November 2000

The Generic Greenhouse–There’s No Such Thing By Linda Barnett

Generic greenhouses might meet some of the criteria of any given grower, but they likely would not meet most growers' needs regarding crops and growing styles, not to mention zoning, building code, elevation, and automation requirements.

The greenhouse purchase decision should not be driven by price because many greenhouse packages actually are more expensive than are custom houses. Nonetheless, one of the most common questions we receive is “What does a greenhouse cost?” Good question. But here's an even better question: “What would be the cost of a greenhouse that fits my specific needs?” The answer: individual needs vary due to local codes, the purpose for the greenhouse, geographical location and future expansion plans.

The simplest commercial greenhouse is referred to as a “cold frame.” Cold frames are designed for wintering-over crops and for shade. They are sometimes considered “temporary structures” and do not meet codes. The cold frame is about as standard as a growing structure comes, but significant variables can be found among them. For instance, growers can now opt for stronger cold frames; some are now available in structural strength tubing. If a grower plans on growing crops on the ground, sidewall height becomes an important consideration. Height is also important if any overhead equipment is to be hung from the structure.

At the next level, we encounter the “workhorse” greenhouses. These houses require permits and must be built to local building codes. They are not necessarily flashy, but they are designed to provide years of efficient, dependable crop protection. They have the added benefit of being compatible with environmental controls. These houses can stand alone or can be gutter-connected to form acres of production range.

Here's the deal with the top-of-the-line houses: Some growers proclaim them a godsend, while others proclaim them unduly costly. More often than not, growers who bemoan the expense of high-end greenhouses are those who embarked on ill-planned spending sprees to equip their new ranges.

In fact, these houses are available with equipment that can control any environment. Controls have become so sophisticated that a good grower can monitor activity and results in any given zone at any given time. The grower who properly researches the type of production technology and computer controls best suited to his or her situation can dramatically improve crop yield and quality at an impressive efficiency of cost.

Before committing to new construction or to an expansion, the grower also must consider future plans. The type of equipment specified and its placement is largely determined on whether the grower anticipates future expansion. Most houses can be lengthened or can accommodate side additions Ð assuming such modifications have been planned in advance.

If a rule of thumb is called for, I would suggest that it be, “Think flexibility.” Many growers integrate different types and styles of greenhouses in an effort to produce a diversity of crops throughout the year. In this type of situation, the site of the greenhouse is critical. Available light in summer and winter must be accounted for, as does seasonal temperature variance. Needless to say, the grower should also check into local zoning and codes.

Growers call us daily asking for greenhouse construction cost estimates. Our first question is, “Have you contacted the appropriate government regulators?” Any responsible greenhouse manufacturer will design and engineer greenhouses based on local government planning and zoning codes. A greenhouse should NEVER be designed before all necessary governmental authorities have been contacted. The first contact should be city hall or the local municipal building to get information on the code authority (definitely find out what year and what section are applied). This is also the time to apply for a building permit for the greenhouse. As manufacturers, we are particularly concerned with wind and snow load requirements where applicable.

Zoning is defined as any section or district in a city restricted by law for a particular use (i.e., homes, parks, and businesses). Zoning, as you probably know, is extremely location-oriented. For instance, in Santa Fe, N.M., a building can be no higher than the Cathedral Tower. In Washington, D.C., nothing can be higher than the Capitol Dome.

Growers should be particularly diligent about obtaining accurate zoning information in small towns and counties where municipal services may be operating under tight budgetary constraints. Zoning regulations may be outdated or even non-existent. Conversely, the zoning laws of some towns and counties may be intended to greatly restrict, even eliminate growth. Zoning laws are a very powerful and a politically effective way to restrict growth; don't count on local building inspectors to back down!

Zoning is unique to location. “Setback,” common in large cities, is the required distance from the street a building can be sited. For example, a building may be required to be sited no closer than 50 feet from the curb to preserve what city planners call “street appeal.”

Zoning requirements can even vary depending on the amount of trees on a lot or on bordering buildings. In some locations, code regulations might even be relaxed. This is known as an “agricultural reduction.” For example, a 25 percent agricultural reduction on a 20-pound wind load code would mean the greenhouse need only accommodate a 16-pound wind load.

The greenhouses sited in a particular area may fall under the same zoning requirements, but they won't necessarily fall under the same building requirements. For example, “Joe's Greenhouse” may need a small setback, allowing it to be built exactly the way the grower wants. Meanwhile, “Joan's Greenhouse,” just across the street, may require 50 feet of setback, consequently throwing a monkey wrench into Joan's desired plan.

Zoning also includes building materials. Government regulators can dictate exact specifications for such items as brick, coverings and glass. Beyond material specs, regulators also can dictate the overall look of the greenhouse under consideration. For instance, a retail greenhouse to be sited in a shopping district might have to meet certain aesthetic standards.

Another question to ask your code official: Is it required that a licensed engineer stamp the finished drawings? If so, an engineer licensed in that state must stamp the calculations and drawings .

Last, but certainly not least, what are the fire codes specific to your area? What category does a greenhouse fall under? Do greenhouses have a specific niche or do they fall under the fire codes applicable to general buildings?

Many growers have elaborate drawings made up only to discover that none of the fire codes have been addressed. Retail greenhouses often are required to have sprinkler systems even though greenhouse insurance companies do not offer a premium reduction for sprinkler system installation. Fire codes are becoming stricter, particularly for greenhouses that welcome the public. Nothing will bring your building to a halt faster than failure to meet a fire code.

While the United States recognizes 50 state governments, the number of local governments approaches six figures (87,000 at last count). But don't fret! Greenhouse manufacturers go to great lengths to assist growers in meeting all pertinent codes and ordinances. For instance, at Stuppy, if we kno

w what code and year a government authority is using, we can reference it.

Here are some suggestions on the sort of “legwork” you should accomplish before you call your greenhouse manufacturer.

•Check with your zoning authorities for the setbacks specific to your location, the building materials requirements, and allowed businesses.

•Talk with the planning commission regarding building codes. What code body has been adapted specific to what year? Are stamped licensed engineer drawings required? What are the wind and snow load requirements?

•Check with the fire authorities. What do they require for greenhouses, specifically sprinkler system and covering requirements?

Zoning, building and fire codes can be daunting to the point of almost overwhelming a grower, particularly a new grower. Needless to say, it's in the best interests of reputable greenhouse manufacturers to help growers navigate through the intricacies of code. Reputable manufacturers also are eager to help the grower tailor a greenhouse design around what the grower produces and how the grower produces it.

Now if you ask for my opinion of a manufacturer who claims that you'll do just fine with a generic greenhouse package, all I can suggest is that you immediately contact another manufacturer. After all, do you really believe you are a generic grower?