Calibrating those sensors ? That is almost never done. Buy a good sensor.
Calibrating it could improve the accuracy, but that is not easy. Using the calibration from the manufacturer is easier and might even be better.
The DHT22 is not good.
The placement of the sensors is important. Out of the sun; in a box; the box out of the sun as well; a open box, but no water that could drip into it.
Here is a extensive test: https://www.kandrsmith.org/RJS/Misc/Hygrometers/calib_many.html.
Here is a extra super extensive test: https://forum.arduino.cc/t/compare-different-i2c-temperature-and-humidity-sensors-sht2x-sht3x-sht85/599609.
Is there a test that says something about being in a high-humidity environment ? I think that 60-90% is not extreme, that should be no problem.
How are you going to wire those sensors ? With a cable ? With a few hundred Arduino board ? Who is collecting that data ?
Is there air blowing in the glasshouse ? Then perhaps one sensor per section is enough.