How do I calibrate the humidity sensor?

Your Grow Sensor is factory-calibrated for high accuracy right out of the box, so in most cases, no additional calibration is needed.

However, if you notice slight variations, calibration can help fine-tune accuracy.

Why not use the salt test?

While the salt test is a common DIY method, it’s notoriously unreliable and difficult to execute precisely.

An inaccurate reference point can lead to incorrect calibration - which may be worse than no calibration at all.

Instead, we recommend using a Boveda One-Step Hygrometer Calibration Kit for the most precise and repeatable results.

How to calibrate humidity using a Boveda kit

1

Place your Grow Sensor inside the calibration bag

Use a Boveda 75% One-Step Hygrometer Calibration Kit, which can be found online for under £10.

2

Seal the bag and leave it undisturbed for 48–72 hours

Keep it in a stable environment with minimal temperature fluctuations.

3

Adjust the calibration in the app

If the reading is slightly off, use the app’s calibration settings to fine-tune it to 75.0% RH.

Pro Tip: Keep your calibration kit sealed when not in use. It can be reused for at least three months to re-verify accuracy.

Important notes

• Only calibrate if necessary – The Grow Sensor is highly accurate out of the box. Adjustments should only be made if a verified reference shows a discrepancy.

• Make small adjustments – Calibration is intended to correct minor variations (typically within ±5% RH). If your readings are significantly off, there may be an issue with the calibration process or sensor.

• Temperature and humidity calibrations are separate – You can calibrate one or both independently, depending on what’s needed.

If you're seeing large discrepancies or need help calibrating, contact us at [e-mail] we’re happy to help!