I am not “in the field”, but I am from a farming family and have been gardening pretty much my entire life. I have recently become interested in a couple of technologies aimed at ultra high density production while minimizing water consumption.
The first of these techniques is known as “Aquaponics”, which is a marriage between aquaculture and hydroponics. In short, one sets up a symbiotic relationship between a fish tank and a hydroponic plant bed. The fish fertilize the plants and the plants clean the water for the fish. You get the high crop densities and low maintenance of a hydroponic system, it is 100% organic, and as a side benefit you can also harvest fish as well. Additionally it uses only 10% of the water than does conventional farming because the water is recirculated in a closed loop so the only loss is from evaporation and transpiration.
The second technique is “wicking beds”. These are arranged such that there is a water reservoir under the bed itself along with an integrated worm composer that puts nutrients in the water. Because of the bed arrangement the water is all utilized by the plants rather than running off or soaking down below the where the plants can make use of it.
Use your favorite search engine to find more info on either of these sustainable techniques.
As for cold, can’t really offer any advice. Here in Texas in mid-October my plants were actually showing signs of heat stress last weekend as temperatures climbed into the 90’s.