diff --git a/install-stack.sh b/install-stack.sh
index 2409ca5..cb9ead9 100755
--- a/install-stack.sh
+++ b/install-stack.sh
@@ -2000,6 +2000,92 @@ ${build_out}"
   npm_add_location "/calendar/" "10.10.10.126" 3080
 }
 
+# Plant-room equipment monitoring — read-only MQTT telemetry (boilers, water
+# softener, calorifiers, pumps). No admin-VLAN NIC needed (unlike hvac): plant
+# only subscribes to the shared MQTT broker over the internal network, it never
+# talks to devices directly. Depends on deploy_mqtt_broker having already run
+# (see the ordering note above deploy_mqtt_broker in the main flow below).
+deploy_plant() {
+  msg_step "Plant Room (LXC 123 · 10.10.10.123)"
+
+  if [[ -z "${PLANT_DB_PASS:-}" ]]; then
+    PLANT_DB_PASS=$(openssl rand -base64 24 | tr -dc 'a-zA-Z0-9' | head -c 24)
+    printf '\nPLANT_DB_PASS=%s\n' "$PLANT_DB_PASS" >> "$CREDS_FILE"
+    msg_ok "Generated PLANT_DB_PASS → ${CREDS_FILE}"
+  fi
+
+  msg_info "Creating LXC 123"
+  create_lxc 123 "10.10.10.123" "plant" 1024 1
+  msg_ok "LXC 123 created"
+
+  msg_info "Installing Docker"
+  install_docker 123
+  install_mgmt_key 123
+  msg_ok "Docker + SSH ready"
+
+  msg_info "Creating plant database"
+  pct exec 100 -- bash -c "
+    docker exec hotel-manage-postgres psql -U postgres -c \
+      \"CREATE USER plant WITH PASSWORD '${PLANT_DB_PASS}';\" 2>/dev/null || true
+    docker exec hotel-manage-postgres psql -U postgres -c \
+      \"CREATE DATABASE plant_db OWNER plant;\" 2>/dev/null || true
+    docker exec hotel-manage-postgres psql -U postgres -d plant_db -c \
+      \"GRANT ALL ON SCHEMA public TO plant;\" 2>/dev/null || true
+  " &>/dev/null
+  msg_ok "Database plant_db ready"
+
+  msg_info "Deploying plant"
+  deploy_service 123 "plant" "${REPO_ROOT}/plant" /opt/plant
+
+  push_file 123 /opt/plant/.env <<EOF
+NODE_ENV=production
+APP_SLUG=plant
+DATABASE_URL=postgresql://plant:${PLANT_DB_PASS}@10.10.10.100:5432/plant_db
+CENTRAL_AUTH_SECRET=${CENTRAL_AUTH_SECRET}
+SETTINGS_URL=http://10.10.10.116:3080
+SETTINGS_SECRET=${SETTINGS_SECRET}
+OFFICE_IP_CHECK=${OFFICE_IP_CHECK:-${OFFICE_IP:-disabled}}
+FRONTEND_PORT=3080
+EOF
+
+  local build_out
+  if ! build_out=$(pct exec 123 -- bash -c "cd /opt/plant && docker compose up -d --build 2>&1"); then
+    msg_error "docker compose build failed in LXC 123:
+${build_out}"
+  fi
+
+  msg_info "Waiting for plant"
+  wait_healthy 123 "http://localhost:3080/plant/health" \
+    && msg_ok "Plant Room running at 10.10.10.123:3080" \
+    || msg_warn "Plant Room may need extra time — check LXC 123"
+
+  msg_info "Seeding plant into auth DB"
+  pct exec 100 -- docker exec hotel-manage-postgres psql -U postgres -d auth_db -c "
+    INSERT INTO apps (slug, name, description, base_path, icon, theme_color, category, internal_host, internal_port)
+    VALUES ('plant', 'Plant Room', 'Plant-room equipment monitoring and alerting — boilers, water softener, calorifiers and pumps via MQTT telemetry', '/plant', 'Gauge', '#0e7490', 'Operations', '10.10.10.123', 3080)
+    ON CONFLICT (slug) DO UPDATE SET
+      name=EXCLUDED.name, description=EXCLUDED.description, base_path=EXCLUDED.base_path,
+      icon=EXCLUDED.icon, theme_color=EXCLUDED.theme_color, category=EXCLUDED.category,
+      internal_host=EXCLUDED.internal_host, internal_port=EXCLUDED.internal_port;
+    INSERT INTO app_capabilities (app_id, slug, name, description, sort_order)
+    SELECT a.id, c.slug, c.name, c.description, c.sort_order
+    FROM apps a, (VALUES
+      ('view','View','View the plant-room dashboard and alert list',1),
+      ('manage_assets','Manage Assets','Create/edit assets, alert rules and asset photos',2),
+      ('acknowledge_alerts','Acknowledge Alerts','Acknowledge and resolve triggered alerts',3),
+      ('settings','Settings','Configure plant app settings',4)
+    ) AS c(slug, name, description, sort_order)
+    WHERE a.slug = 'plant'
+    ON CONFLICT (app_id, slug) DO NOTHING;
+  " &>/dev/null \
+    && msg_ok "plant seeded into auth DB" \
+    || msg_warn "Seed failed — run plant/seed-app.js manually"
+
+  npm_add_location "/plant/" "10.10.10.123" 3080
+
+  msg_warn "plant deployed but the shared MQTT broker (LXC 104) is separate infra — telemetry ingestion will retry/backoff until it's reachable and the water-softener (or any other) asset is created with its mqtt_topic_prefix set on the Assets page."
+}
+
 deploy_kitchen() {
   msg_step "Kitchen (LXC 110 · 10.10.10.110)"
 
@@ -2482,6 +2568,7 @@ if [[ "${1:-}" == "--only" ]]; then
     mqtt-broker)     deploy_mqtt_broker ;;
     hvac)            deploy_hvac ;;
     calendar)        deploy_calendar ;;
+    plant)           deploy_plant ;;
   esac
   exit 0
 fi
@@ -2516,5 +2603,6 @@ deploy_kds
 deploy_wages
 deploy_hvac
 deploy_calendar
+deploy_plant
 configure_npm_proxy_hosts
 print_summary