Better understanding of food production using in situ resources such as lunar regolith is necessary as we advance to establish an ongoing presence on the moon. The potential of lunar regolith to serve as a viable substrate for plant growth has yet to be studied. We investigated the feasibility of using lunar regolith for cultivation of two lettuce cultivars (‘Outredgeous’ and ‘Rex’) in two types of simulants, JSC-1A (lunar mare) and OPRH4W30 (lunar highlands), compared to inert substrates peat and rockwool, with and without a complete nutrient solution. The experiment was conducted under controlled conditions (200 µmol m-2 s-1, 25/22 °C, and 70% relative humidity) in a walk in growth chamber, assessing seed germination, seedling growth, and biomass accumulation over three consecutive plantings. In the first harvest, peat and rockwool with nutrient supplementation yielded the greatest fresh and dry mass, while regolith with deionized water severely stunted growth. Nutrient supplementation enhanced plant growth in regolith, with an 8.4-fold increase in shoot fresh weight and a 7.3-fold increase in leaf area for ‘Rex’ grown in JSC-1A compared to those grown with deionized water. Similar responses were observed in ‘Outredgeous’ and in the OPRH4W30 simulant. However, plant growth in simulants was substantially reduced, up to 13.5 times smaller, compared to rockwool and peat, even when supplemented with the same nutrient solution. However, growth in both regolith types with nutrient supplementation improved with subsequent plantings. Seed germination varied across substrates in initial planting, averaging 67% in OPRH4W30, 77% in the JSC-1A, and 88-93% in peat and rockwool, but increased to over 85% in both regoliths in the second and third plantings. These results highlight regolith’s potential to support crop growth with proper nutrient management strategies and recycling for lunar agriculture, underscoring the possibility for using in situ lunar resources for food production for long-term lunar habitation.
