sides with lining boards, then two thicknesses of tarred building paper and sheathing outside, Figure 3. Cement, stone or brick will be cheaper in the end. The durability of glass structures will depend much upon the form of the materials. Clear cypress is now more used than any other material. Sills should be of the form shown in Figure 4. Plates may be made of plank as in Figure 3, or as in Figure 5. Sash bars should have grooves along the sides to catch the drip from the glass, as in Figure 6.

The glass for ordinary work may be No. 2 double thick, large sizes, 16x 20 inches or 20 x 24 inches, being much used. Smaller sizes will be cheaper in price, but more sash bars will be needed, and they cut off much of the sunlight. The glass should be put in with putty, made with about one-third white lead in it, and firmly tacked with triangular zinc tacks of large size, or the double-pointed tacks, which are so bent as to prevent the glass form slipping down.

Set Glass in Warm Weather

Glazing should be done during the summer or early fall, as putty will soon become loose if frozen before well hardened.

In building there should be no mortises, but all joints be made by toeing in with long, slender nails. All woodwork should be thoroughly painted before fitting, and all joints filled with white lead paint. After all is done the frame should be painted before the glass is put in.

The most important and expensive feature of the small greenhouse is the heating. If one has a hot water or steam heater in the house, to which the glass house is attached, it will be a very simple matter to carry pipes through, as at a, a, Figures 1 and 2. Hot air also may be let into such houses, or a small kerosene heater in very cold weather may be used, if the house is built opening into the cellar.

Ventilators must be located as shown in Figures 1 and 2, at b, b. Very small structures may be run without much heat if opening into cellars or other heated rooms by having shutters or curtains to draw down at night and in very cold, cloudy weather.

Covering with Hotbed Sash

Houses of small size may be made by building a frame upon which hotbed sash may be screwed. If one has the sash this is a cheap way of building, and such a house has the advantage that the sash may be entirely removed during the summer, but it is very difficult to make a close house with such sash.

The woodwork of greenhouses and hotbed sash should have a coat of thin linseed oil paint every second year. Much of the success to be obtained from any glass structure will depend upon the skill of the operator, and the thermometer, both outside and in, must be watched very closely. The temperature should be maintained as nearly as possible like that in the open air under which the plants grown thrive the best.


Note that instructions are taken from the 1912 book, "Handy Farm Devices and How to Make Them" by Rolfe Cobleigh, which is online through Cornell University. [pdf]


Modern Adaptations to the Above Instructions: