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Do Plants Need Water at Night?
The question whether plants need water at night is a common one, and it is particularly relevant to the Integrated Aqua-Vegetable System (iAVs), which uses a timed irrigation system.
Night Time Irrigation
In iAVs, the pump is controlled by a timer, and irrigation events occur for 15 minutes every 2 hours, starting just before dawn. There are no irrigation schedules at night, which raises the question of whether plants need water at night.
Plant Needs and Transpiration
Plants do not transpire at night, which means that they are not “taking up” water at night. This is because plants have entirely different metabolic processes occurring in the dark. The roots and rhizosphere processes benefit from abundant oxygen, and all the aerobic soil organisms do also.
The “idea” around not flooding at night is to allow time for microbes to proliferate (multiply) and actively metabolize substrate without interruption. This helps plant dark-respiration/metabolism and conserves energy required for lifting water.
Energy Savings
Not pumping water at night saves energy and reduces the workload on the system. This is particularly important in areas where energy is scarce or expensive.