Module M1 - Climate & VPD

Files: packages/grow_core.yaml (VPD calculation, Phase 2), packages/grow_climate.yaml (setpoints + regulation automation, Phase 3), packages/grow_actuators.yaml (device control proxies, used by this module and the “Devices” dashboard view)

What’s implemented

Phase 2: VPD calculation, live Temperature/Humidity/VPD display, and historical charts with a time-range selector - see docs/docs/dashboard-2-climate.md. Purely observational.

Phase 3: day/night setpoints and tolerance bands for RH, Temperature, and VPD (decision R17), a regulation mode switch, and the regulation automation itself (automation.grow_climate_regulation).

Setpoints and flags

All nine setpoint/tolerance input_number helpers, input_select.grow_climate_mode, and the status flags are exposed on Dashboard 2’s “Climate & VPD” view, under “Climate Setpoints (Phase 3 config)”:

input_boolean.grow_climate_is_daytime - which setpoint set is active. Kept in sync automatically with Module M3 (Light, Phase 6) by automation.grow_climate_daytime_follows_light: it mirrors binary_sensor.grow_light_top_active (packages/grow_light.yaml), so this flips to Day exactly when the Top Light group turns on and to Night exactly when it turns off. You can still set it by hand at any time - it gets overwritten on the next light state change while the toggle below is on.
input_boolean.grow_climate_daytime_follows_light - master toggle for the sync above. Defaults on. Turn it off to go back to setting grow_climate_is_daytime manually (e.g. Top Light isn’t mapped/enabled yet, or your day/night split shouldn’t follow the light schedule). Unlike the module master switches below, this only ever changes a flag - it never drives an actuator directly - so it’s safe to leave on even before you’ve turned on automatic climate control itself.
input_boolean.grow_climate_control_enabled - master safety switch. Defaults off. Nothing is driven automatically until you turn this on - do that only after disabling any old RH Control VPD-/VPD+ automations, so two controllers never fight over the same device.
input_select.grow_climate_mode - “RH/Temp Direct” or “VPD Driven”, see below.
input_boolean.grow_climate_control_paused - automation-managed, turns on whenever a required sensor/actuator is unavailable (see Safety below).
input_text.grow_climate_last_decision - automation-managed, a short human-readable line explaining what the last regulation cycle decided and why (e.g. RH/Temp Direct: RH 68.0% > target 55.0+5.0 -> dehumidifier ON, humidifier OFF.) - the quickest way to understand what the automation is doing without digging through logs.

Regulation modes

RH/Temp Direct - classic hysteresis control straight against the RH and Temperature setpoints, independently. RH above setpoint + tolerance turns the dehumidifier on (humidifier off); below setpoint - tolerance turns the humidifier on (dehumidifier off); inside the band, both off.

VPD Driven - humidity is controlled using VPD itself as the target, instead of RH directly. VPD above setpoint + tolerance (air too dry relative to target) turns the humidifier on; below setpoint - tolerance (too humid) turns the dehumidifier on; inside the band, both off. This is the better fit for a tent or room with only an exhaust fan and no real way to control temperature directly - VPD mode keeps the one variable that actually matters (VPD) on target using only humidity control, without needing a working Temperature setpoint at all.

Temperature/AC control runs independently of the mode above, in both cases - it’s a separate axis. Only active if an AC is mapped on Dashboard 1; cooling-only (turns the AC on above setpoint + tolerance, off at or below setpoint), since no heater mapping exists in this project.

Safety (decision R7)

Every regulation cycle checks that the sensors it needs (temperature, humidity, and VPD if in VPD Driven mode) and the actuators it would control (dehumidifier/humidifier/AC, whichever are mapped) are all available. If anything required is missing or unavailable, regulation pauses - sets grow_climate_control_paused on, sends one persistent_notification (not repeated every cycle), and does not touch any actuator that cycle. It resumes automatically, with a “resumed” notification, once everything required is available again.

Trigger cadence

The automation runs on every relevant sensor/setpoint/flag change (near- instant reaction to real conditions or you adjusting a setpoint), plus a /5 minute fallback re-check in case a trigger was missed.

Day/Night sync with the Light module (Phase 6)

A second, independent automation - automation.grow_climate_daytime_follows_light

keeps grow_climate_is_daytime matched to binary_sensor.grow_light_top_active (Module M3, packages/grow_light.yaml) whenever input_boolean.grow_climate_daytime_follows_light is on (the default): Top Light on -> Daytime Active on -> Day setpoints; Top Light off -> Daytime Active off -> Night setpoints. It reacts on every light state change and once at Home Assistant startup, and runs regardless of whether grow_climate_control_enabled itself is on, since it only ever flips a flag, never an actuator.

If binary_sensor.grow_light_top_active is unavailable (no Top Light slots mapped/enabled yet - see docs/docs/module-light.md), it leaves grow_climate_is_daytime untouched and sends one persistent_notification rather than guessing, clearing automatically once a definite on/off state is seen again. Turn grow_climate_daytime_follows_light off at any time to go back to setting grow_climate_is_daytime by hand - useful if you don’t have Top Light mapped yet, or if your actual day/night split shouldn’t follow the light schedule 1:1.

Bug fix (2026-08-27) - this affected you if this sync never seemed to work: binary_sensor.grow_light_top_active didn’t actually exist under that entity_id before this fix (see docs/docs/module-light.md’s “Bug fix” note - a template entity’s entity_id comes from its display name, which for this entity was “Light: Top Light Active”, not from its unique_id). In practice that meant this automation’s state trigger never fired on a real light change, and every time it did run (HA startup, or the follow-toggle turning on) it read the nonexistent entity as unavailable and just sent the “sensor unavailable” notification instead of syncing anything - so the day/night sync has likely never actually worked since it was built, silently. Once the Light module fix is deployed (and, if you’d already deployed the pre-fix version, the one-time entity rename in docs/docs/module-light.md’s rollout checklist step 0 is done), this starts working immediately - no changes needed here in grow_climate.yaml itself.

Device control proxies (`packages/grow_actuators.yaml`)

Since the real actuator behind each function can change any time you re-map it on Dashboard 1, both the regulation automation above and the Dashboard 2 “Devices” view (manual on/off buttons for every mapped device, see docs/docs/dashboard-2-climate.md) go through a set of stable template switches (switch.grow_actuator_<function>) instead of the raw mapped entity_id directly. See the comments in that file for the full rationale - same pattern as the Phase 2 pass-through sensors, applied to switches.

Known issue (fixed in code, needs a one-time manual cleanup on your instance)

Four of the thirteen switch.grow_actuator_* proxies (Under Canopy 1/2, Exhaust, Circulation) were originally given friendly names that didn’t slugify to the entity_id the dashboard expects (e.g. “Grow Actuator: Exhaust Fan” auto-generates switch.grow_actuator_exhaust_fan, not switch.grow_actuator_exhaust) - Home Assistant derives entity_id from the name at creation time, unique_id alone doesn’t control it. This showed up as those four Devices-view tiles displaying “Entity not found” instead of the intended name. The names in packages/grow_actuators.yaml are now fixed to match, but because those four entities already got created once under the wrong entity_id, redeploying the fixed YAML alone won’t rename them - Home Assistant recognizes them by unique_id on reload and keeps whatever entity_id they already have.

One-time fix after redeploying: go to Settings -> Devices & Services -> Entities, search for grow_actuator_under_canopy_light and grow_actuator_exhaust_fan / grow_actuator_circulation_fan, delete those 4 stale entities, then reload the Template integration (or restart). They get recreated fresh under the correct entity_id, matching what the dashboard already references.

Rollout checklist before enabling automatic control

Deploy packages/grow_climate.yaml and packages/grow_actuators.yaml, check config, restart.
Set your day/night RH/Temp/VPD setpoints and pick a regulation mode on Dashboard 2.
Disable any pre-existing RH Control VPD-/VPD+ automation so it doesn’t fight the new one.
If Module M3 (Light, packages/grow_light.yaml) is deployed and at least one Top Light slot is mapped/enabled, leave grow_climate_daytime_follows_light on and confirm input_boolean.grow_climate_is_daytime flips at the same moment the Top Lights do - otherwise turn it off and set Daytime Active yourself.
Watch input_text.grow_climate_last_decision and the “Devices” view for a while with grow_climate_control_enabled still off, to sanity-check what it would decide.
Turn grow_climate_control_enabled on, ideally while you can watch the tent for the first cycle or two.