Measure the room before you grow in it

I used to think I could tell what a room was doing by standing in it. I can’t. So before anything grows in a space, I want a few days of numbers from it.

None of this is expert advice. It’s what I plan to do, and why.

Temperature and humidity, in two places

The plan is to log temperature and relative humidity at canopy height and down near the floor, for at least a few days, with the lights and fans running on their real schedule.

One reading tells me nothing. A chart shows when the room drifts, how fast, and usually why. If you want to turn those two numbers into something more useful, the VPD calculator does the math.

Airflow

Dead corners and still air under a canopy are where mold gets started. A cheap check: log humidity in the worst corner you can find and compare it with the middle of the room. If the corner is always wetter, the air isn’t moving there.

Check the sensors against each other

Two cheap hygrometers sitting side by side will often disagree. I’ll check mine against a known reference, write down how far off each one is, and do it again every few months.

Why bother

It isn’t the fun part. It’s cheaper than losing a grow, though, and I’d rather find out the room is wrong while it’s empty.

I’ll post my own room log once the sensors are in.