Sweet Potatoes and Their Vines: A nutritional and sustainable alternative for food and livestock feed

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2019: $9,926.00
Projected End Date: 03/14/2021
Grant Recipient: farmer
Region: Southern
State: Florida
Principal Investigator:


  • Agronomic: potatoes


  • Animal Production: feed/forage
  • Crop Production: food processing

    Proposal summary:

    Potato farming has been the staple for Putnam County (FL) growers over the last century. However, in recent years there has been a significant decline in the potato chip industry because of genetic modifications and longer shelf life of potatoes grown in the Midwest. Additionally, the seed producers are located mainly in the North and freight rates to ship seed potatoes from the North the South are no longer competitive with other parts of the country. My freight rate for seed potatoes has increased from $8/100lbs in 2017 to $10.50/100lbs in 2018. However, my contract prices has not increased at all over the last 5 years. Thus, the market for southern potatoes is continually declining. In order to maintain economic sustainability and competitiveness within the agricultural industry, alternative crops must be grown and marketed in this area. The target crops need to be specifically suited for the warm, tropical weather in Florida to alleviate competition from the Midwest growers.

    The decline of the chipping potato market in the South is affecting many growers in the Tri-County agriculture area, which includes St. Johns, Putnam and Flagler Counties. Although my contract price has remained constant over the last 5 years, all my input costs such as fertilizer, pesticides, and freight rates have increased dramatically. I can clearly see the writing on the wall. For me to remain economically sustainable, I must be willing to branch out into an alternative crop and develop new markets. My background and experience are centered around growing chip potatoes and so this will require learning how to grow and market a totally different crop. I am one of the only African-American farmers in the TCAA and minority avenues for joining agricultural cooperatives and establishing new markets in the area are very limited.

    The project that I would like to propose is a science-based experiment involving an alternative crop that is suitable for the growing conditions in North Florida. Diversification is necessary to keep my farm economically and environmentally sustainable, especially for my next generation to have the opportunity to carry on our family business.

    Sweet potato is an alternative crop that offers nutritional advantages, versatility, and is easy to integrate into the potato chip cropping sequence. It is an attractive choice for us because the crop can be easily rotated with potatoes and the same equipment can be used for harvesting and grading both the potatoes and sweet potatoes. Sweet potatoes are a sustainable crop for Florida since they prefer tropical/subtropical climates, require minimal demands for irrigation and fertilization (half of the nitrogen that is required by the potato crop), and they offer a higher nutritional value than chipping potatoes. Additionally, literature suggests that sweet potato vines can be used as a supplement for cattle feed; therefore the entire crop -- both the roots and the aerial vines -- can potentially be marketed to increase profit margins. Complete utilization of any crop is environmentally sustainable since it promotes minimal waste and efficient land use.

    Despite the perceived advantages, there are several unknowns associated with the production and marketing aspects of sweet potato in Florida include: Ideal planting dates; success rate of newly developed cultivars; influence of target pests such as the sweet potato weevil, which is prevalent in Florida; establishing suitable conditions for the post-harvest curing process; branding a new cultivar line; and finding local grocery markets interested in the product.

    Our proposed solution is to conduct two trials on a newly developed, unique purple-flesh sweet potato during the 2019 and 2020 growing seasons. The cultivar is officially referred to as Charleston purple as the breeder is based in South Carolina. We are excited to conduct science-based research with this cultivar and explore Southern markets such as the First Coast Fresh produce line. Production trials on this cultivar are also on-going in California and South Carolina. Sweet potato offers a second cash crop for all TCAA potato growers during their off-season and the results of this project will be disseminated to all producers in the Tri-County Area.

    This is NOT genetically engineering plant material, rather is has been bred with conventional methods crossed with bees or by hand pollination from male to female parents. The characteristics of this sweet potato compared to a typical orange-flesh cultivar is that it has a higher dry matter content and less sweetness. Purple-flesh sweet potatoes contain anthocyanins, which are the reddish-purple pigments found in blueberries and blackberries and have been associated directly with higher levels of antioxidant activity. Complete nutritional analyses is necessary to better understand the perceived health benefits of the purple-flesh compared to a typical orange or yellow-flesh sweet potato.

    Project objectives from proposal:

    • To determine agronomic yields associated with early and normal planting dates for the purple-flesh sweet potato.
    • To determine if the purple-flesh cultivar has any nutritional advantages when compared to a conventional orange-flesh cultivar.
    • To determine if the vines can be harvested and ensiled efficiently for use as livestock feed.
    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.