Protected agriculture offers added control and efficiency

In agriculture, control is key: controlling costs, controlling pests, controlling the climate. An increasing number of growers are turning to protected agriculture as the best way to get this kind of control. Growing under cover – in greenhouses, shade houses, glass houses, etc. – does offer control, but equally important is the efficiency it provides, says Eric Viramontes, CEO of the Mexican Association of Protected Horticulture (known as AMHPAC).

Growers must consider the local environment, construction costs and market prices, among other factors, to decide what protected agriculture technologies to employ. In some cases, simple shade houses suffice. These melons, though, are growing in a completely climate-controlled greenhouse in Spain. Active protected agriculture technologies allow growers to produce crops in conditions they otherwise may not be able to, and also within the optimum market window.

In fact, the ultimate goal of protected agriculture is to enhance efficiency, he emphasizes. “Protected agriculture technologies were developed to allow growers to use less water, to eliminate most chemicals, to use more organic methods of growing, to use less land to produce more yields,” says Viramontes. “It allows you to develop a high-quality product while using the resources better.”

There are about 50,000 acres of protected agriculture in Mexico right now, a number that is growing significantly every year. China is by far the largest user of protected agriculture (it is home to nearly 90 percent of the roughly 2 million acres of protected agriculture acres worldwide). Throughout Europe there are more than 500,000 acres of protected agriculture. The U.S., however, ranks 11th among countries, with only around 20,000 acres of protected agriculture, according to 2010 figures.

That may change as growers here look at the experiences of those in other countries who are realizing significant benefits from covering their crops. Viramontes says there are different forms of protected agriculture, but they all share a common purpose: “They use technology to enhance nature, to protect the crop against the elements, and to manage the elements.”

In Mexico, tomatoes are the primary crop grown using protected agriculture technologies, but it’s also common to see bell peppers, cucumbers, eggplants and even papayas, berries and lettuce.

More difficult than selecting which crops to grow is the initial decision of which type of protected agriculture technologies to adopt. There is an array of choices, but not all make sense for every grower. “The decision about what technology to use is actually quite complex. There are so many different levels, from greenhouses to hybrids to shade houses, that there is no ‘one-size-fits-all’ solution,” Viramontes explains.

That’s because growers in different climates need to protect their crops from different elements. Viramontes likens it to packing for a vacation: If you’re going to a ski area, you wouldn’t pack a bathing suit; likewise, if you’re going to a beach you wouldn’t pack your snowsuit. “You have to select the right technology for the application,” he summarizes.

Another factor that impacts what type of protected agriculture technology to employ is the grower’s market objectives. “Are you aiming at high quality? Are you aiming at high volumes? Are you aiming at growing in hot weather or cold weather, high humidity or low humidity? The answers will determine what technology you will use,” says Viramontes.

For many years, greenhouses were described as “high-tech” and shade houses as “low-tech.” Viramontes says, “When you look at it, the technology involved in both is very high. In both cases, you’re using very efficient irrigation systems and very efficient methods of [weed and pest] control, and you’re using very intense methods to manage quality.”

He prefers to think of protected agriculture technologies as being either “active” or “passive.” The more dynamic the elements are to manage, the more active the technologies required, says Viramontes. In a greenhouse, that might mean heating or ventilation systems. If those technologies are not required, a more passive approach, such as sunscreens, shades or windows, might be sufficient. “One harsh reality about the market is that it doesn’t recognize the technology behind the product. If you’re developing a #1 tomato inside a shade house and a #1 tomato inside a greenhouse, you can’t charge $1 more for a tomato just because it came from a greenhouse,” he explains.

By using the right protected agriculture technology, costs can be reduced due to improved efficiency.

Viramontes notes that in Spain (the world’s second largest protected agriculture country), the technologies being used are mostly passive. “They have climate conditions that are very adequate for growing vegetables. But if you go to the Netherlands (number seven worldwide), you’re going to see the Star Wars of horticulture technology, because they don’t have the sunlight, the right temperature; basically, they don’t have any of the right conditions to develop a crop, so they have to manage way more elements.”

Active protected agriculture technologies allow growers to produce crops in conditions they otherwise may not be able to, and also within the optimum market window. The costs are high (sometimes more than $20 per square foot, Viramontes estimates), but the market to Germany and other nearby countries is a high-end market that bears those costs, he points out. Plus, Viramontes says that growers in the Netherlands have found that they can sell byproducts of the greenhouse operations (carbon dioxide or electricity) to help cover the costs of the infrastructure.

According to AMHPAC, agriculture installations in Mexico in 2009 cost an average of more than $70,000 per acre for infrastructure. “But we don’t see it as an option. Even though Mexico has one of the best climates for agriculture in the world, it’s very unpredictable,” says Viramontes. “Sometimes it rains, sometimes it doesn’t. Sometimes it gets cold, sometimes it gets hot. So, you need something to manage the elements.”

Growing in a protected environment allows for more efficient use of labor than in field growing, says Gene Giacomelli, director of The University of Arizona’s Controlled Environment Agriculture Center (CEAC). “The crops are more at their hand-the tomatoes are hanging there, the lettuce is sitting there. They don’t have to go find it,” he points out.

While the use of protected agriculture has been growing dramatically in that country, the acreage devoted to open-field vegetable production has been quickly declining, he notes. “I believe their cost structure doesn’t make sense. I don’t think they can be competitive in terms of trying to grow the same quality of products at the same price.” He feels that point is valid for open-field growers both in Mexico and the U.S.

The U.S. obviously lags behind many other countries in terms of protected agriculture acreage, but the rationale behind these technologies makes just as much sense here as elsewhere in the world, says Viramontes. “I really take my hat off to the greenhouse growers in the U.S. who are using highly efficient technologies. But for the vegetable industry as a whole, I do see a problem. I see a lot of growers who are not investing in more efficient, modern, high-tech methods of growing. They are still inefficient in irrigation, in pest control, in labor management, in land management,” says Viramontes.

He thinks part of the reason may be that many growers view their land in the future as real estate (a golf course or housing development) rather than as land for growing crops. “In the parts of the U.S. where the focus is agriculture, you see companies doing their homework and investing in technologies to be efficient and to maintain their competitiveness. The public wants better quality and they want to pay less, so we need technology for that.”

Viramontes says the thing that ties together those using protected agriculture is that they see growing as a business: “Many of the growers in Mexico who are making that leap are third-generation growers. Most of them are college-trained and have more business training. They understand the requirements of the market: high quality, clean products, food safety. Protected agriculture allows you to deliver these in a more efficient way.”

He adds that protected agriculture tends to attract more forward-thinking growers who often form networks to share knowledge and information about technologies and high-efficiency approaches. “A lot of people, when they think about growers, picture someone sitting on a tractor. But growers today are businessmen, and they have to be good businessmen. They’re worried about the same things any businessman worries about: efficiency, labor, markets,” says Viramontes.

It does require a change in mindset to switch from open-field growing to protected agriculture, he acknowledges. However, growers who make that transition are in a much better position to control variables while improving efficiency. “By being in a closed environment, of course you have more control over making your product clean and safe, and over your labor,” Viramontes says.

There are a number of resources growers can turn to for guidance on getting into protected agriculture (see sidebar for a few examples). One of the groups involved with this area is The University of Arizona’s Controlled Environment Agriculture Center (CEAC). “We do research, teaching and extension outreach focused on controlled environments to help solve the problems of crop production systems in greenhouses,” explains Gene Giacomelli, professor of agricultural and biosystems engineering and director of the CEAC.

Giacomelli says the major challenges in greenhouse growing are the same facing most every grower: energy, water, labor and marketing. Protected agriculture, he says, is actually designed to help overcome some of these hurdles: “For instance, you can use water more effectively than it’s used in open fields, because you can get more production per unit-area in a greenhouse, and also more production per unit-use of water. Labor can also be used more effectively, because you can work in a better climate in a greenhouse than you can in the field, particularly in the cold part of the winter and the hot summers.”

Not only are workers more productive in a more comfortable environment, but the nature of greenhouse growing helps them to work more efficiently. “The crops are more at their hand – the tomatoes are hanging there, the lettuce is sitting there – they don’t have to go find it,” Giacomelli points out. “Probably 95 percent of the heads of lettuce are harvestable. If you pick a head of lettuce, there’s a pretty good chance it’s going to be put in the box for sale, whereas in the field that’s not necessarily the case. That makes their actual labor more efficient.”

The first decision facing those interested in getting into protected agriculture is what type of system to use. “There are two fundamental parts of every greenhouse system. The first is the greenhouse itself – some structure to provide a certain level of control. You need to pick your greenhouse and decide how much money you’re going to put into it. That will determine how much control you’re going to get,” Giacomelli states.

High tunnels, for example, are simple structures that provide almost no environmental control and include no electric power at all for fans or heaters. On the other end of the spectrum, a fully controlled greenhouse might have heating and cooling, ventilation, shading and lighting systems incorporated. “These all add to the cost, but they have additional expected returns that might be eight or nine or 10 times greater on a yearly basis than the lowest cost structure,” he explains. It’s about “controlling the air around the plant,” emphasizes Giacomelli. “That’s what helps make the plant grow.”

On a more basic level there’s the decision on how to grow crops within that controlled environment. “The [decision about] rootzone environment is just as important, whether you’re providing hydroponics, where the roots are fully controlled in a water bath or flowing stream of water with nutrients always at optimum levels, or the more traditional method of putting the roots in the soil,” says Giacomelli. The latter offers less control, but is chosen by organic growers or those who simply have a desire to plant in the ground.

Between the choice of structure and root- zone environment, there are a variety of possible combinations. “Every grower does it a little differently,” he notes. “If someone asks me what they should do, I ask them, ‘What’s your experience? Are you an experienced soil grower or an experienced hydroponic grower?’ Because if you want to change [from one to the other], it’s best to do it slowly and practice for a year or more before you transition your greenhouse.”

Given the investment in the technology required, those growing in controlled environments need to produce better yields, a better product and one that, hopefully, can be sold for a premium, says Giacomelli. He feels the current focus among consumers on high-quality, pesticide-free, locally grown products has created a situation where protected agriculture is particularly well-suited to meet that demand. “You can provide consistent quality almost year-round in some cases,” he observes. Plus, the controls used are mainly biological rather than chemical.

These greenhouses in Mexico are one small part of a growing trend toward the use of protected agriculture in that country. The ultimate goal of protected agriculture is to enhance efficiency, sau Eric Viramontes, CEO of the Mexican Association of Protected Horticulture.

That doesn’t mean that protected agriculture is for everyone. An incompetent field grower will not be made suddenly competent by moving into a controlled environment. “You’ll fail just as quickly, if not quicker,” he emphasizes. As one example, says Giacomelli, if you observe a pest out in the field, you might have several days before applying controls. In the greenhouse, if you see a pest it must be controlled immediately. Plus, the financial stakes of failure will be even higher because of the cost of the technology involved.

A number of those who are getting into growing vegetables in controlled environments are coming from the floral industry and have a background in greenhouse growing, notes Giacomelli of a current trend. Traditionally in the U.S., greenhouse growers focused mainly on bedding plants and flowers. “That’s because people could make more money selling flowers than going through the added difficulties of growing vegetables,” he observes. “Well, that’s finally beginning to change. Floricultural production has leveled off in the U.S., and those greenhouse growers are just beginning to look to vegetables as an alternative.”

Whether it’s someone coming into protected agriculture with past greenhouse floral experience or prior experience growing vegetables outside, there is a learning curve, says Giacomelli. “If you are a good field grower, you won’t necessarily immediately be a good greenhouse grower – it’s a different world,” he explains. “Read a lot, search out short courses, talk to your local county agent and get all the information you can.”

Patrick White is a freelance writer based in Middlesex, Vt. He is always on the lookout for unusual stories and cutting-edge installations.


Here are a few organizations conducting research and offering guidance on protected agriculture technologies in the U.S.

The University of Arizona’s Controlled Environment Agriculture Center:

The University of Florida’s Protected Agriculture Project:

The University of Tennessee’s Pro-tected Agriculture Program:

National Greenhouse Manufacturers Association: