There is an important distinction to make before investing in a structure to extend your growing season. Both a greenhouse and a high tunnel will help you accomplish this goal, but there are notable differences – in durability, use, and price – to understand before you make your ultimate decision.
Confusingly, the two terms of often used interchangeably. Your location, the crops you grow, and other variables will dictate which of these options is right for you. Shane Smith, author of The Greenhouse Gardener’s Companion, defines a greenhouse as a structure that is heated. By his simple definition, a greenhouse allows the grower to control the temperature and environment within a specific range.
Sticking with this accepted standard, an easy way to make the distinction between the two structures is that a high tunnel uses passive ventilation for air exchange and cooling. Conversely, a greenhouse is usually equipped with electricity and has automated heating and ventilation systems – more on this below. But keep this in mind when trying to explain the difference to someone else: High tunnel = passive. Greenhouse = active. This is a rudimentary understanding but usually a helpful jump-off point.
The key term here is usually. More and more, these two options are overlapping and evolving with the needs of growers. But for the purpose of this blog, we will go by the traditionally accepting definitions of each of these options.