P1, P2, and P3 Cannabis Irrigation Explained

P1 is the first irrigation phase after lights-on. Its stacked events move the root zone from overnight dryback toward the operating moisture range without relying on one oversized application.

The first event should not be chosen from the clock alone. Crop stage, substrate volume, overnight dryback, root activity, and the room's established operating plan all matter. Core Cannabis keeps the configured lights-on delay and each P1 event visible so the grower can review the assumption instead of inheriting an unexplained controller program.

P1 volume is the sum of its events. Three 240 mL shots equal 720 mL per plant before P2 begins. Looking only at one shot can hide the actual recharge delivered during the morning stack.

P2 events are the maintenance phase. Their count, size, and placement should come from the approved crop-day baseline and any valid same-day response for that exact table.

P2 should not be treated as a duplicate of P1. Its job is to respond to daytime water use while protecting the planned finish time. A table that is holding moisture may need no biological correction, while a table drying faster can justify a station-specific change when the accepted response rules support it.

Controller timing coordination can keep valves inside a workable hydraulic window, but that does not make plant response room-wide. A reading from one table belongs to that table.

P3 begins after the final P2 event completes. It is not a missing shot. It is the deliberate dryback period that continues through lights-off and into the next irrigation cycle.

The end of the final runtime matters more than the displayed start time. If a station begins at 10:00 and runs for six minutes, P3 starts after 10:06 for that station. That distinction keeps dryback calculations tied to actual delivery rather than a rounded schedule label.

A recovery event after the cutoff changes the dryback window. It should therefore be an explicit, operator-reviewed exception with its own reason and log evidence, not a hidden repeat added by the controller.

Shot percentage expresses the event relative to the configured substrate water-volume basis. Milliliters express the physical target delivered to one plant. Runtime then translates those milliliters through measured emitter flow.

For example, a 3.2% event against a 7,500 mL configured substrate basis is 240 mL. If measured delivery is 38 mL per minute, the controller runtime is about 379 seconds. Changing emitter flow should change runtime, not silently change the 240 mL biological target.

A schedule card proves what was intended. A controller program proves what was stored. A controller log proves what ran. Reliable irrigation operations keep those three records distinct and compare them when a room reports a missed, short, or overlong event.

The practical daily question is simple: did every mapped station start near the expected time and run for the expected duration? If not, recovery should be based on the missing volume and the remaining safe window, never on the connection badge alone.