by Tiffany O’Neill and Hayden Bish, New Farmer Academy Interns
Have you ever wondered how Midwest farmers are able to produce tomatoes in the fall or grow greens in the dead of winter? High tunnel season extension is the not so small secret assisting local farmers with growing in the “shoulder” months of the year. New Farmer Academy interns Tiffany and Hayden recently had the privilege to assist Justin Husher at his farm, Old Hushers Indigenous Orchards, in constructing his new high tunnel. The interns have grown produce in high tunnels throughout their internship, but the process of building a tunnel was a new learning opportunity.
To begin the building process, Justin selected his site, the tunnel parts were delivered, and the crew was assembled. The first step of building a high tunnel was to pound in the base poles, which hold the structure together. Fortunately, upon delivery of the tunnel the crew installed the base posts and when the intern’s arrived the poles were in the ground, level and straight. These poles were the guide for the rest of the project.
The next step was to start constructing the arches. The arches are a crucial element to the high tunnel since they are the primary shape, therefore it was imperative they were measured correctly and constructed straight and sturdy. Nineteen arches were constructed in total, which took the majority of the day. After constructing the arches they were ready to be installed into the posts. It took all hands, two tall ladders, and many tools to raise the arches and line them up with the posts. Once a few arches were installed a rhythm was formed and the high tunnel started to take shape.
It took approximately five hours to get all nineteen arches installed and by the end of the day it was a work of art, and was ready for some food. The rest of the construction of the tunnel was slated for day two of the process.
Day two of the project was based around securing and strengthening the structure, to be able to withstand the Midwest seasons. A very important piece of a high tunnel, are the purlins. The purlins are metal rods that run parallel down the entire high tunnel that make the high tunnel more stable. The purlins were placed, using a template to ensure they were the same distance apart from one and another to evenly distribute the weight of the structure.
After the purlins were in place, the crew then moved on to installing the side plates for the wiggle wire. The side plates are a piece of flat metal that runs along, you guessed it, the side of the high tunnel. The side plates are made specifically to help hold the plastic and wiggle wire in place. The plastic goes on top of the plate, and the wiggle wire is then inserted to secure the plastic on the high tunnel. The side plates are very important and vital in the construction process.
Lastly, for day two the end walls of the high tunnel were constructed. The end walls were built using metal tubes prefabricated to accommodate the doors in the design. It is very important to measure correctly and level the end walls to ensure there are no cracks for air to escape. The end walls came together quickly, and the high tunnel was then ready for the plastic.
Unfortunately, Hayden and Tiffany were not able to assist in the plastic installation, but Justin was able to assemble a fresh crew for the plastic and he now has a completed high tunnel. High tunnel installation is a lot of work, but the reward of season extension is worth the effort in the Midwest agricultural community.