Automated Row Cover System for Winter Greens Production
Updated: Aug 16, 2021
Last winter, Colin and I spoke with Mark and Christa of Jericho Settlers Farm about incorporating automation onto sustainable farms. They are a great team to dream up new tools with. They are early adopters of farm techniques and technologies including computerized greenhouse controllers and in-ground biomass-driven heat systems. In addition, they take great care to track data and use that data to inform their decision-making. So what would they automate if they could?
Remay. Specifically, row cover on winter greens.
Today, the JSF team produces organic vegetables year-round in 19 high tunnels.
"During the winter these houses are full of salad greens, which require almost daily uncovering and recovering with remay to protect the crops at night while giving them light and ventilation during the day. The task of moving remay in 19 structures is cold, repetitive, and demanding", said Christa.
If you've moved remay on a chilly morning, you may remember finishing the task wet and annoyed – I sure do.
Chris Callahan of the University of Vermont Extension conducted a survey of growers regarding high tunnels are row cover.
"Among the 46 respondents to this survey, the mean average of labor dedicated to managing row cover was 0.4 person hours per day per 30' x 96' tunnel."
A grower with 10 high tunnels is theoretically spending 4 hours per day moving fabric. It's no surprise that many farmers say things Ryan of Evening Song Farm said at the NOFA-VT 2021 Winter Conference:
"I often feel like I have more important things to do than take row cover on and off... we might grow better greens and have less disease pressure if we uncovered more often during the day."
Mark had shown us a prototype that he designed to mechanically roll and unroll remay with Robert Arnold of Smart Farm Innovations, a company in Upstate New York that designs and installs remote monitoring systems. We also found examples of remay rollers on the internet, including Ahavah Farm's manual crank and Clay Bottom Farm's ultra-low tunnel.
We considered a number of design options. Should the row cover be spooled at the end and unrolled down the house? That was our original best idea, but we needed to ensure the row cover wouldn't get dragged over the plants. We could have solved this with hoops or tracks, but also found that the lateral force (or more specifically, tractive force) required to unspool the row cover from above would cause the trolley wheels to slip.
We decided instead to hang the roll from the implement, slowly rotating as it moves up and down the length of the high tunnel.
We started prototyping the Automated Row Cover System in the winter of 2020/21. The system comprises:
Two overhead rails
Two motorized trolley cars
One toolbar that spans the width of the high tunnel
One row cover implement with two rotating motors on either end of the spool
This prototype did not include a mechanical toolbar; we practiced rolling and unrolling the spool by hand. We did create a computer-controlled working trolley that pulled the row cover implement up and down the track.
The original idea for the rail was to use unistrut because it is strong, inexpensive, and widely available. Unistrut is the material that supports industrial light fixtures and barn doors. There are two reasons why we are redesigning the trolley system to work on fence top rail rather than unistrut.
Farmers are already using rail systems made from fence top rail. We want this system to work with existing rail systems, plus there are hangers that can be purchased for exactly this purpose.
The ends of unistrut pieces are not uniform. To allow the trolley wheels to pass smoothly from one piece to the next, we would have to fabricate an insert or file them down individually.
We are designing this system with the support of a Northeast SARE grant (ONE21-381), in partnership with Jericho Settlers Farm. We are openly soliciting input and feedback. Got any? Email firstname.lastname@example.org. We'll find a time that works for you!