Table 4

Optimal environmental conditions for crop growth in Growing Underground

Environmental factorFor lettuce, from literatureAdapted values for Growing Underground
TemperatureBetween 20 and 25°C, optimal water and air at 24 °C (Thompson and Langhans, 1998)Night time: 17-22°C
Daytime: 21-26°C
Relative HumidityBetween 60 and 80%Between 45 and 65%
CO2 concentrationKeep above 400ppm, optimal at 1000ppm, carbon enrichment only with less than 3.5 ACHKeep air change per hour as low as possible (measure is ventilation setting)
Air current speedSignificant yield improvements from 0.01 to 0.2 m/s,By location: 1 m/s through the corridor yields 0.1-0.3 m/s over the crops on most shelves
No significant change past 0.5 m/s
LightHigh LUE at early growth stagesData not available yet, currently 18 hours.
Photoperiod of 18 hours optimal (Tei, Scaife and Aikman, 1996)

or Create an Account

Close Modal
Close Modal