Although the uninitiated may think that the work ends with the final harvest of the season, seasoned growers know better. Now is the time to repair everything that’s broken and to get things in order for a new season.
And for the days when spring weather doesn’t allow field repairs, work is the high tunnels can keep you warm, dry and productive.
Here are some high tunnel upgrades to consider.
Install a Temperature Alarm
This upgrade isn’t about improving efficiency as much as it is about protecting your tunnels from disaster. No matter what kind of ventilation and heating systems you use, failure is always a possibility. Propane heaters can run out of fuel and GFCI breakers can trip in the middle of a heat wave.
Thankfully, alarms can alert you if the temperature in your high tunnels goes above or below a certain threshold.
And, also thankfully, these alarms can be as cheap or expensive as you want them to be.
At one farm I worked on, we wired some batteries to a megaphone and an analog thermometer. The whole setup cost maybe $30. At the other extreme, you can purchase wifi-based systems that send alerts to your phone.
Either way, some sort of alarm will give you the peace of mind of knowing that you’re not one oversight away from losing an entire crop.
Get Roll-Up Sides
For growers without electricity in their high tunnels, roll-up sides are a necessity. Coupled with some gable vents, they should give your tunnel all of the ventilation it needs, even in the hottest months.
Even for growers with the luxury of electricity, roll-up sides offer some real advantages. They:
- require no electricity
- don’t come with any of the noise of an exhaust fan
- allow for a pleasant cross breeze that makes working in the tunnels a pleasure
In case you’re not excited about manually rolling the sides up and down, however, you can install motors to do the work for you. You can also hook these motors up to a thermostat so that they open and close at set temperatures.
Upgrade Your Endwall Material
For those doing any sort of season-extension growing in their tunnels, improving insulation is well worth the effort. One of the best ways to improve your tunnel’s energy efficiency is to upgrade your endwall material to something with a higher insulation rating.
Corrugated or double-layer polycarbonate works well on sides that you want to allow light in from. For north-facing (or already-shaded end-walls), consider paneling the outside of the wall with boards and hanging some sort of rigid insulation on the inside.
Your propane bill will never be the same again.
Put in Perimeter Insulation
If you’re interested in further improving your tunnel’s insulation (and not afraid of a little digging), consider insulating the perimeter of your high tunnel. The job entails placing foam board 2 feet down around the outside of your tunnel.
It’s not a job for the faint of heart but also won’t take as long as you think. The boards will mitigate heat loss to the outside and will retain your soil’s warmth well into the shoulder seasons.
No matter which upgrades you choose to tackle this winter, take advantage of your tunnel’s balmy winter temperatures to make them function a bit better next season.