GROWING WITH GREENHOUSES
All things considered, gardening can be thought of as the art and science of environmental engineering. When we grow plants we take great care to control the soil, water quality, amount of sunlight, fertilizer, and numerous other factors to provide the best possible ecosystem for them to thrive and grow. As technology and our scientific understanding of the systems plants rely on improves we are able to seize ever-increasing levels of control over these systems. Few gardening innovations embody this mentality more completely than greenhouses.
The concept behind greenhouses is simple; growing plants in an enclosed space that allows for the entry of sunlight creates a controlled microclimate that can be managed to be warmer — or in some cases, cooler — than the surrounding environment. In this way it becomes possible to grow plants far outside the biomes in which they were originally adapted to survive. The historical record references this practice at least as far back as the Romans, who would grow plants in containers draped in oiled cloth or selenite to keep them warm. Later the practice of building greenhouses became popular in Northern Europe, particularly England and the Netherlands, in order to grow local plants out of season as well as tropical plants that would ordinarily be impossible to cultivate in the cooler climate. Many of the modern innovations in greenhouse technology were developed in the Netherlands, and to this day several of the world’s largest greenhouses reside there.
While greenhouses are most known for their ability to create warmer spaces for plants to grow, other controls made possible by enclosing an environment also play a large role in creating optimal growing conditions. A fully-enclosed greenhouse allows a gardener to exercise tight control over the atmosphere in the ecosystem. By controlling the ventilation of the air inside the enclosure with the air in the outside environment one can micromanage environmental features such as humidity, pests, and pollinator access. Some experimental gardeners have taken this a step further by supplementing the air in their greenhouses with carbon dioxide in order to accelerate plant growth and encourage the development of secondary metabolites.
The simple concepts and materials behind greenhouse construction mean that even a modest home gardener can take advantage, but these ideas can also be applied on a very large scale. Commercial greenhouses often provide a large portion of the supply of crops in cooler regions, in large part due to the increased yield that is possible when growing with tight environmental controls. Some experiments have been done to take this idea even further, constructing enormous geodesic domes that house entire self-contained biomes, not just for food production but also to provide a stable, natural environment for recreational purposes. With the engineered ecosystems provided by greenhouses the sky is the limit, and future innovations will only increase their effectiveness.