The growth of Swiss chard in compost, Mars regolith simulant, and mixtures thereof, was studied for application in Advanced Life Support (ALS) systems, particularly Mars/lunar based operations. The purpose was to begin characterizing a sustainable biomass production method based on compost derived from inedible biomass. Compost would serve both as a means of recycling plant nutrients while improving the physical qualities of regolith as a plant growth medium. An outpost’s cropping area could be expanded by blending a minimal amount of compost (scarce, initially imported resource) and a maximal amount of regolith (plentiful local resource), consistent with adequate crop yields. Swiss chard was selected for the study as it is an ALS crop candidate for which there are little data.