Howdy,
I’ve decided on the core 3 sensors for growerbot:
- Temperature / Humidity: DHT22. .5C temperature and +/-2% humidity accuracy. Datasheet (pdf).
- Light: TSL2561. .1 to 40,000 lux, with separate sensors for infrared and full spectrum. Datasheet (pdf).
- Moisture: 2mm corrosion-resistant stainless steel rods of consistent length (probably gonna use 1″) mounted a fixed distance apart. McMaster part #1335t21, although I’ve heard I can just use stainless steel TIG welding rod as well…
Here’s approximately what the DHT22 and TSL2561 look like:
and 
For the light sensor, I’m still debating whether to buy the Adafruit breakout (pictured above) or do my first-ever surface-mount soldering with the individual chip instead. Any alternative suggestions for sensors I should consider, please let me know!
Assuming you are self-assembling these, a little practice with a hot air solderIng iron, a hands-free magnifying glass and some solder paste and you’ll be able to solder these in about 30 seconds.
Ph and either TDS or EC inputs would be ideal for automating a hydroponics/aeroponics site.