Going soilless?

The increasing interest in hydroponic food production is not going unnoticed. Production is starting every day by a variety of people. Some are ornamental greenhouse crop growers looking to diversify. Some are starting their second careers doing something they are excited about. Some are organizations backed by investors, excited at the prospects that controlled-environment agriculture (CEA) hold. Regardless, right now there is a lot of activity in hydroponic production and CEA and the opportunities are growing.

What is causing this increased interest in food crop production? How do you get started growing your own hydroponic crops? If you are already growing, are you taking advantage of all your opportunities to increase productivity and quality? These are questions that people entering or already in the industry may have and this article is the first in a series of six articles that will serve as a hydroponic primer to provide some answers to some of these questions. This article is focused on introducing hydroponic and CEA. Subsequent articles will focus on topics including: hydroponic systems, water and nutrition, temperature, light and gases.

Why food crops in controlled environments?

Food crop production is on the rise, and there is no ignoring it. Recent data released by the U.S. Department of Agriculture showed that the value of food crops produced under protection is currently worth $797 million dollars. What is even more encouraging is that, compared to 2009, there was a 44 percent increase in the value of food crops grown under protection. What will this look like in five more years? Right now, the trend is looking very good for hydroponic producers.

Food crop production in controlled environments is increasing.

What is driving this increased production of food crops in controlled environments? There are several different factors contributing to this, including: interest in local production, increased quality, food safety and predictable yields. In many cases it may not be one of these reasons alone driving production, but rather the aggregate benefits when taken together.

Recent data released by the U.S. Department of Agriculture showed that the value of food crops produced under protection is currently worth $797 million dollars.

First, consumer interest in food has increased over the past few years. Look at the rise in interest in local foods, including local production, community-supported agriculture and farmers’ markets. However, in many parts of the country, food crops cannot be produced year-round without the use of greenhouses and controlled-environments during seasons with low temperatures and low light levels. Hydroponic production in greenhouses and controlled environments is one of the primary methods for producing food when outdoor environments are not conducive to crop production, since the controlled environment can create an environment conducive to plant growth (somewhat independent of the outdoor) ambient climate.

Another reason for increasing interest in hydroponic crop production in controlled environments is the potential for improving crop quality. Producing edible crops in hydroponic systems inside greenhouses or other controlled environments provides growers with an unprecedented amount of control compared to outdoor production in fields. The degree of control — over temperature, light, mineral nutrition, carbon dioxide, etc. — means there are more opportunities for producers to fine-tune production and make changes that improve the quality of fruits and vegetable produced in hydroponic systems. This is one of the primary value propositions for hydroponic crops — high-quality produce.

Another reason for the increased interest in hydroponic food crop production is the opportunity for increased food safety. Just like field production, there are opportunities for crop contamination. However, the nature of hydroponic production, occurring in greenhouses and controlled environments, provides more opportunities for producers to control and reduce food safety risks using protocols and practices that reduce the chances of foodborne illnesses. The smaller geographical footprint of greenhouses allows sanitation to be controlled more easily than expansive outdoor fields.

Finally, one of the biggest benefits is the predictability of harvests from hydroponic crops. Since hydroponic crops are grown in greenhouses and controlled environments that are easily manipulated by producers, sub- or supra-optimal conditions can changed to conditions more conducive to crop growth and development and keep harvests and yields on track. This is one of the strongest appeals to buyers of produce: predictability in supply.

Getting started

Are you interested in starting to produce food crops in a hydroponic system? Are you trying to get a better understanding of what you’ll need to start producing? First, let’s start with the crops you will be producing. There are a number of different crops that can be produced in greenhouses and controlled environments; however, they can be grouped into a few different categories for simplicity: 1) vine crops (tomatoes, peppers, cucumbers and eggplants); 2) leafy crops (lettuce, greens and herbs); and 3) small fruits (strawberries and brambles). There are specific production protocols for of each of these crops. However, regardless of the crop, certain principles of production environments and aspects of culture can be discussed more broadly. Temperature, light, water, nutrition, oxygen and carbon dioxide are factors that affect every food crop produced in hydroponic systems. Each subsequent article in this series is going to focus on a different aspect of hydroponic crop production, including systems, environment and culture. Our goal is that by the end of this series, you will feel comfortable and confident with knowing the fundamental aspects of hydroponic food crop production.

Stay tuned for April's Hydroponic Production Primer about the basics of hydroponic systems.

Christopher (ccurrey@iastate.edu) is an assistant professor of horticulture in the Department of Horticulture at Iowa State University.