it will work but will need to prevent the aaircondition coils from freezing up

search the web i know mother earth news had plans once
a warming circuit for the coils cycles on oand of
will work can be done

One thing to keep in mind regarding air conditioners is that they pull the humidity out of the room's air. The poor air conditioner will be running all the time just to counter the humidifier. I suggest using a swamp cooler instead. They are used in the arid Southwest more often than air conditioners because they both cool and humidify the air, plus they are cheaper to run than a conditioner. Running both an conditioner and a humidifier will probably cost three times as much as any saving you get from extra cool storage space. Have you thought of a root cellar? Yes, it is a excavating the hole, but it is free to run and it is automatically humidified.

be prepared for sweating produce when you display it at the market.

Below is a link to an article on post harvest handling of produce. There are also plans to contruct a cooler/cold room.

Here is a link that might be useful: post harvest info

Starwoodfarm, the cost of electricity for air conditioning could be prohibitive unless you are dealing in a high-value crop with a good market.

Commercial walk-in coolers are nice but we've never considered them affordable. Trying to build the equivalent as a do-it-yourself project is a possibility and if any group can provide good advice it would be the folks at the Center for Appropriate Technology that Ponderguy provides the link to.

We have a direct-marketing friend with nearly 10 acres in mixed vegetables. That much ground may have a need for more than just a regular walk-in and theirs gets an amazing amount of use. In our little operation, we get by with 2 refrigerators and a train-load of coolers.

Out here in the Wild West, we enjoy some of that arid climate Loodean was commenting on. If you don't have low humidity where you are - better not think too much about a swamp cooler. Even here, pulling temperatures down a whole heck of a lot just with evaporation wouldn't work real well.

One thing some orchardist friends have been able to do is cover a small shed with burlap and set a lawn sprinkler on top of it. Evidently, it is not much more than a big wooden box. Evaporation from the wet burlap covering it must do fairly well at keeping the interior of the shed cool during really hot weather. Don't know for sure because I haven't checked it out but they've been using this approach for years.

Steve

Thank you all for the help and ideas. You've given us many ideas to research to find out best option. Isn't this fun!