GnodeHub 🌱

Values

Everything below is a calibrated estimate from consumer-grade sensors, not a lab measurement. Treat the trend over time (rising, falling, holding steady) as more meaningful than any single exact reading, and use your own judgment about your plant alongside it.

• PPFD (µmol/m²/s): Photosynthetic Photon Flux Density, measuring light intensity for photosynthesis.
• Lum (lumen): Luminous flux in lumens, measuring total visible light.
• Lux (lx): Illuminance in lux, measuring light intensity per unit area.
• Gas Resistance (kΩ): Gas resistance in kilo-ohms (kΩ) from the BME680's built-in VOC sensor -- not a concentration of any specific gas like O2. The sensor heats a metal-oxide element and measures how its resistance shifts as airborne volatile organic compounds (VOCs) interact with it: cleaner air reads a higher resistance, while more VOCs (off-gassing, mold, rot) pull it lower. Best read as a relative day-to-day air-quality trend for a plant's environment, not an absolute measurement.
• Temp (°C): Temperature in degrees Celsius. Shown alongside Humidity because together they determine VPD (see below) -- the real driver of how fast a plant gains or loses moisture, not just two unrelated numbers.
• Humidity (%): Relative humidity in percentage. Shown alongside Temp for the same reason -- see VPD below.
• Pressure (hPa): Atmospheric pressure in hectopascals (hPa).
• Soil Moisture (%): Soil moisture level as a percentage, from a capacitive soil probe. Readings shift with soil type, potting mix density, and exactly where the probe sits in the pot -- useful for spotting trends (drying out, freshly watered), not as an exact lab-grade percentage.
• Soil Moisture Category: A categorical classification of soil moisture level (Dry, Moist, Wet) based on the percentage.
• VPD (kPa): How much "pulling power" the air has on moisture in a plant's leaves, combining temperature and humidity into one number. Low VPD (humid air) means the plant loses moisture slowly, but mold/rot risk goes up; high VPD (dry air) means moisture is pulled out faster, which can stress or wilt the plant. The default ideal range shown on this dashboard, 0.4-1.6 kPa, is a general comfort band for most houseplants -- each plant's Edit panel also has a Humidity needs setting that narrows or widens this band for dry-preferring (e.g. desert/succulent) or humid-loving (e.g. fern/orchid) species.