The lettuce and radish crops were grown in environmental growth chambers located in the Space Life Sciences Laboratory (SLSL) of NASA Kennedy Space Center. The lettuce and radish seeds were be planted in 10 plastic pots (7 em tall, 164 mL capacity, four seeds per pot) containing Canadian sphagnum peatmoss. A 1 inch (2.5 em) layer of sifted arcillite (particle size > 2 mm) was placed at the bottom of each pot to generate a perched water table accessible to plant roots. Within the growth chamber, the pots were arranged inside a 0.3 m 2 tray under each light treatment. To minimize edge and position effects within the chamber, the pots were rearranged and rotated every other day. The water use was tracked daily by recording water levels in the trays, and recording the amount of water added. The air temperature, relative humidity, and C02 levels were maintained at 23° C, 70%, and 1200 !lJllol•mor1 , respectively.