Mar 26, 2019Nifty Hoops shares considerations for hoophouse selection
The flexible design of hoophouses gives growers many choices. They must select a site, choose a design – probably Gothic Arch or Quonset, decide on the type of ventilation, endwall and fabric, and prepare for the installation.
An east-west siting is preferred for hoophouses, but is not as important as selecting a location exposed to full sunlight.
“Look around for potential shade,” said Phil Irwin, installations manager of Nifty Hoops, a hoophouse supplier from Ann Arbor, Michigan. Irwin was a speaker at the recent Great Lakes Fruit, Vegetable & Farm Market EXPO in Grand Rapids, Michigan. The hoophouse should be twice as far away as it is tall from trees and other hazards that could fall on the structure.
“These are a major investment,” Irwin said. “You don’t want a tree branch to fall and have to call us six months after installation to get your hoophouse re-covered.”
The site must be level. A clay soil is preferred because it will hold the posts the most securely. “The key to any good hoophouse is a good foundation,” Irwin said. Earth anchors can be added to compensate for other soil types.
Growers are asked to rototill the hoophouse site before installation to ensure evenness, Irwin said. This ensures the best installation of the baseboard.
A Gothic Arch is the design most growers should consider first in a northern climate like Michigan. “A Gothic Arch is very durable,” Irwin said. Its ability to withstand inclement weather comes from its sharp peak and sloping sides. The walls slope in from the sides making a gradual curve that peaks at the roof.
Proper positioning of the plastic is key to a Gothic Arch’s weather resilience. Pulling the roof plastic tight creates a hard ridge across the top, which keeps the snow or rain moving off the hoophouse.
“If you don’t have plastic tightness, water puddles and snow build-up is possible,” Irwin said.
A Gothic Arch also has more overhead space for tall plants like tomatoes that need trellising.
A hoophouse with a Quonset design isn’t as big as a Gothic Arch. “It’s smaller and doesn’t take up the huge space of a Gothic design,” Irwin said. It has a sloping roof and lacks the sharp peak of a Gothic Arch.
A Quonset better fits smaller growers or growers in urban environments. It’s adaptable and fits a caterpillar design. This design allows growers to expand their hoophouse in sections.
A caterpillar style is also mobile. “Use it to start your transplants in the field and then move the hoophouse to the next location” Irwin said.
There are many endwall options for both Gothic Arch and Quonset designs.
There are doors for workers and doors for equipment in many sizes. There are roll up endwall options. Endwalls can be made from a number of different fabrics and plastics.
Ventilation is an important consideration. Nifty Hoops offers a 78-inch, roll up side curtain that can be automated or manually operated by a hand crank. Hand cranks can be difficult to operate on large hoophouses.
“With 200 feet of hoophouse, that side curtain gets heavy,” Irwin said.
Nifty Hoops also offers a 48-inch louver vent mounted to the endwall operated with DC power. “DC only uses power when opening and closing doors,” Irwin said. “An AC unit draws power all of the time.”
When automated, both the roll up side curtain and the louver vent can both be operated by thermostat.
“Controlling them with thermostats means growers don’t have to live in the hoophouse watching the thermometer,” Irwin said.
Other ventilation options in the industry include tube vents, gable vents and drop down curtains – often used in combinations.
There are many types of covering used on hoophouses. The covering can be clear or white (opaque) and treated or untreated. Ultraviolet light (UV) resistance, infrared blocking and anticondensation properties are some of the common treatments available.
A trial run may be the best way for growers to see what works for them. “See if you can grow what you want to grow under plastic,” Irwin said.
The first step may be simpler for other growers. “Maybe you’re starting out and all you know is you want to grow under plastic,” Irwin said.
— Dean Peterson, FGN correspondent