Winter High Tunnel Survival: Snow, Ice, and Extreme Cold Tips for Growers

Winter weather can be hard on high tunnels, but a little preparation (and vigilance) can go a long way toward protecting both your structures and your crops. Here are some tried-and-true tips for managing snow load and keeping plants alive during extreme cold.

Managing Snow and Ice on High Tunnels

One of the biggest causes of tunnel collapse is plastic sagging between the purlins. Snow itself isn’t usually the issue—it’s what happens when the plastic stretches and creates low spots where snow and ice can collect.

• Keep plastic tight. If your tunnel has an inflation blower, keep it running during storms to help shed snow and resist sagging.
• Act quickly if sagging starts. From inside the tunnel, use a large shop broom to push up on the plastic and dislodge snow or ice. For taller gothic tunnels, an extendable painter’s pole with a tennis ball or snow broom attached works well—just be careful not to puncture the plastic.
• Clear from the outside when needed. A snow broom can pull snow down from the peak, and light snow can sometimes be blown off with a leaf blower. In a pinch, tossing a rope over the tunnel and walking it down the length (with a partner) can help shake snow loose.

If precipitation is coming down as ice or heavy, wet snow, consider adding temporary interior props or cross bracesfor extra support. During major storms, it’s worth setting an alarm to check tunnels overnight—much better than waking up to a collapse and flattened crops.

You’ll often hear experienced growers advise against shoveling snow away from the outside of tunnels until it reaches the hip board. That’s generally good guidance, but snow type matters. Four feet of fluffy snow weighs far less than four feet of wet snow or ice. Keep an eye out for wall bowing and pull snow back if pressure builds.

For perspective: snow with a 1-inch rainwater equivalent can load a greenhouse with 5.2 pounds per square foot, adding up to 6.5 tons on a 25' × 96' structure (UMass Extension).

One last reminder—turn off automatic roll-up sides before storms hit. Roll-ups opening under snow can shred plastic and dump snow directly onto crops (ask me how I know).

Protecting Crops During Extreme Cold

Once the tunnel is secure, it’s all about heat management.

• Water before a freeze. Moist soil holds and re-releases heat, helping buffer temperatures right around plant roots.
• Add extra frost protection. Two layers of frost fabric are standard during cold snaps, and three layers may be needed for sensitive crops. If the sun comes out, monitor tunnel temperatures closely since sidewalls will likely stay closed.
• Close up and cover early. Closing tunnels and covering crops about an hour earlier than normal helps trap daytime heat and carry plants through long, cold nights.

Winter growing is never hands-off, but staying proactive during snow and cold events can save structures, crops, and a whole lot of stress. Stay warm out there—and keep an eye on those tunnels.

AI usage note: Alexis Sheffield wrote this article, then used ChatGPT to adjust to an appropriate reading level.