Having a cooler greatly increases farm efficiency as a whole. It allows for me to harvest and pack produce the day before delivery and keep it cool and fresh. Being able to refrigerate the boxes themselves is also a big advantage as this helps keep the veggies cool when they are on the road.
In the future farm-of-my-dreams I would like to have a full size walk-in cooler. Time constraints this year meant compromise and so I ended up building a large cooler in the basement of the house. It's more than enough for this season as I'm starting out small but in a few years I'll have to re-evaluate. Fortunately, all the equipment in the current cooler can be reused someday when I build the walk-in version.
The design for this cooler came from Ron Khosla, a fellow electrical engineer turned farmer. The basic idea is to force a compatible air conditioning unit to continue to cool below it's standard range. It's called the Coolbot and it's connected it to a simple window air conditioning unit as pictured above. The two devices, along with a wood frame and some polystyrene make up a very effective and energy efficient cooler. If I were to buy a pre-made cooler of this size I would have easily spent 10-20 times as much. I feel like there some harmony between the engineer's need to tinker and re-build and the farmer's desire for self-reliance and independence. In other words, farming is a good way to support my DIY habit.