Impact of Production System and Cultivar on Yields of Roselle (Hybiscus sabdariffa) Leaves and Calyces

Impact of Production System and Cultivar on Yields of Roselle (Hybiscus sabdariffa) Leaves and Calyces

Summary

Reliable sources of seed continue to be a limiting factor in producing commercial quantities of Roselle (Hibiscus sabdariffa). Plants from the 2011 season moved into a greenhouse for seed production over the winter were less productive than anticipated. For the 2012 summer season, cooperating farmer Morris Gbolo obtained an adequate supply of seeds of the variety Thai Red/Red Roselle from Baker Creek Seed, Mansfield, MO, to be able to grow two 200 feet long rows of Roselle for his pick-your-own operation at B and B Farm in Galloway Township, NJ.

Neither additional quantities nor other cultivars of Roselle were readily available for trialing so field work was limited to a yield trial comparing bare ground vs. black plastic mulch production systems at the Gbolo farm. Subplots established within the rows of plants growing either on bare ground or on black plastic mulch allowed season-long measurements of yield of shoots and leaves over multiple harvests. Plots provided an added bonus this season when the crop blossomed and produced the prized calyces that are used by many ethnic cultures.

• Morris Gbolo planting Roselle seedlings in black plastic mulched beds.

Objectives/Performance Targets

A demonstration trial consisting of side-by-side 200 feet long flat beds with or without black plastic mulch and drip irrigation was established on the Atlantic County, NJ farm operated by Mr. Morris Gbolo. Roselle var. Red Roselle/Thai Red seeds planted on 3/31/2012 in 48-count cell trays filled with commercial peat-lite mix. Seedlings were grown in a greenhouse for 8 weeks. Seedlings were transplanted by hand into the field beds on 6/12. Rows were spaced 4 feet on center and plants were placed 18 inches apart within the each row. Five sub-plots consisting of 3 plants each were randomly placed in each row to compare season-long multiple-harvesting of young leaves and shoots. The plots were irrigated as needed via drip irrigation under the plastic mulch while overhead irrigation was applied to the bare ground plots.

Outreach efforts include a draft fact sheet on Roselle production to be published on the worldcrops.org website.

Accomplishments/Milestones

Over 4 harvests from early August through mid-September, there were no significant differences in yields of leaves and shoots between the bare ground and plastic mulched plots. Slightly faster growth on plastic mulched plots supported by higher first harvest yields, as well as earlier and greater abundance of flowers on the plastic mulched plots, was made in casual observations of the entire planting. However, variation across the plots did not support the apparent greater production, and over the full season, the plot-level differences between production systems was negligible. Full statistical analysis will be conducted to confirm observations.

The 2012 season produced a bonus when in early September, the Roselle plants in all plots began to blossom and produce the fleshy calyxes that are prized by some ethnic groups, especially Mr. Gbolo community from Liberia. Calyx production had not been observed in previous plantings in New Jersey and was thought to be limited by a short season. Not having used any early season extension techniques (high/low tunnels, hot caps, etc.) other than the early transplant production, blossoming was not anticipated.

• Table 1. Initial mean plant height (in.) at first harvest, plus mean and running total yields (pounds per acre equivalent) over multiple harvests of Roselle (Hibiscus sabdariffa) grown on bare or black plastic mulched flat beds in 2012.

Impacts and Contributions/Outcomes

The impacts of this project following this second season are the following observations:

• seed quantity and variety continue to be limiting factors to increasing production of Roselle;
  Roselle var. Thai Red grows well on both bare ground and on black plastic mulched beds producing an equivalent of 6882 and 7653 pounds of leaves and shoots per acre, respectively, over multiple harvests throughout the season;

• Producing the prized fleshy calyx of the Roselle blossom may be possible in southern NJ without season extending techniques. It may be possible to increase calyx production with earlier planting under protected culture, or to produce them at cooler sites further north.

• Flower buds with prized calyxes were a welcomed surprise in early September.
• In order to eat the fleshy calyx, Morris Gbolo demonstrates how to remove the internal flower bud.
• The fleshy calyx, a delicacy in Liberia and other West African cultures, is eaten in soups and stews.
• After slicing around the base, the flower bud can be removed.
• Roselle plantings established on bare ground (left) and black plastic mulched beds at B&B Farms in Galloway, NJ.
• Roselle plots at harvest time.
• Morris (left) and James Gbolo are excited to see calyxes forming in their Roselle planting.
• Once flowering begins, Roselle can be quite prolific.

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