6-Probe WiFi Soil Moisture Monitor

Watch six plants at once from your phone. This WiFi-connected monitor tracks soil moisture across 6 seed trays, pots, or hydroponic setups in real time — sending readings to a clean web dashboard that runs entirely on your home network. No app to install. No cloud account. No subscription that disappears in three years. Just plants and data, where they belong.

What’s in the box

• Pre-assembled 6-probe monitor — white enclosure with brass-inserted threaded screws
• 6 silicone-sealed capacitive moisture probes (weatherproof)
• 6 standard 6P6C phone-style cables — 2 m default, custom lengths available
• USB-C power cable (works with any USB-C wall adapter)
• Setup card with quick-start instructions

Setup in 5 minutes

1. Plug in USB-C
2. Connect to “SmartSoil-Setup” WiFi from your phone
3. Enter your home WiFi (and optional MQTT broker)
4. Stick probes in soil, name them in the web UI
5. Open seed.local from any browser on your network

Two ways to use it

Standalone — Web Dashboard

Open http://seed.local from any phone, tablet, or computer on your home network. Live readings, customizable thresholds, per-probe calibration, 2-hour history graphs. No app, no login portal, no cloud service.

Home Assistant — MQTT Auto-Discovery

Enter your MQTT broker IP during setup. All 6 probes appear as Home Assistant sensors automatically — no YAML editing, no integration to install. Build automations like “if Tray 3 < 20%, send a notification.”

Why local-only matters

Most “smart” plant sensors route your data through cloud servers, require a proprietary app, and stop working when the manufacturer pivots. This one doesn’t.

• No internet required after setup — runs entirely on your local network
• No account, no subscription, no telemetry
• Open standard MQTT — works with Home Assistant, Node-RED, Domoticz, OpenHAB
• Open source firmware — you own the device end to end

Perfect for

Seed starting · hydroponics and aeroponics · greenhouse and grow-tent monitoring · indoor garden / shelf-mounted plant collections · bonsai and rare houseplants · mushroom cultivation · vacation plant-sitting

Specifications

• Power: USB-C, 5 V, any standard phone charger
• WiFi: 2.4 GHz (802.11 b/g/n)
• Probes: 6 × capacitive (corrosion-resistant)
• Probe cables: 6P6C phone-style, 2 m default
• Reading interval: 30 seconds (configurable)
• History: 2 hours of per-probe data
• Smart home: MQTT with Home Assistant auto-discovery
• Enclosure: 3D-printed PETG, white
• Hardware: brass-insert threaded screws

Designed and built in Santa Barbara, California

Hand-assembled in small batches by a single maker. If something doesn’t work, you’re talking to me, not a support ticket queue.