Hoop House (High Tunnel)

Structure

A hoop house, often called a high tunnel, is a larger unheated structure covered with clear plastic. It allows gardeners to grow crops in a more controlled environment than the open field. Compared with small covers, it provides more working space and longer season extension.

How it works

The plastic covering admits sunlight and traps heat, raising daytime air and soil temperatures inside the structure. The cover also shields crops from wind, frost, and rainfall, which helps reduce weather stress. Heat stored in the soil and inside materials can moderate overnight cooling, though temperatures still drop without added heat. Ventilation is essential because high tunnels can become very hot and humid on sunny days.

Best for

High tunnels are useful for spring and fall vegetable production, winter harvest in milder climates, and summer crops that benefit from rain protection. Tomatoes, cucumbers, peppers, greens, and herbs are common choices. They are best for gardeners who want a more durable season-extension system and can manage ventilation regularly.

How to use it

Choose a level, sunny site with good drainage and enough room for air movement around the structure. Prepare beds inside before planting and plan access for watering, weeding, and harvest. Open doors, sidewalls, or vents as temperatures rise, and close them before cool nights when protection is needed. Rotate crops and manage irrigation carefully because natural rainfall does not reach the soil inside.

Tips

Track both daytime heat and nighttime lows, not just one or the other. Good airflow helps reduce disease pressure from excess humidity. Snow, wind, and summer heat loads should be considered when choosing and maintaining the structure.

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General guidance for US gardens. Pair with your local frost dates and hardiness zone. Page updated Aug 4, 2026.