Gardening With Leon High Tunnel

High tunnels, also called hoop houses or high hoops, are temporary structures that extend the growing season and can be used for a variety of vegetables, small fruits and flowers.

The structures are usually covered with one layer of plastic — in contrast to greenhouses, which use double-layered plastic or glass siding — and use solar heat. They are also a cheaper than most greenhouses.

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1Season extension
Increased temperature and cold protection are the most significant benefits to using high tunnels. Daytime temperatures are often 30-50 degrees warmer on a sunny day, rapidly increasing plant growth, and cold hardy crops can be harvested throughout the winter. Regardless of the region, high tunnels help growers produce crops outside the normal season.

2Climate
High tunnels provide protection from extreme weather such as high winds, heavy rain, hail, snow and drought. They also provide shade, protecting crops from heat and sunscald. Working in high tunnels allows the farmer to work/harvest in inclement weather.

Ventilation can be a challenge with high tunnels. Consider installing sides that can easily be rolled up during warm summer days to prevent your high tunnel from overheating. Also, consider small portable heaters for exceptionally cold days.

3Protection
High tunnels can help reduce pest, disease and weed pressures. Row covers used in the high tunnel can also help reduce the need for pesticides and/or labor, producing a higher quality crop. Insect screens installed along the sidewalls and doorways can exclude larger insects and mammals from entering the tunnel when sidewalls are up.

Some pests (mites, thrips and aphids) and diseases (powdery mildew) thrive in high tunnels and can easily get out of control. It's important to monitor crops and implement crop rotations to reduce the risk.

4Yields and income
A longer growing season, faster growth and higher productivity lead to higher quality, and higher marketable yield.

There may also be a better price premium for out-of-season crops and a potential for year-round income.

5Pollination
Some plants are self-fertile, however, pollinators can increase yields significantly. Pollinators will be able to enter the structure when fully opened, but they will not be able to enter if insect screens are being used. Planting a pollinator habitat, such as flowering cover crops, around the structure will attract them. Some larger operations may also incorporate bee hives.

6Irrigation
Since crops will not be exposed to rainfall, irrigation is essential. Initial installation of an irrigation system may be costly and irrigation may be difficult in the winter, due to frozen pipes or hoses. Consider placing a water hydrant/spigot inside the tunnel.

7Learning curve
Growing in a high tunnel requires a different set of skills, knowledge, management, tools, and equipment than field production. Fertility, irrigation (drip), pest management, cultivars, and spacing (including trellising) are often different from techniques used in the field.

Managing a high tunnel also requires intensive and vigilant attention: from structural maintenance to manual labor during the growing season, and time in the "off-season" if you plan to grow year-round.

Source: Introduction to High Tunnels, extension.org; Growing Under Cover, Kansas Rural Center; High Tunnel Production, University of Maryland Extension.

(Farm and Dairy is featuring a series of "101" columns throughout the year to help young and beginning farmers master farm living. From finances to management to machinery repair and animal care, farmers do it all.)