Plant Pillow Preparation for the Veggie Plant Growth System on the International Space Station

The first Veggie plant growth chamber was installed on the International Space Station in 2014. Crop plants can be grown in Veggie using plant pillows, small rooting packets that contain substrate, fertilizer, and germination wicks along with attached seeds. The pillows were designed to interface with the Veggie root mat reservoir watering system to provide a capillary water column to growing plants. In preparation for flight, methods of arcillite substrate washing, autoclaving, and drying were established to reduce dust and to provide a dry sterile substrate. A controlled released fertilizer mixed into arcillite substrate provides nutrition for plant growth. Methods of seed surface sterilization were tested for both germination and microbial contamination, and the optimum methods were determined for candidate flight crops. Plant pillows were prepared for flight by cutting and inserting germination wicks, filling with the substrate/fertilizer mix, and sewing closed. Following pillow filling, seeds were attached to the wicks, and the pillows were packaged for flight. Pillow preparation methods have been successfully tested in the VEG-01 hardware validation tests on the International Space Station with ‘Outredgeous’ lettuce and ‘Profusion’ zinnia, and in the VEG-03 test, using ‘Outredgeous’ lettuce and ‘Tokyo bekana’ Chinese cabbage.