Aeroponics Enables Consistent Cutting Propagation of Kratom (Mitragyna speciosa): Impacts of Photoperiod, Cultivar, and Rooting Hormone

Mengzi Zhang¹Cynthia Montanez²Brian J Pearson³Yuncong Li⁴Jianjun Chen^1*

• ¹Environmental Horticulture Department, University of Florida Mid-Florida Research and Education Center, Apopka, United States
• ²University of Florida Mid-Florida Research and Education Center, Apopka, United States
• ³Mid-Columbia Agricultural Research and Extension Center, Oregon State University, Corvallis, United States
• ⁴Department of Soil, Water, and Ecosystem Sciences, University of Florida Tropical Research and Education Center, Homestead, United States

Kratom (Mitragyna speciosa) has gained increasing attention for its potential to manage pain and alleviate opioid withdrawal symptoms. Despite growing interest, cultivation practices, including vegetative propagation, remain underexplored. This study compared indoor aeroponics with greenhouse mist systems for rooting kratom cuttings and evaluated the effects of photoperiod, rooting hormone, and cultivar on the rooting success. In Study I, a total of 180 ‘MR-Malaysian’ cuttings were placed in aeroponic units, 15 cuttings per unit. Twelve aeroponic units were randomly assigned to 10-, 14-, or 24-hour photoperiods in environmentally controlled growth rooms, with four units per room, and evaluated over two seasons. In parallel, 60 cuttings, 15 per tray, were placed under a greenhouse mist system for comparison across three seasons. A 14-hour photoperiod significantly enhanced root initiation and growth compared to a 10-hour photoperiod, as indicated by increased root length, area, crossing, and dry mass. The aeroponic system consistently promoted high rooting percentages (85%-92%) and root growth, whereas the greenhouse mist system exhibited high seasonal variability (7%-98%) and inconsistent rooting success. In Study II, cuttings derived from three kratom cultivars (MR-Malaysian, DR-Bumblebee, and Hawaii) were tested simultaneously using two propagation methods: indoor aeroponic and greenhouse mist systems, with or without rooting hormone treatments (5 mg/L IBA and 2.5 mg/L NAA). ‘MR-Malaysian’ overall outperformed the others, exhibiting high rooting rates and root growth with a relatively short production cycle, as well as being less susceptible to Fusarium. While hormone application increased root number in aeroponic system, it had minimal effects on other parameters. Our results showed that the aeroponic system consistently yielded a significantly higher rooting percentage and better rooting quality compared to the greenhouse mist system across all three cultivars. Such qualities included greater final root number, root dry mass, root length, root area, root volume, and higher numbers of root tips, forks, and crossings. However, the aeroponic system may pose a possibility of spreading pathogens. This study, for the first time, demonstrates that photoperiod, rooting system, and cultivar are crucial factors in rooting kratom cuttings. The aeroponic system represents a new and effective way of propagating kratom cuttings year-round.