Evaluating Sorrel (Hibiscus sabdariffa) Varieties for Production in Florida

Progress report for OS21-146

Project Type: On-Farm Research
Funds awarded in 2021: $19,708.00
Projected End Date: 03/31/2023
Grant Recipient: University of Florida
Region: Southern
State: Florida
Principal Investigator:
Dr. Norma Samuel
UF/IFAS Extension
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Project Information

Abstract:

The goal of this study is to evaluate four varieties of sorrel to determine agronomic practices for successful production in Florida and economic viability as an alternative crop. Specific objectives:

  • Objective 1: To evaluate the production of sorrel in Florida.
  • Objective 2: To determine cost of production and economic viability.
  • Objective 3: To develop and distribute educational materials on sorrel production practices as part of an Extension and outreach effort.
  • Objective 4: To increase seed availability of best performing varieties.

Sorrel/Roselle (Hibiscus sabdariffa) is a crop of economic importance in many tropical and sub-tropical regions of the world. It belongs to the Malvaceae family and is known to be a very versatile crop with many uses. Roselle has been gaining popularity with small farmers, but formal research has not yet been undertaken at UF towards optimizing production and marketing systems. The purpose of this SARE-funded research project is to evaluate four sorrel varieties for production in Florida.

Methods: Two women farmers with organic operations were selected to host this on-farm demonstration trial. Four varieties were evaluated; ‘Local’ which was previously grown by the farmers; and ‘Festival’, ‘Black’ and ‘Day Neutral’, imported varieties from the United States Virgin Islands.

Measurements were taken of plant height; and yield with the bolls and calyces intact and with the bolls and calyces separated. The height measurements data was analyzed using ANOVA, and yield data using SAS GLIMMIX's linear modeling tool. For height, the growth rate was similar for each of the varieties. The varietal response throughout the time intervals (week of year) was similar in terms of plant height. For the harvested calyces with the bolls intact, the sorrel varieties 'Local' and 'Day Neutral' had comparable mean yield responses. The calyces without bolls assessment revealed that 'Day Neutral' had a significantly higher mean yield (weight) than 'Local.' Festival’ produced no marketable calyces until November and ‘Black’ produced none.

Conclusion: ‘Local’ and ‘Day Neutral’ varieties show the greatest potential as an alternative crop in Central Florida

Project Objectives:

The goal of this study is to evaluate four varieties of sorrel to determine agronomic practices for successful production in Florida and economic viability as an alternative crop. Specific objectives:

  • Objective 1: To evaluate the production of sorrel in Florida.

  • Objective 2: To determine cost of production and economic viability.

  • Objective 3: To develop and distribute educational materials on sorrel production practices as part of an extension and outreach effort.
  • Objective 4: To increase seed availability of best performing varieties.

A completely randomized block design will be used for this project. Plants will be spaced 3 feet between plants within row (33 feet row length), 6 feet between rows (18 feet per block) to allow for cultivation and harvest of the fruiting branches (Matthew, et al, 2011). There will be four rows per block, one for each variety being evaluated with 12 plants per row for a total of 192 plants. A distance of eight feet will be between each block. There will be a 3 feet buffer around the plot. Total area is 3,978 square feet (38’ x 102’).

Seeds will be started in a greenhouse using protocols for growing vegetables. Seed germination time can be reduced from over a week to three days by scarifying the seed coat. This ensures uniform germination (Matthew & Zimmerman, 2010). From seed germination to a transplantable seedling takes four to five weeks. Seedlings will be manually transplanted. 

Objective 1: To evaluate the production of sorrel in Florida.

On-farm trials will be conducted on an organic farm and a conventional farm in Central Florida. Four varieties will be evaluated in 2021. In 2022, evaluation will be made in the same locations with modifications based on 2021 findings, including a four week difference in planting dates to determine its effect on other production factors. Data will be collected on the following for each variety:

  • Insect, disease, weed, and or nematode problems - plots will be scouted weekly.
  • Plant development – measurements will be taken on plant height and width, time to first bloom
  • Yield – length and width of calyces, weight with and without seed boll

Data will be analyzed using ANOVA.

Objective 2: To determine cost of production and economic viability.

  • Cost of materials needed for production
  • Labor costs – planting, crop maintenance, harvesting
  • Profit and loss calculations

Objective 3: To develop and distribute educational materials on sorrel production practices as part of an Extension and outreach effort.

A field day will be organized in Years 1 & 2. These will be timed to occur after the second harvest. The field days will introduce farmers and Extension personnel to the botany of the crop, demonstrate production practices utilized, and preliminary yield data. The findings will be published in a factsheet, infographics, article in industry magazines such as Berry/Vegetable Times. Findings will also be presented at the Extension Professionals Association of Florida (EPAF), the National Association of County Agriculture Agents (NACAA), and Florida Horticultural Society annual meetings.

Objective 4: To increase seed availability of best performing varieties.

In order to develop a source of available seeds for farmers within the state, seeds will be saved from each of the varieties. Sample packets from those determined to be the best performers will be made available to farmers attending field days in 2022 who are interested in planting sorrel.

Cooperators

Click linked name(s) to expand/collapse or show everyone's info
  • Aubrey Cash - Producer
  • Stafford Crossman (Researcher)
  • Jessica Gentry - Producer
  • Dr. Juanita Popenoe (Researcher)
  • Matt Smith (Researcher)
  • Dr. Thomas Zimmerman (Researcher)

Research

Materials and methods:

A completely randomized block design was used for this project. Plants were spaced 3 feet between plants within row (18 feet row length), 6 feet between rows (18 feet per block) to allow for cultivation and harvest of the fruiting branches (Matthew, et al, 2011). There were four rows per block, one for each variety being evaluated with 7 plants per row for a total of 112 plants. A distance of 6 feet between each block and a 3 feet buffer around the plot. Total area is 2,304 square feet (24’ x 96’). This spacing was based on the typical growth height and width of the plants in the USVI. In Year 2, the within row spacing will be increased to 4 feet. We will keep the between row spacing the same due to space limitations.

Seeds were started in a greenhouse by Bountiful Farms using protocols for growing vegetables. Timing from sowing of the seeds to transplantable seedlings was four weeks. Seedlings were manually transplanted three days between each farm.

Objective 1: To evaluate the production of sorrel in Florida.

On-farm trials were conducted in Year 1 on two organic farms in Central Florida starting mid-June. Both farms amended their soil with compost to 1 inch depth  prior to planting. Four varieties: Local – the variety previously grown by farmers in the area; and three varieties from University of the Virgin Islands – Festival, Black, and Day Neutral (unaffected by day lengths) were evaluated in 2021. Data was collected from Plants #2; #4; and #6 on the following for each variety in each block:

  • Plant development – plant height measurements were taken at one month after planting and then every two weeks; and time to first bloom.
  • Yield – weight of calyces with and without seed boll. A specially designed tool was used to separate the calyces from the boll, so this allowed for consistency in amount of the calyces being removed/remaining on each boll.
  • Insect, disease, weed, and or nematode problems - plots will be scouted weekly.

Soil Testing and other Items

Since sorrel is not on the list of commodities for soil testing, okra was selected on the soil test form as the crop for nutrient recommendations, as sorrel is a relative.

Bountiful Farms – The soil pH prior to planting was 7.4 with high levels of P and low levels of K and Mg. Plants were planted in prepared ground with soil leveled.

Dirty Dog Organics – The soil pH prior to planting was 7.5 and nutrient levels for P, K and Mg were similar to what was observed at Bountiful Farms. Plants were grown on raised beds approximately 12 inches high and covered with fabric mulch which were buried in the rows with soil. Wood chips were added in the furrows in early September to keep weed growth to a minimum.

The crop concluded at the end of November when the plants began to senesce. Plant height measurements were analyzed using ANOVA and yield data using SAS GLIMMIX's linear modeling tool.

Objective 2: To determine cost of production and economic viability.

  • Cost of materials needed for production
  • Labor costs – planting, crop maintenance, harvesting
  • Profit and loss calculations

Farmers were asked to keep a detailed log of activities related to the crop and to share at the end of the project in 2023 to determine labor costs and profit and loss calculations.

Research results and discussion:

Cooperators

Year 1:
University of Florida Institute of Food and Agriculture Sciences (UF/IFAS) Extension

Bountiful Farms

Dirty Dog Organics

University of the Virgin Islands Agricultural Experiment Station (UVI AES)

Year 2:
Dirty Dog Organics replaced with Whispering Oaks Winery. Other partners remain the same.

Note: After the project was installed the research team realized that the scope of the project was too ambitious based on the time commitment needed to collect the amount of data outlined in the approved submission. Such a time commitment would warrant employment of a graduate student devoted to the project throughout the growing season, which would not be possible with the allocated budget. Thus, we modified the scope in a manner that would not affect the approved objectives of the project. A budget modification is not needed since the cost of materials being sourced for the project are sometimes higher than that which was approved. The materials and methods outlined are based on the new scope.

During the period the crop was in the ground, June to November, grasshoppers were the only insect pests observed in the field. However, they were not of sufficient levels to cause concern. We had significant rains in Central Florida during that time. Based on rainfall data collected from the two closest weather stations through the Florida Automated Weather Network (FAWN) Okahumpka received 24.72 inches and Ocklawaha received 36.88 inches of rainfall. This severely affected the crop at Bountiful Farms with the field reportedly remaining under water for 1-2 days at a time.

Bountiful Farms: In mid-July we noticed symptoms of green wilt in the ‘Black’ variety followed by some chlorosis, leaf drop and eventual death of the plant, if not removed when symptoms become visible. A sample was submitted to the UF/IFAS Plant Clinic in Apopka for diagnosis. The results determined that the cause of the wilt was Phytophthora. As the number of plants with these symptoms and white cottony mycelium at the base continued to progress throughout the field, we submitted another sample to the UF/IFAS Disease Diagnostic Lab in Gainesville. The results showed they were affected by a combination of Southern Blight (Sclerotium rolfsii) and Fusarium Crown and Stem Rot (Fusarium sp./spp.). By the end of August, of the plants from which we were collecting data, we had 0.08% of the ‘Black’; 50% of the ‘Local’ and ‘Day Neutral’; and 42% of the ‘Festival’ varieties remaining. By end of September only 20 plants remained in the entire field, so we decided to officially close out the season at Bountiful Farms on October 7th as there were too many missing data points on the plant height measurements.

Although we lost the crop at Bountiful Farms, we were able to conclude that sorrel is a crop that cannot tolerate wet conditions. These conditions resulted in plants that looked unhealthy and a combination of disease problems that could possibly render the crop a loss especially in an organic enterprise where products for disease control may be limited. Farmers in Florida interested in planting sorrel should locate their field in the higher area of their property that has good drainage.

Dirty Dog Organics (DDO): At DDO we lost 2 ‘Black’ and 1 ‘Festival’ plants from the selected plants for data collection. Squirrels were the main pest of concern on this farm once the calyces were developed. They would collect the bolls and chew them in the large oak tree near the field so you could see the remnants below the canopy each day.

The growth rate measured in inches from base of plant to growing point was explained   by the week of the year (WoY) rather than the month. Plant height measurements were     taken starting at Week 29 (4 weeks after transplanting) and continued every two weeks until week 35.  At that point  plants were becoming top heavy with foliage and tilting. The data was analyzed using ANOVA. The varietal response throughout the time intervals (week of year) was similar in terms of plant height. The increase in growth parameters between weeks 29 and 33 is consistent with expected growth outcomes.

SAS GLIMMIX's linear modeling tool was used to evaluate the data collected from DDO.  For the harvested calyces with the bolls intact, the sorrel varieties 'Local' and 'Day Neutral' had comparable mean yield responses. The calyces without bolls assessment revealed that 'Day Neutral' had a significantly higher mean yield (weight) than 'Local.' The yield was explained by the week of the year (WoY) rather than the month and the mean yield responses for with- and without-boll calyces followed a similar pattern. The largest yields were achieved in weeks 40 and 41, with yields gradually declining in week 42. The significantly higher mean yield (weight) of the ‘Day Neutral’ without bolls makes this an ideal variety to sell in this form to as it would take fewer calyces to make a pound compared to the ‘Local’. ‘Festival’ produced no marketable calyces until November and ‘Black’ produced none.

The ‘Local’ and ‘Day Neutral’ varieties are suitable for production in Central Florida with multiple harvests received before the crop senesces. Since the ‘Day Neutral’ variety is technically supposed to be able to give a crop year-round, Central Florida farmers could start the seedlings early in the greenhouse and plant after the danger of frost has passed in mid to late March, then plant a second crop of ‘Day Neutral’ and/or ‘Local’ in June or July to extend the cropping season. Because the sorrel leaves are edible, Dirty Dog Organics capitalized on the opportunity to harvest leaves from the crops to sell as greens to provide an added source of income. Because the plant grows so rapidly, you could hardly detect that the leaves were being harvested.

The sorrel plants get top heavy as they start to produce and fall over which makes it difficult to maneuver between the rows during harvest. Thus, we recommend that the spacing between rows be increased. The crop could also be planted in a single row as a perimeter crop.

Twenty-one people attended the field day and 13 identified as farmers, our primary target audience. A QR Code was provided on site for the attendees to complete an end of event survey. Some completed it on site. An email reminder was sent to complete the survey which resulted in a combined total of 15 respondents, all of whom showed an interest in growing sorrel in the future. This suggests that the farmers are considering growing sorrel as an alternative crop. Ninety-three percent of those surveyed also indicated they planned to share what they learned about sorrel with those in their network.  

Participation Summary
2 Farmers participating in research

Educational & Outreach Activities

2 On-farm demonstrations
2 Published press articles, newsletters
1 Webinars / talks / presentations
2 Workshop field days

Participation Summary:

2 Farmers participated
Education/outreach description:

Multiple approaches will be used to educate farmers, extension faculty, and other stakeholders on the outcomes of this project. These include:

  • Field days – one per year in fall of Years 1 & 2 before the second harvest. Production practices and data collected to that point will be shared with farmers. Promotional flyer will be developed to promote this event using fruit and vegetable email lists, social media, mass media, extension calendars, farmer organizations, etc. Each field day will be opened to 50 farmers on a first come first served basis. The group will be divided into two and rotate between an oral presentation and field tour of the plots. Should we make this a rotation between the conventional and organic farm instead then meet up at the end for refreshments? Or should we have two field days each year? The groups will then combine for light refreshments featuring products made from sorrel. For example, sorrel drink, sorrel nectar, sorrel jam, sorrel chutney, sorrel pie/ice cream. The local media and IFAS Communications will be invited to cover the event. Under present University Covid-19 policy, we will be able to hold this event, but will need to ensure participants can socially distance, wear face masks, and provide hand sanitizers and or stations for handwashing. The serving of food is discouraged under current policy, so serving refreshments at the event may need to be canceled or altered to a take-away format if an exception cannot be granted.
  • Virtual Webinar through Zoom or Teams – Spring 2022 to share production data. Farmers, extension professionals, industry representatives will be invited to participate using the promotional avenues previously listed.
  • Facebook Live – Agents will share progress of the crop through short Facebook Live broadcasts on their respective county’s Facebook page during the growing season.
  • Publications – An extension factsheet on sorrel production will be submitted for publication on https://edis.ifas.ufl.edu/ in early February or March of 2023. Write article for the Berry/Vegetable Times magazine. Journal articles will be submitted to the Journal of Extension and or the Journal of the National Association of the County Agricultural Agents (NACAA). An infographic providing a quick snapshot of the crop will also be developed in collaboration with IFAS Communications.
  • Presentation at Conferences – Applicants will submit abstracts for presentation of findings at the following conferences in 2022 and 2023: NACAA, Extension Professionals Associations of Florida (EPAF), Florida Horticultural Society

Farmer Field Day – The research team worked with two interns from the Active Learning Program at UF to develop a flyer to promote the event and a survey to obtain feedback from the attendees on the day of the event. Each of the team members distributed the flyer to their respective mailing lists, and personally targeted invites to the Florida Black Farmers and Agriculturalists Association and the Florida Fruit and Vegetable Growers Association. The event was held on November 9th at Dirty Dog Organics. Twenty-one persons were in attendance and included farmers, entomologists, food scientists, visitors from College of Agriculture, Science and Education (CASE) in Jamaica, one of whom also has a farm in LaBelle Florida. UF/IFAS Communications supported the event through media releases, blog posts, and real time posts on social media during the event.  https://blogs.ifas.ufl.edu/news/2021/11/10/sorrel-as-a-new-crop-for-florida/.

The attached agenda will provide insight on topics covered at the field day. Dr. Zimmerman commented that he has organized and attended many field days and he was very impressed with the methodologies the team used to engage the participants and plans to model future field days he conducts the same way.

  • Sumter County Farm City Week – This is an annual event for residents showcasing agriculture in Sumter County. The 2021 outdoor event was held on November 12. Norma Samuel made a presentation with props to 53 attendees on Florida Cranberry (Sorrel/Roselle): An interesting and easy to grow edible for Florida gardeners.
  • Social Media Posts – Throughout the season posts were made on Facebook on the UF/IFAS Extension Sumter County; Sustainable Agriculture & Food Systems – Sumter, Pasco, Hernando County; and UF IFAS Extension Sumter County Urban Horticulture & FFL Program Facebook pages.
  • New Master Gardener Class Training – Extra seedlings of each variety were planted in the demonstration gardens at the UF/IFAS Extension Office in a high visibility area. Dr. Samuel integrated sorrel production into her presentation on vegetable gardening by taking the 8 class participants to the garden to introduce them to the crop.

Project Outcomes

Project outcomes:

The project outcomes are outlined according to objectives:

  • Objective 1: To evaluate the production of sorrel in Florida.
    • The ‘Day Neutral’ and ‘Local’ varieties are more suited for production in Central and possibly North Florida, since they come into production a lot sooner than the ‘Black’ and ‘Festival’ varieties and allowed for multiple harvests before frost. We hypothesize that the ‘Black’ and ‘Festival’ varieties would be more suited for South Florida, since they bloom later in the season; this would allow for an extended production/harvesting season.
  • Objective 2: To determine cost of production and economic viability.
    • The cost of production and economic viability of growing sorrel commercially in Florida will be assessed at the end of the second growing period based on combined data from both seasons.
  • Objective 3: To develop and distribute educational materials on sorrel production practices as part of an Extension and outreach effort.
    • Year 1: Activities focused on bringing awareness to the crop by promotion of sorrel through our networks. The following abstracts were submitted for presentation at professional conferences:
      • National Association of County Agriculture Agents – West Palm Beach, Florida. July 17 – 22, 2022. On-Farm Evaluation of Sorrel (Hibiscus sabdariffa) Varieties for Central Florida Commercial Production. Status - Accepted.
  • Extension Professionals Association of Florida (EPAF). Panama City, Florida. August 29 – September 1, 2022. Sorrel Field Day: A Tasteful, Interactive Farm Visit Showcasing a Versatile Alternative Crop. Status - Awaiting notification.
    Year 2 Plans:

    • The combined findings will be published in factsheet(s), infographics, and article(s) in industry magazines such as Berry/Vegetable Times.
    • Virtual webinar on Growing Sorrel in Florida.
    • Farmer Field Day(s) – The male farmer who will be participating in the project in Year 2 has expressed an interest in hosting a field day at his farm. Thus, we will potentially have two field days in 2022 as Bountiful Farms is scheduled to host this year.

  • Objective 4: To increase seed availability of best performing varieties.
    • Each attendee at the Sorrel Farmer Field Day received a packet of about 20 seeds of either the ‘Local’ or ‘Day Neutral’ Varieties as these were the early performers in the area.
    • We hypothesize that the ‘Festival’ and ‘Black’ varieties will perform better in South Florida. Thus, seed packets of the ‘Festival’, ‘Black’, and ‘Day Neutral’ varieties were shared with the horticulture agent at UF/IFAS Extension Office in St. Lucie County to evaluate in their demonstration gardens for the 2022 growing season.
    • In 2022 – 2023 we will distribute seeds to farmers who indicate an interest in growing sorrel. Varieties provided will depend on location in the state.

Participants

No participants
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.