Are you sure that is the case for hydroponics? It would be surprising to see a startup with some big names behind it advertise bald faced lies. Or would mold inhibiting compounds not be classified as pesticides?

Any greenhouse environment, hydroponic or not, tends to require high fungicide and insecticide inputs -- at least eventually -- because it's essentially an all-you-can-buffet for pathogens. You could be fine, even excellent, at first, but with no competition or diversity to head them off, pests can cause extensive damage once they get into the system.

It is true with integrated pest management and careful observation you can be a little more calculated and strategic in a closed environment. Until something comes in on your shoe, or blows in through a door left open...

(Took greenhouse mgmt courses before, though I've never worked in the horti industry)

When you're serious about growing a cash crop indoors(i.e. marijuana), you basically have an airlock. No unfiltered air exchange. No outside clothes or footwear. You also have control of the environment and can regulate humidity to help control fungus. When something does get inside, you potentially scrap the crop, sterilize, and start over. I don't know anything about these robotic grow ops, but I bet they do something similar.

This isn't like growing in a greenhouse where you use screens to keep out bugs.

Ah I see, so for the claims to be credible in the long term they would have to operate it like a chip fab clean room. That does sound quite expensive, thorough decontamination of all personnel, air filtration, etc... I’d be curious if they could keep truly keep that up and make profits.

They can't use UV for that?

They can, but it's self-limiting in that all you're really doing is supplying an evolutionary pressure that results in UV-tolerant fungi/pathogens.

I once toured a (large) malting works where the soak-tanks are bathed in UV all the time (except when humans need to enter the room) and harsh chemicals are employed constantly to limit fungal and bacterial growth. They are still unable to eradicate those pathogens and suffer constantly from infection problems.

I would think proper humidity control would be most beneficial. Also this set up looks completely modular and you saw the robot arm adding a rack. Each section could be sterilized and put back into production reducing likelihood of mold and if you found mold could remove the effected sections only. With good climate controls and procedures I believe mold could be mitigated.