High Tunnel Gantry System with Transport Cart and Automated Row Cover System to Assist Small Farm Production, Scalability, and Profitability

Progress report for ONE21-381

Project Type: Partnership
Funds awarded in 2021: $29,944.00
Projected End Date: 03/31/2024
Grant Recipient: Rigorous
Region: Northeast
State: Vermont
Project Leader:
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Project Information

Project Objectives:

This project seeks to reduce repetitive and non-creative tasks through the use of an open-source High Tunnel Gantry System (HTGS) with two implements; a Transport Cart and Automated Row Cover System (ARCS).  

  1. Design.  We will develop a HTGS design plan.  The design will include the rail, toolbar, trolley car, Transport Cart, and ARCS.  We will engage farmers during the design process to inform the design and educate farms on design considerations.
  2. Build & Evaluate.  We will construct a fully functional HTGS.  We evaluate the implements for functionality, ease of construction, and ease of use. We will create videos of the installation and testing process to assist other farms adopting the system.
  3. Research. We will quantify the labor savings of the Transport Cart and ARCS through two labor studies. We will collect labor data during peak season and compare it to a similar control environment.  We will write a report detailing our findings.
  4. Education & Adoption. We will publish the designs, reports, and videos on our website and open-source tool design website, farmhack.org. We will host two on-farm workshops and publish demonstration videos.  We will present the research findings, use-cases, installation, and best practices at the 2022 NOFA-VT and NEFVC conferences.

Repetitive, laborious, and non-creative tasks hinder small farm profitability, scalability, and innovation. Labor costs are typically the largest expense for sustainable farms. Finding and keeping reliable help is increasingly challenging and hinders farms from sustainably scaling operations.

Farmers are increasingly growing in high tunnels in the Northeast. High tunnels help farmers extend their growing season, improve plant and soil quality, reduce nutrient loss, and reduce energy use (“High...”, (n.d.)). Since 2002, there has been a 3.5x increase in small vegetable production greenhouses (Tasgal, 2019). The Natural Resources Conservation Service (NRCS) has supported more than 9,825 high tunnels across the country since 2009 (“What…”, (n.d.)). 

Growing in high tunnels requires farmers to perform many repetitive tasks. Chris Callahan of UVM Extension conducted a survey of winter growers that found row cover management takes an average of 0.4 labor hours per day per 30x96’ tunnel (Callahan, attached letter, 2021). Assuming a $20 per hour wage and 120 day winter growing season, farmers pay $960 per tunnel per year. NOFA-VT conducted a cost of production analysis for high tunnel tomatoes. Harvesting greenhouse tomatoes accounts for 17.1 labor hours per 1000 ft2 (“Cost…”, 2019). Using the same 30x96’ tunnels, harvesting tomatoes accounts for 49.25 labor hours per tunnel or $985 per tunnel per year.

High tunnel gantry systems (HTGS) can reduce repetitive tasks and physical requirements while saving time and enabling innovation. Existing large-scale commercial greenhouses use advanced automation to improve profitability and scalability.  We are designing an affordable, accessible, and open source HTGS to allow small farms to benefit from similar innovation.  We will support education and adoption of the system through farmer design reviews, demonstrations, research, and presentations. 

The HTGS consists of one or more overhead rails, used as a monorail or together with a toolbar.  Like a tractor, the toolbar works with interchangeable implements.  A trolley car moves the implements along the rails to precise locations.  We will develop two implements; a Transport Cart and an Automated Row Cover System (ARCS).  

The Transport Cart saves farmers time and reduces the weight they must carry.  Andy Jones of ICF anecdotally found they saved 40% of labor time using a similar rail and cart system to harvest tomatoes.   Assuming $985 per tunnel per year for tomatoes, this equates to saving $394 per tunnel per year, not including time saved during transplanting, bed preparation and trellising. 

The ARCS removes the daily task of managing row cover.  We believe farmers can optimize the cover timing to increase ventilation, lighting, and temperatures for increased productivity and reduction of disease pressure.  Saving both row cover management labor and tomato harvest labor, farms can save an average of $1,354 per tunnel per year.

The HTGS represents an effort to reduce the health risks and labor costs of repetitive heavy tasks, while improving crop yield and overall quality of life for farmers. Advancements in technology can provide new jobs and space to innovate, exciting the next generation of tech-savvy farmers.


Click linked name(s) to expand/collapse or show everyone's info
  • Christa Alexander - Producer
  • Chris Callahan (Educator and Researcher)
  • Mark Fasching - Producer
  • Bob Lesnikoski - Producer
  • Aaron Loomis - Technical Advisor
  • Rebecca Maden - Producer


Materials and methods:

Objective 1 - Design 

We have conducted a rigorous engineering design through two phases - a preliminary design and a critical design.

As we conducted designs, we reached out for feedback from our target community. We worked with the members of our Farmer Design Review board, conducted one on one interviews with 5 regional farmers, and presented the idea to two greenhouse manufacturers. We learned that, while not ubiquitous, it is reasonable to expect high tunnels of winter growers to contain truss-style supports and extra tall sidewalls, both largely due to winter snow load and tomato trellising. In addition, we determined that it is reasonable to design this system to run on AC power and have access to a wifi network. We determined that the Transport Cart must be less that 55 pounds, fit standard bins, and have an easy on/off to move from rail to rail. 

Preliminary Design - sare_gantry_pdr_r03

At the preliminary design, we presented the concept and drafts of the mechanical, electrical and software designs. We broke the presentation into sections that explained each sub-system in detail such that the Farmer Design Review Board (FDRB) could provide feedback and critical direction.

Rail System - The rail system is made from SS20 fence toprail. This is an accessible product available throughout the country. The ends are swaged, meaning they fit together, and are secured by two screws. The rails hang from Railex brand C-bracket that are supported to the high tunnel crossbars with a U-bolt. We chose the 5.5" C-bracket to ensure ample room for the trolleys to pass between the top of the tail and the bottom of the bracket.

We presented our design for the Transport Cart. To keep the weight low, we modeled the cart out of aluminum. The review board noted that aluminum is challenging to weld and therefore would not be viable for most home fabrication efforts. They recommended we change to steel. Our original design fit a variety of harvest tote sizes, from bulk crates to bread trays. The review board recommended we keep the cart as narrow as possible rather than fit a wide variety of products. In addition, they recommended we change the frame supports such that farmers could easily load the cart from the front or back without reaching around the side.

The toolbar is a generic attachment point that connects the two rails and spans the width of the high tunnel. The toolbar was originally designed to hang from passive trolleys. We presented two styles - a fixed height model and an adjustable height model. To prioritize strength and simplicity, the review board recommended the fixed height. This model is adjustable at the time of the build, so could fit different high tunnels, but not adjustable once it is built.

The trolley car is a motorized box that drives the toolbar along the rail. We presented a concept that pushed and pulled the toolbar. The drive system comprises a NMEA 23 stepper motor and motor controller. We have geared this up almost 10x, bringing the total force to 27 newton meters, which we determined to be more than sufficient to push and pull the toolbar with implements.

The Automated Row Cover System (ARCS) is designed to spool and unspool row cover. It includes spooling motors at both sides of the roll and a frame that attaches the implement to the toolbar. The system also has a motor box and that motor box includes the same components as the trolley car. We estimated that we could spool a 28.5' roll of remay in the 30' house.

The concept of operations broke down the steps to set up and operate the system components, including through the user interface to the software.

Critical Design - sare_gantry_cdr_r01

In the Critical Design Review, we presented the updated and final designs, including the mechanical drawings. 

One major change was to the Transport Cart. We designed the frame to fit the dimensions requested and to be made from steel. The review board noted that aluminum would be preferable in some cases to increase potential load and that a modular/configurable cart would be ideal. They also noted that a subsequent iteration could include a support wheel underneath to further increase potential load. They noticed a design flaw where moisture could enter but otherwise approved of the changes.

We lengthened the toolbar to lower the entire system which is best able to maximize the larger width of the high tunnel at lower heights. The final height of the toolbar will be determined during assembly. 

The Trolley Car is no longer a free-hanging unit, but is now built directly into the toolbar. The weight of the toolbar and implement will provide better traction for the system. We designed a hitch that is made out of off-the-shelf springs and hardware and 3D printed parts. These attach to the Railex rolling trolleys and connect to the motor to create the drive system.

The major change to the ARCS was that we are now using self-aligned bearings. These will allow for sag in the spool.

We then discussed the materials cost and potential system issues for feedback. 

From the proposal:

Objective 1 - Design 

We will conduct a rigorous engineering design.  We will begin by collecting system requirements to generate a System Requirements Specification (SRS).  Stakeholders will include farmers, greenhouse manufacturers, and engineers.  Requirements will cover structure, environment, functionality, accessibility, and cost.  

Requirements will be created for the following system components:

Rail - Round tube hung from the high tunnel to allow hanging systems to move along the rail. 

Trolleys - Trolleys are passive rollers that allow you to hang and move items on the rail.

Toolbar - Generic attachment to connect various implements between trolleys.

Trolley Car - Motorized trolley that moves along the rail to move implements.

Transport Cart - Hanging cart used to move objects.

Automated Row Cover System (ARCS)  - Implement designed to automatically roll and unroll row cover.  

We will create a preliminary design and host a Preliminary Design Review (PDR).  The design will include Bill of Materials (BOM), mechanical drawings, and electrical drawings.  We will create a high-level design document that describes the system goals, the concept of operations (CONOPS), and system functionality.  The PDR will be reviewed by our Farmer Design Review Board. Feedback from the PDR will be incorporated into a final design.  The Farmer Design Review Board will review the final designs.

We will write a Site Acceptance Test (SAT).  The SAT will detail a set of tests and evaluations to ensure the overall system and subsystems meet the SRS requirements.  The SAT will include all procedures and tests to prove full system functionality.

Objective 2 - Build & Evaluate

We will construct an operational High Tunnel Gantry System (HTGS) for Jericho Settlers Farm, including both initial implements. We will build the system in a 100x30’ Ledgewood High Tunnel. The construction and testing process will be divided into phases for rail, toolbar, and implement. 

Rail Phase

We will make the rails from standard fence round tubing, Railex hangers, and Railex trolley wheels.  We will use two rails to span the 30’ greenhouse.  The rails will operate independently as a monorail or together as a system.  The rails are installed over the high tunnel’s walking rows such that the Transport Cart can be pushed down the rows without impeding the crops.  We will test the trolley system to ensure the system can carry designed loads and move smoothly over junctions.

Toolbar Phase

The toolbar will be made from off-the-shelf strut channel and extend 30’ across the high tunnel.  The toolbar will provide a standard interface for implements.  The toolbar hangs from both rails and two sets of trolleys horizontally across the high tunnel.  The toolbar will carry the ARCS.  We will test the toolbar’s capability to carry designed loads, move smoothly down the rail, and support multiple implement types.

Implement Phase

The Transport Cart will be made from welded standard square tube and rail trolleys.  We will test whether the Transport Cart can carry the designed loads, move standard-sized harvest bins and greenhouse trays, and smoothly move down the rails.

The Trolley Cars will be made from 3D printed parts, motor, motor controller, drive wheels, sprocket, and chain.  The trolley car will include an embedded computer with a camera to autonomously control the trolley.  The computer will run existing Rigorous software to autonomously control the system. This software is not open source. The embedded computer will control the trolley’s positioning and collect photographic data.  The photographic data will be used for system positioning, verification of tasking, and plant data collection. We will test the Trolley Car’s ability to pull the specified load, positioning accuracy, and data management system. 

The ARCS will be made from standard round tube, bearings, spooling motors, sprockets, and chains.  The row cover system will span the 30’ width of the greenhouse and hang from the toolbar.  The ARCS will include two motorized trolley cars to move the hanging implement down the rail.  As the trolley cars move the ARCS, the on-board spooling motors will roll/unroll the row cover onto a spool.  We will test the ARCS’ ability to effectively roll and unroll the row cover, the trolley car’s ability to move the ARCS, the system's ability to synchronize the two trolleys with rolling motors, and the system's ease of use.  

We will document and release instructions and videos of the process.  Upon completion of all build phases, we will conduct a Site Acceptance Test (SAT).  The SAT will verify all SRS requirements have been satisfied and the system is ready for the research objective.

Objective 3 - Research

The research objective will quantify the effectiveness of the HTGS by performing a labor analysis. 

The labor analysis will specifically look into how the Transport Cart and ARCS reduce labor and physical requirements.  We will quantify the reduction of time and physical requirements for both implements.  

We will run the HTGS and ARCS for thirty concurrent days at Jericho Settlers Farm. We will set up a comparably sized control house with similar plants and planting dates. Christa Alexander will record the time spent moving row cover in the control house every day and time spent in the test house with the HTGS. We will write a report comparing the labor required with and without the ARCS.

For the Transport Cart, we will host our test and control beds in the same high tunnel. Two beds with tomatoes will be on both sides of a single rail of the HTGS with the Transport cart. In the same tunnel, two beds with the same varieties of tomatoes will be on both sides of an open walkway. For two months during peak harvest and trellising, we will track data to compare labor time and harvest weights for the test and control beds. Jericho Settlers Farm will time sessions with and without the trolley. This will likely be 20 to 24 harvest sessions and 10 pruning sessions. 

We will analyze the results and prepare a summary report that we will make publicly available. We will calculate total seasonal labor savings estimates based on these trials. We will also quantify the reduction of carried weight, calculated by collecting harvest data weight data over the average distance of travel.

Objective 4 - Education & Adoption. 

We will create a PDF instructional guide linked on farmhack.org but downloadable free of charge from the Rigorous website. We will host plans, designs, and instructional content online. Instructional content will be created during all phases of this project and will cover best practices for installation, testing, and use. The content will be in a variety of formats, including video and written articles.

We will host two on-farm workshops where we will demonstrate the system. We will record the sessions for farmers to view online. We will cover the installation, load constraints, and best practices of the system. Through these workshops, participants can test drive the implements and ask questions directly. 

To measure achievement of this project, we will track the following metrics.

To quantify education:

  1. Number of design downloads
  2. Supporting materials content views
  3. Attendees of demonstrations

To quantify adoption and farmer benefit:

  1. Number of new systems installed
  2. Labor hours saved as reported by farm partners
  3. Reduction of carried weight, calculated by collecting harvest weight data over average distance of travel
Participation Summary
9 Farmers participating in research

Education & Outreach Activities and Participation Summary

4 Consultations
3 Curricula, factsheets or educational tools
2 Webinars / talks / presentations

Participation Summary:

9 Farmers
3 Number of agricultural educator or service providers reached through education and outreach activities
Education/outreach description:

We have begun one on one interviews to determine feasibility and desirability of the High Tunnel Gantry system. We toured and interviewed Mira and Dakota Miller of Row by Row Farm (Hurley, NY), Tony and Joie Lehouiller of Foote Brook Farm (Johnson, VT), and Paul and Sandy Arnold of Pleasant Valley Farm (Argyle, NY). We also received general feedback from farmers at Intervale Community Farm (Burlington, VT) and Ardeen Farm (East Aurora, NY). 

We looked to understand current season extension activities, barriers to winter production or expansion, infrastructure, and use of new or unconventional technologies. 

We hosted a preliminary design review and a critical design review for the Farmer Design Review Board which has set us up to construct the system in January 2022. We will test the system for about one month and will then schedule an on-farm workshop and demonstration that is open to the public.

We have started to post regularly to our Instagram account. This includes the creation of graphics from our design files. We have posted designs for feedback as well as shorts of us constructing components of the system (images below) and recaps of farm tours. While this project is not the only thing we post about on the @rigoroustech account, we have reached 10.7K accounts in the last 90 days. We have 190 followers, the majority of which are farm or food system-based accounts. Project-related posts have reached up to 627 accounts each with up to 41 likes and 12 comments. We regularly receive a handful answers to posed questions, mostly asking about growing practices and soliciting design feedback.

We hope to leverage this channel to drive awareness to the workshops and digital resources. We wrote a blog that summarizes the project and plan to continue to write blogs and tutorials. https://www.rigorous.co/blog 

From the Proposal:

We will engage and educate farmers throughout the design, build, research and adoption objectives. We will solicit input from farmers to inform the design of the High Tunnel Gantry System (HTGS). We will create materials and host workshops to teach farmers how to build the HTGS and corresponding implements. We will research and share results to educate farmers about the benefits of this technology. We will present the findings of that research as well as best practices for use and installation online and at regional conferences.

We will communicate with at least twenty regional farmers about the potential need and desired functionality of the HTGS.

The farm advisory board will convene two times for a review of the HTGS design. The first will be the Preliminary Design Review (PDR). The board will review and suggest modifications to the HTGS, Transport Cart and ARCS designs. The PDR will be recorded to create a video for additional farmer outreach and input. Once designs are complete, the board will attend a final design review. 

We will publish design instructions for the HTGS, Transport Cart, and ARCS. We will offer unlimited access to the designs and publish links and descriptions to the open-source tool website farmhack.org. 

We will continue to communicate with farmers through one-on-one conversations with a goal of understanding and remediating barriers to adopting the system.

We will create video demonstrations of different stages of the design, installation, and use of the HTGS. These videos will be hosted on the Rigorous website, youtube, and social media, with links to build instructions and a bill of materials. We will share updates with regional organizations and listservs, including the Vermont Veg and Berry Listserv. We will track the number of design downloads and content views of supporting materials to measure the impact of this project.

We will lead two on-farm workshops with Jericho Settlers Farm. The first will be a demonstration of the ARCS, discussion of best practices, and review of the ARCS labor study results. The second workshop will demonstrate the Transport Cart. We will discuss best practices and results of the Transport Cart labor study. We will record both workshops and post the videos online. These recordings will be included with other support materials alongside the design instructions on the Rigorous website.

We will present the findings of our tool development and labor study at agricultural conferences. We will apply to present at the National Organic Farm Association of Vermont’s winter conference and the New England Fruit and Vegetable conference in 2022. Our presentations will cover the process for designing, building, and researching the HTGS, Transport Cart and ARCS. We will cover lessons learned along the way and best practices. We will review the labor studies and seasonal labor savings based on our testing.

Learning Outcomes

12 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key areas in which farmers reported changes in knowledge, attitude, skills and/or awareness:

Thus far, we have shared detailed information with our collaborators (4 farmers) and the farmers we have had one on one interviews with (8 farmers, 4 farms). These farmers now have a deep understanding of the system we seek to build and have been able to provide critical feedback to influence the designs. They have also been able to conceive of additional ideas for the high tunnel gantry, displaying understanding of its potential in their operations.

In addition, we have reached 627 Instagram accounts with one post about the automated row cover system alone. It is difficult to quantify how many farmers are in that group, but we will be able to better track farmer engagement once we have materials available for download, as we will be collecting basic information. 

Project Outcomes

1 Grant applied for that built upon this project
1 Grant received that built upon this project
Project outcomes:

Not Yet Available.

Assessment of Project Approach and Areas of Further Study:

Not Yet Available.

Information Products

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.