High-tunnel Organic Ginger: Response to Propagation Material, Fertilizer, and Prepropagation Rhizome Storage

Abstract

Ginger (Zingiber officinale, Roscoe) is a tropical rhizome crop typically grown from rhizome pieces, but can also be produced from seedlings. No information is available on how the seedling method compares with the rhizome piece method in organic ginger culture. In addition, information on the growing of organic ginger in the mid-Atlantic region is lacking. Some of the challenges include limited knowledge of rhizome storage, types of propagation materials for planting in the field or high tunnel, and acceptable organic fertilizers that will not increase the excess P currently polluting the Chesapeake Bay watershed. The objective of this study was to assess plant development, soil nutrients, and economic feasibility of organic ginger derived from different storage conditions and planting materials when grown in different nutrient sources in a high tunnel. Three types of plant material (single-shoot transplant seedlings derived from 36.5–40.0 g/rhizome, multishoot transplant seedlings derived from 60–120 g/rhizome, and rhizome seeds of 60–120 g) and three fertilizers types [cotton seed meal, 6N–0.9P–0.8K (0.18 kg⋅m–2), plus AZOMITE (1 kg⋅m–2); Nature Safe, 13N–0P–0K (0.07 kg⋅m–2); and Phytamin All Purpose Liquid fertilizer, 4N–1.3P–3.3K (0.26 L⋅m–2)] were used in 2018. In 2019 and 2020, three types of plant material and two fertilizer types at modified rates from the 2018 study, plus two storage containers (pans and flats), were tested. In general, the rhizome storage container did not affect plant height, leaf soil plant analysis development (SPAD) index, and rhizome yield, and its effect on tillers was none or mixed. Fertilizer type had mixed effects on plant height and tiller number, and no effect on the leaf SPAD index. Rhizome yields in 2019 and 2020 were unaffected by fertilizer, but Nature Safe produced a greater benefit-to-cost ratio (BCR) and profitability index (PI) than Phytamin. Soil P was generally less in Nature Safe–fertilized soil than in Phytamin-fertilized soil. Multishoot seedlings produced the greatest rhizome yield, BCR, PI, and tallest plants, and had some of the highest tiller numbers. These findings show that it would be more profitable to use multishoot seedlings as planting material in high tunnels compared with single-shoot seedlings and rhizome seeds. Furthermore, the lower P levels in the Nature Safe–fertilized soils compared with the Phytamin soils, and greater PI suggest that using Nature Safe will be a better choice than Phytamin for growing organic ginger.