Winter Low Tunnel Protection Methods

Protection Methods

for OVERWINTERING in LOW TUNNELS

Johnny's Winter Growing Guide

Hoops, Covers, Ventilation & Temperature
Late winter greens
Transplanting greens for winter low tunnel production

Quick Hoops™ made of bent steel conduit or electrical metal tubing (EMT) are positioned over crops to be overwintered. We developed the Quick Hoops™ Low Tunnel Benders specifically for creating hoops that are strong enough to support heavy winter snow loads. We have found that hoops made of other materials, such as wire or PVC, fall short in this regard.

Using different bender styles, one can create 3-, 4-, or 6-feet-wide hoops for fabricating low tunnels that span one or two beds at at time. When frost is predicted, the hoops are covered initially with spun-bonded row cover (Agribon-19 or heavier) to extend the crop into the fall. These coverings protect the crop from frost, but allow them to respire and self-ventilate as temperatures fluctuate throughout the day.

After a few frosts have occurred and the likelihood of further warm days is minimal, a layer of 4-mil (100-micron) greenhouse film is added on top of the row cover. The edges of the covers are secured with sandbags, chain, or another form of weights placed placed along the edges of each hoop. If warm weather should occur after the addition of plastic, the low tunnels may need to be manually ventilated by lifting the sides, to prevent internal temperatures from getting too high. In the dead of winter, the tunnels will effectively be sealed shut by the snow load on top.

Following the winter solstice, the tunnels may again need to be vented intermittently, to prevent overheating as days grow longer and warmer. Once the danger of hard frost has passed, the plastic can be removed completely, with the row cover remaining in place to protect the crop until it is time for early-spring harvest.

Learn More

To learn more about How to Set Up and Manage Your Quick Hoops Low Tunnels, see our excerpt from Eliot Coleman's Winter Harvest Handbook.