Background on Moveable Greenhouses

By Eliot Coleman

I like to refer to the moveable greenhouse as "the best new gardening idea in the last 100 years." However, I should say "rediscovered new idea" since the first moveable glasshouse I know of was built a little over 100 years ago in 1898 in England.

What is new is applying the concept to the home greenhouse. The first movable greenhouse was developed by commercial vegetable growers who were looking for a better solution to greenhouse soil-sickness and the consequent build up of pests and diseases. The options at that time - removing and replacing the soil to a depth of 16 inches or sterilizing the soil with steam - both had their disadvantages in high costs and disruption of soil structure.

Once movable greenhouses, popularly known as mobiles, were perfected in the early 1900s they became the design of choice for solving greenhouse problems.

I saw my first mobile while visiting an organic market garden in Holland during the early spring of 1976. Although newly constructed it was just like the classic models I had first read about. The glass covered metal frame was 40 feet wide and 120 feet long. It sat on metal wheels running on railroad rails long enough so three different sites could be covered.

The morning I arrived the house was being moved. Even though I was familiar with the idea I will admit my surprise at seeing such a huge structure being moved so easily. A few workers on each corner were pushing it along. I was told that, except for certain special flower crops, very few mobiles were being built anymore. Most Dutch growers were solving their greenhouse soil problems with highly toxic chemical sterilization or by growing hydroponically without soil.

However, since my hosts thought hydroponic produce was tasteless (I agree), they wanted to grow real vegetables in soil and believed the mobile technology made great biological sense for their organic operation. They stressed that the same reasons which inspired the initial development of mobiles - preventing both pest build-up and soil fertility problems - still applied to those growers using natural methods.

Over the years since that 1976 visit I have experimented with numerous moveable greenhouse designs. I have used them with great success to grow a wide range of hardy vegetables without heat in winter. In summer they are filled with tomatoes, peppers, eggplants, and cucumbers. The present mobile greenhouses on my farm are almost as large as that first Dutch model I saw.

However, all of them are covered with plastic, not glass. Whereas plastic greenhouses may make economic sense for a commercial farm, I would not want one at my home. In truth, Quonset-shaped structures are some of the homeliest creations of human architecture.

Well-built glass greenhouses, on the other hand, are among the most elegant and beautiful structures. Furthermore, glass lets in more light than plastic which makes it the ideal protective covering for winter crops when the days are shorter and the sun-angle is lower. When I wanted to build a movable greenhouse next to my house I knew I wanted a glasshouse.

The models we sell combine all the best ideas from my 40 years of experience into the perfect home greenhouse.