Small Mechanical Harvester for Edamame and Green Bean Production

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2013: $7,481.90
Projected End Date: 12/31/2015
Grant Recipient: Mary Ellen Raymond farm
Region: North Central
State: Missouri
Project Coordinator:

Annual Reports


  • Vegetables: beans, lentils


  • Education and Training: on-farm/ranch research
  • Production Systems: general crop production

    Proposal summary:

    Most edamame in the United States is imported for the frozen food market. Local US production for the fresh food market is growing, but is limited by harvest methods. Edamame can be harvested with a mechanical green bean picker, but commercially available bean pickers are not economically viable for use on small farms.  A used Oxbo pull-type bean picker can cost $20,000 and is approximately 16 feet long, making it too large and cumbersome to use on a small farm, as well as too expensive. Picking edamame and bush type green beans by hand is very laborious, not cost effective and not sustainable. Although demand is high and prices can be fairly good for edamame ($8/lb at farmer’s markets), the selling price does not support the cost of harvest labor. This is unfortunate because edamame is very popular amongst children and is an excellent healthy substitute for snack foods, such as chips. Making edamame and bean production more feasible and productive for small growers will help raise farm incomes, keep small farmers in business, produce locally available vegetables and provide healthy foods to consumers.


    To provide the ability to mechanically harvest edamame and bush beans, Ethan Marshall designed a new bean picker for small farmers. The design is compact, relatively easy to build and easy to operate (diagram below). The cost of materials for the bean picker is $6915. Because this is a prototype, costs are expected to be higher for this model than subsequent ones because this construction will involve design testing as well as design modifications during construction. Ideally, the cost of a picker will eventually be below $5000. During this project, we will explore ways to get costs below that level. The picker is approximately 6 feet long (not including tongue) and hydraulically operated. It can be made to be PTO-driven, driven by tractor hydraulics, or driven by its own motor. The reel is designed to finger through the plants, pulling both the beans and the leaves onto the conveyor belt. The conveyor assembly uses two 12-inch ribbed belts and carries the beans from the reel, under the fan, and finally to sacks or a small wagon pulled behind the harvester. The wheels are adjustable so the user can move the conveyor closer or farther away from the ground. The fan is driven by a hydraulic motor and a belt. The fans blades are pitched steeply to cause more vacuum at lower speeds and the hydraulic motor allows the user to adjust the fan speed so beans are not lost through the fan and chaff is effectively removed.


    For this SARE project, Ethan will build the edamame harvester and Ethan and Mary Ellen will test it on Ethan’s farm in 2013, and will do season-long harvest studies with it on Mary Ellen’s farm in 2014. Mary Ellen will plant duplicate plots of edamame and harvest half with the mechanical harvester and half by hand for certain harvest dates. The amounts harvested and the profitability will be compared for each harvest method. Even though it is hypothesized that larger amounts can be harvested with the mechanical harvester, it is not known if damaged pods and harvest waste from the mechanical harvester will adversely affect economic gain. In hand harvest, immature pods can be left for later picking, maximizing the yield capacity of each plant. In mechanical harvest, plants are destroyed and all pods are picked in a single pass. Yields may decrease from culling of undesirable pods.


    This project will benefit more farmers than just Ethan and Mary Ellen because designs and construction plans will be made available via the internet and extension activities. Because small grower’s needs are often overlooked, equipment manufacturers that have been approached have expressed that they will likely not try to produce and market a small scale bean harvester in the future. Equipment is available for large growers, but there are no small-scale pickers available for the thousands of small producers that are struggling to make a living by selling for the fresh market. A lack of commercial interest spurs the need for farmer innovation and research into this problem that affects the viability and sustainability of small growers throughout the north central region. Harvest equipment needs to be designed and manufactured with small growers in mind since most fresh, local produce comes from small farms.

    Project objectives from proposal:

    Early Summer 2013- start building the edamame harvester when grant funds are released. This is estimated at 300 man hours so work will be done 20 hours/week for 15 weeks. If the project has progressed enough, some preliminary harvest testing may be done in the summer of 2013. We will video construction of the harvester and post videos on YouTube.


    August-September 2013- Begin testing edamame harvester to make sure equipment specs are matching crop requirements. Video field evaluation and post on YouTube


    October 2013 to January 2014. Finish construction of edamame harvester. Finish construction videos and post on YouTube.


    April 2014. Submit annual report to SARE


    July 2014. Make edamame harvester presentation at MU Organic Field Day, Columbia, MO


    July-September 2014. Conduct harvest tests with edamame harvester. Gather data on efficiency and changes in quantity and quality harvested with mechanical harvester over hand harvesting.


    October 2014. Submit article to Lincoln University Small Farm Program newsletter.


    January 2015. Present edamame harvester plans, videos and harvest results at Great Plains Vegetable Growers Conference (St. Jospeh, MO).


    February 2015. Make same presentation at Missouri Organic Growers Association Conference. Presentation will include agronomic and marketing information on edamame.


    March 2015. Make final report to SARE.

    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.