Book review: The Year-Round Solar Greenhouse

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This time of year, many vegetable growers are still trying to extend their growing season and others are gearing up to continue growing straight through the winter. In planning for my own vegetable production, I wanted to learn more about season extension and year-round growing techniques. I discovered The Year-Round Solar Greenhouse by Lindsey Schiller and Mark Plinke and wanted to read it. I received a free copy of this book from the publisher in exchange for an honest review.

In thinking about building or buying my own greenhouse, I want to make sure that I have as much information as possible including about different materials and designs. Additionally, it’s important to me to ensure that the structure will be as energy and cost efficient as possible. This book was perfect because it focuses on creating a net-zero energy greenhouse.

In the first section, the authors share seven principles of solar greenhouse design and explain how they differ from traditional greenhouses. A solar greenhouse is defined as a greenhouse that “uses the sun’s energy not only for growth, but also for passive heating; thus, it is able to maintain suitable growing temperatures without reliance on fossil fuels.” If that sounds appealing to you, definitely check out this book. The book is then divided into the following sections:

Designing and Building a Solar Greenhouse

The authors stress that there is no perfect greenhouse design for all situations. Your climate, goals, and budget should all be considered when choosing your design. This section covers critical aspects of developing a plan for the greenhouse including siting and orientation, glazing, insulation (of walls, the roof, and underground), and ventilation. There is a very helpful table comparing different types of glazing materials in terms of quality, cost, and light transmittance as well as a table comparing different ventilation methods.

A “greenhouse geometries” chapter compares the pros and cons of the six most common greenhouse shapes (A-frame, shed roof, gable roof, “salt box” roof, arched, and geodesic domes) with drawings accompanying each style. I was surprised to learn that the biggest difference in solar greenhouse designs is the roof. The type of roof selected impacts what materials should be used, cost, dimensions, and the appropriate glazing-to-insulation ratio. In the “Construction Basics” chapter, the authors explain that wood/stick framing is the most common greenhouse construction method but they also provide another table comparing five other construction methods and discuss foundation types, siding, and finishes.

I particularly liked the chapters about attached and earth-shelter greenhouses. I learned that attached greenhouses can provide an excellent source of heat and oxygen to your home as well as can help to control humidity. On the other hand, they may attract pests into the home if they’re not properly contained, may require costly permits, and may contribute to excessive heat or humidity. Underground greenhouses, which were discussed, include garden pools, pit greenhouses or “Walipinis”, and earth-sheltered greenhouses.

Heating and Cooling Methods

In this section, the concept of passive thermal mass is explained – essentially the purpose is to store heat. I learned that water is the most economical and effective form of passive thermal mass. Ground-to-Air Heat Transfer (GAHT) systems are also described as a mechanism for using the soil under the greenhouse to store heat. For those interested in implementing aquaponic systems, the next chapter about solar hot water systems is also useful. These systems can provide both space and water heating in your greenhouse. Strategies for using wood or compost to heat your greenhouse – rocket mass stoves and compost heaters—are also covered in this section. The pros, cons, and ideal situation for each of these heating and cooling strategies are compared in a table. Considering that several of the heating and cooling options require electricity, the section concludes with methods of equipping your greenhouse with conventional power or implementing a passive (non-electrical, off-grid) solar greenhouse.

Growing in the Greenhouse

In the last section, Schiller and Plinke discuss greenhouse floor plans and share their opinions about integrating chickens, worms, and bees into your greenhouse. I was surprised to read that some people add hammocks and hot tubs to their greenhouse. I think those would be particularly lovely in a warm greenhouse during the winter!

Soil building strategies, planting plans (types of plants, crop scheduling, and record keeping), pest management, and watering systems are also covered. Additionally, there is a chapter about aquaponic and hydroponic systems in solar greenhouses and how they can increase crop yields while minimizing water usage. If you’re considering either of those systems, the authors recommend factoring them into your greenhouse design early on.

Takeaways and Case Studies

Some of the sections in the book were very complex, so I found the brief and simplified “takeaways” at the end of each section to be very helpful. Also, each section includes citations and suggestions for further reading.

About 15 case studies were included in the book, which I thought made complicated information more accessible and memorable. For example, there was a case study about Growing Power’s aquaponic greenhouses in Milwaukee, Wisconsin. This farm turns food waste into compost, which both heats their greenhouses and is sold as compost to local gardeners. Another case study was about an atrium greenhouse in which banana trees are grown high in the Rocky Mountains.

Janie Hynson is an aspiring homesteader in North Carolina. She recently moved back to her hometown after living in Boston for six years and then traveling across the U.S. working on organic farms. Janie works in public health and sustainable agriculture and is interested in how health can be improved through homesteading.