Interesting question. I've seen man made caves in Finland, where they had them against animals, frost in winter and heat in summer. And we have them in France for cooling wine. Of what i understood the underground temperature is stable because of the insulation the ground offers, but is still dependent on the seasonal differences and average temperature year round. So it will be cooler underground during a heat spell, but warm during a colder period.You could dig a hole and measure or look for a cave on hikes and pull out the thermometer.
Or check this link out, they're cooling onions!. Low tech refrigerating is the search term i used.
Location: Bamako, Mali
posted 2 years ago
The link is very inspiring, I will try this technology as soon as possible!
Cave temperature (and the temperature of spring water coming out of the ground) is the average temperature of the region. This temperature can be below freezing in parts of northern Canada to room temperature in tropical regions. Caves and root cellars are especially useful for food storage in regions with a seasonal temperature change where the cave temperature is frostfree and in a range conducive for food storage. Cave humidity can vary depending on the outside relative humidity, how much cooler the cave temperature is below outside air temperature, and how much water is dripping in the cave. The main advantage of a cave for food storage in tropical regions is that it provides a stable temperature and humidity compared to an above ground room.
I was wondering if chives wouldn't grow all year round in a tropical climate? It's not the same as onions for sure, but maybe easier? And i got this Chinese garlic growing, grows like chives, just cut some leaves and add to a salad, it's lovely.
There are lots of things i can't grow here in France, and people are dragging food all over the world. I try to be conscious about that when shopping and look for local substitutes.
Story like this gets better after being told a few times. Or maybe it's just a tiny ad:
2020 Permaculture Design Course for Scientists and Engineers, June 14-27