Low Tunnel

Structure

A low tunnel is a short row structure made with hoops covered by fabric or plastic. It creates a protected space over crops that is warmer and calmer than the surrounding garden. Many home gardeners use low tunnels to gain a few extra weeks in spring and fall.

How it works

The hoop shape holds the cover above the plants, which improves air space and reduces leaf contact with cold material. A plastic cover captures solar heat strongly during the day, while a fabric cover gives gentler protection with better airflow. The tunnel reduces wind, slows heat loss, and can raise both air and soil temperatures. Because the space is small, it responds quickly to sun and can heat up fast.

Best for

Low tunnels are well suited to salad greens, carrots, beets, onions, and young warm-season transplants. They are useful for early spring planting, late fall harvest protection, and short periods of harsh weather. Gardeners with long, narrow beds often find them especially practical.

How to use it

Set hoops at regular intervals over a planted bed and secure the cover tightly along both sides. Open the ends or lift the sides for ventilation on sunny days, especially when using plastic. Close the structure before cold evenings to hold in warmth. Monitor crops often so the tunnel supports growth rather than causing overheating or excess humidity.

Tips

Strong anchoring matters because tunnels catch wind easily. Plastic usually warms more than fabric but requires closer attention to venting. Repair small tears promptly so they do not spread.

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