2019 ASHS Annual Conference

In establishing colonies on Mars, food crops will need to be grown. Assuming that Earth soil or growing media will not be taken to Mars because of the expense, crops would most likely be grown in soil on Mars or grown hydroponically. As an alternative to adding organic matter to the soil, could the Martian soil be used in combination with the nutrient solution in a hydroponic system? The objective of this study was to determine the effects of simulated Martian soil in a noncirculating hydroponic system on the growth of 'Koba' green onion plants. 'Koba' green onions (Allium fistulosum L.) seeds were started in Oasis® cubes under T5 high output fluorescent lighting in a lab. Seedlings were then transferred to seedling starter trays. In the simulated Martian soil treatment, 20.5 g of soil was added around each Oasis cube in the cell with the soil reaching the top level of the Oasis cube. The simulated Martian soil was The Martian Garden’s unsorted grade MMS-1 Mars Regolith Simulant. The other treatment was the hydroponic solution. The seedling starter trays were placed in small trays, and 500 ml of a hydroponic nutrient solution was added to each tray. The nutrient solution was Hydro-Gardens' Chem-Gro lettuce formula 8-15-36 hydroponic fertilizer with added calcium nitrate (19% Ca and 15.5% N) and magnesium sulfate (9.8% Mg and 12.9% SO₄). The seedlings were grown under red LED lighting (119 μmol/m²/s, 12-h photoperiod). One hundred ml of the nutrient was added daily to the trays. At the end of the study, there were no significant differences between the simulated Martian soil treatment and the nutrient solution treatment for plant height, total leaf length, average leaf length, number of leaves, leaf dry weight, and stem diameter. In conclusion, the simulated Martian soil could be used in conjunction with the nutrient solution in a noncirculating hydroponic system.