Preliminary species and media selection for the Veggie space hardware.

Abstract

Plants will be an important component of off-Earth life support systems for food production and atmosphere recycling. Veggie is a small vegetable production unit designed for space flight, with a passive water delivery system. Plants can be grown in Veggie using pillows, small bags with a wicking surface containing media and fertilizer. Pillows planted with seeds can be placed on the wicking surface of the Veggie reservoir and water will wick throughout the media. Multiple small salad and herb species were grown under Veggie analog conditions in pillows using both commercial peat-based media and arcillite. Biometric measurements and microbial loads were assessed. Growth varied, and some species grew better in a particular media but no general trends were apparent. Subsequent tests were conducted with lettuce using additional growing media. Lettuce plants grew best in the blends of the peat-based and arcillite media. Microbial counts were lower on plants grown in arcillite. Four media types (peat-based mix, arcillite, and blends of the two) were tested with in the rooting pillows; tests included Chinese cabbage, Swiss chard, lettuce, snow pea, and radish. Most species grew best in blends of the commercial mix and arcillite. Edible biomass production varied from 3.5-8 grams dry mass/m2/day with lettuce lowest and Chinese cabbage highest. Radish plants showed an increasing percentage of partitioning to edible roots with increasing arcillite in the media. Pillows appear to offer a simple, effective strategy for containing rooting media and avoiding free water while growing plants in the Veggie hardware.