Some things I've learned since I first installed a Photon system in My granddaughter's 100' x 30' hoop house last summer:
1. The environment is tough. The temperature swing in a single day can be over 50F. Humidity often approaches 100%. UV attacks plastic, e.g.: the heat-shrink tubing over the wire splices.
2. I have wire runs over 70'. I've learned to use only stranded wire: solid conductor can break -- and it has.
3. I used a single Photon ($19) in the hoop. It's backed by a Raspberry Pi 100 miles away. Attached to the Photon are 3 temperature sensors, 2 soil moisture sensors, plus switches for an outside deer fence and irrigation valves: about $90. But the wiring cost more. I should have used multiple Photons and shorter cable runs. More complicated programming, simpler/cheaper cabling.
The Photon has been reliable. Not the rest. For my initial cabling I ran two Cat5 8-conductor cables (solid copper) to the middle of the hoop house and spliced (solder/heat-shrink/non-conductive caulk) 2 or 3 wire cables to the sensors. That failed -- not always hard failed, some intermittent. Been replaced with straight (unspliced, more expensive) runs.