View on GitHub

Smart Irrigation

A maintained community fork of the Smart Irrigation Home Assistant integration — precise, evapotranspiration-based irrigation scheduling

Experimental features

Main page: Configuration
Previous: Sensor group configuration
Next: Distributors

The Setup → Experimental tab holds opt-in features that are off by default and still being refined — turn them on one at a time and keep an eye on things; you can switch them back off at any time without losing data. Two change how each zone's bucket is filled; a third gates the experimental mechanical water distributor support.

The two bucket toggles are global (they apply to every zone) and take effect from the next calculation or watering event onward.

Looking for forecast-weighted durations? That option moved out of this tab. It is now the Water less choice in the unified When rain is forecast control under Setup → When to Water. The behaviour is unchanged.

Credit bucket from observed watering

Smart Irrigation keeps its soil-moisture model honest by accounting for the water it applies. But if you water a zone by other means — a manual tap, a Home Assistant automation, your own schedule driving the valve — the integration normally doesn't know, and the bucket drifts from reality until the next weather calculation.

When enabled, Smart Irrigation watches each zone's linked valve/switch entity. Whenever that valve runs outside Smart Irrigation, the bucket is credited for the water applied. The amount is estimated from how long the valve ran and the zone's configured throughput (run time × throughput ÷ size), so the zone needs both a linked valve and a throughput set.

Notes:

Live-estimate watering

By default a zone waters once a day: the daily calculation runs — for example at 23:00 — produces a deficit, and the next scheduled run waters it off. That's correct for the daily ledger (the daily ET science needs a full day of weather), but it means a second scheduled run a few hours later finds the bucket already satisfied and does nothing. There is deliberately no "calculate every N hours" — daily ET0 can't be chopped into sub-daily pieces.

When enabled, each scheduled run instead decides and sizes itself from the live intra-day deficit shown by each zone's Live bucket sensor (the drainage-aware ET and rainfall accumulated since the last calculation — computed with a valid hourly method). This means:

The trigger honours each zone's bucket threshold (minimum deficit), so it won't churn out tiny runs — it only fires once the live deficit crosses that threshold.

The daily bucket ledger is left exactly as-is — only this run's start and duration come from the live estimate. The subtlety is avoiding a double-count: the live deficit can be deeper than the stored bucket because the intra-day ET hasn't been folded into the ledger yet. So after a live-estimate run, instead of forcing the bucket back to zero, Smart Irrigation credits the water it actually delivered (run time × throughput ÷ size, capped at maximum bucket). The leftover deficit therefore persists honestly, and when the next daily calculation subtracts the day's full ET it does so from a water-credited bucket — never subtracting the intra-day ET twice.

Example (two runs in a day). Monday's calculation leaves a zone at −5 mm. By the 07:00 run another 1 mm of ET has accrued (live deficit −6 mm) → it delivers 6 mm and the bucket is credited to +1 mm. By the 19:00 run the cumulative daytime ET is 5 mm, so the live deficit is now −4 mm → it delivers 4 mm and the bucket goes to +5 mm. At 23:00 the daily calculation subtracts the day's full ET; because the bucket only ever banked the water delivered (never had intra-day ET subtracted), the result lands on the true carryover — no double-count.

Notes:

Mechanical water distributors

Enables Smart Irrigation's support for a mechanical pressure-distributor (for example a Gardena Water Distributor) that splits one supply into several outlets. Turning it on reveals the Distributors setup tab and a per-zone Water distributor field; leaving it off keeps the feature entirely hidden. Unlike the bucket features above this does not change any calculation — it is a new, experimental capability that could not be fully hardware-tested, so treat it as a beta and watch the first days of use closely. Full details are on the Distributors page.

Main page: Configuration
Previous: Sensor group configuration
Next: Distributors