Dry back is the intentional reduction of substrate VWC% (volumetric water content) between irrigation events. After reaching peak VWC at field capacity, the crop is allowed to transpire and deplete moisture to a target level before the next irrigation cycle.

Managing dry back gives you direct control over plant stress response, root development, and generative vs vegetative growth balance.

• Generative Higher dry back (30–50%+) — triggers stress response, promotes flowering, fruiting, and root zone development. Less water = reproductive signal.
• Vegetative Lower dry back (10–25%) — keeps substrate wetter, promotes shoot growth, canopy expansion, and vigorous vegetative development.
• Transition timing and magnitude determine how aggressively you steer the crop.

• Set Target Peak VWC% to the water content at the top of your irrigation cycle (field capacity for your substrate).
• Set Dry Back % to how much you want to reduce from peak.
• The Dry Back VWC% Goal is the substrate reading where you trigger the next irrigation.
• Monitor your substrate sensors and irrigate when VWC hits the goal.

• Athena crop steering protocols vary by cultivar, growth stage, and environment. Calibrate with your local data.
• Dry back targets interact with EC strategy — a heavier dry back often pairs with lower frequency, higher EC shots.
• Sensor placement matters: measure at mid-slab, not edges.