Diversify!

Your accountant tells you to diversify your portfolio; your business consultant tells you to diversify your inventory. With businesses running lean and mean these days, is it too much of a risk to launch a new product? Or is it risky not to?

You grow what you grow because you’re good at it, and because there’s a market for it. But it might be time to try your hand at something a little different — perhaps you’ve wanted to take advantage of the upswing in edible plant sales.

Starting small and testing the waters can be made that much easier if you’ve got the infrastructure to spare. No room in the greenhouse? Then try a high tunnel or two. Yes, many of these are the hoop houses familiar to growers, but today’s high tunnel structures have been redesigned for ease of construction and expandability. They’re flexible, they’re configurable, they’re sturdy. So, should you invest?

Let’s take a look at some of the advantages and disadvantages.

What is it?

First, let’s consider what a high tunnel really is. Very similar to a standard greenhouse in appearance — at least at first glance — a high tunnel differs from a permanent greenhouse in many ways.

High tunnels are passively heated and ventilated, plastic-covered structures. In terms of environmental protection and control, they stand squarely between open field and managed greenhouse. Versus a standard greenhouse, a high tunnel:

  • is generally a simple, low-cost structure;
  • employs one layer of plastic, providing a relatively low R-value;
  • is used to extend production seasons;
  • generally involves inground production;
  • requires low operating costs; and
  • depending on design and property, may not require site leveling.

You know: A hoop house.

When compared to field production, high tunnels provide many of the same advantages as a greenhouse. They can:

  • extend the season and can provide off-season production capabilities;
  • offer greater control of water application and reduce the risk of disease potential by protecting crops from rainfall and ambient moisture;
  • increase growth rates and production by providing more even light distribution and increased heat retention (thus reducing plant stress); and
  • prevent infestation by insect and animal pests.
  • sun exposure (is the site in full sun, with six or more hours of direct sunlight per day? Are there other structures or large trees that might provide shade?);
  • soil structure and quality (could the soil normally be used for field production? Is it rocky, or are there other obstructions that may prevent adequate anchorage?);
  • slope (will runoff be a problem?);
  • access to water for irrigation; and
  • basic location (is the site easily
    accessed by staff and equipment?).

ROI

Consider the cost. Compared to the cost of a permanent greenhouse — that is, unless you’ve already got greenhouse space available — the initial investment and continuing operational costs are minimal. The typical high tunnel structure does not include the mechanical systems, such as heaters, fans, lights and so on, required in a standard greenhouse.

And if you have the space available and you’re willing to devote unprotected, inground acreage to your crop, this section is moot. But understanding that a high tunnel can provide several more production turnarounds per year than can exposed plots, it’s worth a look at the dollars-in and dollars-out.

According to the University of Vermont, a permanent structure (considered a four-season high tunnel, hoop house or passive solar greenhouse) can cost about $2 to $3 per square foot. Say you’re erecting a simple, 24-foot-wide by 96-foot-long configuration; the cost would be slightly south of $7,000. These estimates are for conventional, single-bay construction; costs vary, of course, if multiple bays are required.

A three-season high tunnel generally costs $0.75 to $1.25 per square foot.

This does not include labor, nor does it include such equipment as benches and irrigation. However, because most high tunnel structures are employed for inground planting, many of the normal greenhouse accoutrements are unnecessary. Costs will vary depending on region, configuration and the quality of materials employed.

If you’re considering purchasing a kit, costs can range from $0.69 to nearly $6.00 per square foot. According to a survey by the University of Arkansas, you can spend as little as $3,000 for a simple, 480-square-foot round style structure and as much as $75,000 for a 110,000-square-foot, multibay premium building. But do you really want to go that far? What we’re talking about here is dipping our toes in to see if it’s worth a small investment.

SITE SELECTION

Your first consideration: Do you have the space? If so, be sure it’s sufficient for the size of structure you’re planning. A stationary tunnel will require, of course, a fixed location and is deemed to be long-term, but a movable tunnel can be relocated depending on changing production requirements or seasonal rotation considerations.

When selecting the site, consider the following:

  • direction of prevailing winds (does the site enjoy any sort of wind breaks? Is it exposed to seasonal blasts, such as Chinooks?);
  • sun exposure (is the site in full sun, with six or more hours of direct sunlight per day? Are there other structures or large trees that might provide shade?);
  • soil structure and quality (could the soil normally be used for field production? Is it rocky, or are there other obstructions that may prevent adequate anchorage?);
  • slope (will runoff be a problem?);
  • access to water for irrigation; and
  • basic location (is the site easily accessed by staff and equipment?).

DESIGN

Basic construction falls into two categories: Quonset (rounded) and Gothic (arched or peaked). Quonset (also called hoop house) tunnels are characterized by:

  • single bay construction;
  • rounded steel arches (generally 11- to 12-gauge steel);
  • arches that begin at ground level, giving the tunnel an overall rounded appearance; or
  • arches may be affixed to 4- to 6-foot-tall sidewalls, allowing room for taller crops

Gothic style tunnels are generally characterized by:

  • single bay construction
  • peaked roofs (think of a more modest Gothic cathedral; peaks help to manage snow loads);
  • taller construction than hoop houses, which may offer more stable temperatures; and
  • additional bracing may be required to handle winds.

From there, the options are many. Multibay structures allow for greater acreage in production and consist of several spans of arches or hoops connected by gutters at the roof seams; they may be built large enough to accommodate tractors and other large equipment. Single structures are… single structures.

Kits are available from a variety of sources, but do-it-yourself plans are also widely available.

A high tunnel structure can be easily constructed, reasonably priced and a good way to help you decide if an additional line of crops is in your future. A small investment now can lead to profits down the road. Are you willing to take the leap?

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