I have always held a fascination for growing under glass since Eliot Coleman’s classic, Four Season Harvest. If we are to extend the growing season in cooler climes we need to know how to grow under cover. I started experimenting with the idea of a small greenhouse mixed with annuals and perennials cropping top fruit as well as herbs, salads and usual greenhouse summer fare. Then Jerome Osentowski and the Rocky Mountain Permaculture Institute came to my attention.
Imagine building a greenhouse high up a mountain that is capable of housing a forest garden full of fruit, vegetables, medicinals, even flowering scented jasmine in mid winter. Bliss. But what is clever about these structures is that they fully utilise passive and active solar gain and store the heat using zero fuel technology. Jerome and his architect and design partner, Michael Thompson, call this system a ‘climate battery’. The system involves circulating air below ground with fans through a network of buried perforated tubes that pushes hot, moist, ambient air from the greenhouse in the day, whilst storing heat and humidity in the soil that can be accessed at night when it is cold. This method allows the indoor climate to be finely tuned and means it is possible to create a Mediterranean climate in much colder regions with zero fossil fuel inputs.
The clever thing about this book is that it is written both for the DIY builder and also for the more ambitious technician. It explains how to build greenhouses of various sizes; gives a selection of case studies; describes how to capture energy, ventilate structures and manage water; how to build beds and keep the soil sweet; and how to use microclimates in and around the greenhouse. There are tips on what summer and winter crops to grow and how to build fertility with worm farms in the beds between crops. There is also a deep sense of the aesthetics and pleasure in these structures. This is a year round place to savour, not just a productive horticultural site.
If we are to build more resilient communities and relocalise our food system, we need to push the climatic envelope and build greenhouses like these. This book comes home with me. I want one!
Maddy Harland is editor and co-founder of PM
USA readers can buy The Forest Garden Greenhouse from the publishers in the US here: www.chelseagreen.com/the-forest-garden-greenhouse
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