Here we have a great visual of onions that will keep and onions that will not keep or store well. Both onions look good, nice size, shape or form. But notice that the white onion has a very shrunken stem or neck and the yellow onion has a nice fat strong green stem and neck. The fat stemmed yellow onion will not keep well. Once you cut that stem off, it will sprout a new growing shoot, and get soft and mushy. Why did the white onion end up with the shrunken stem that will allow it to sit dormant, not re-sprout, and therefore store well?
Here comes the onion 101; Onions are day length sensitive. What does this mean? Well in the northern United States at summer solstice they have a pretty long day, lots of light. In the southern United States, they do not have such long days of light. The onions get triggered to bulb up by the amount of day light, so there are 3 types of onions you can buy, either as seed, or starts. Long day length onions, like the classic Walla Walla onion that does well in the Pacific Northwest, Short Day length onions, like the Vidalia that do well in Georgia or Texas, or a Day length neutral onion.
Add to this mix the choice of onions, sweet, storage, red, white and yellow and you get a lot of choices going on. To narrow your choices, first choose an onion that suits the day length of your climate. I can only choose Day Neutral onions. Nothing else finishes here in Taos at latitude 36. If I still lived in Oregon in the Willamette Valley, I would choose a long day length onion at latitude 45.
Once you choose a good onion for your location, it can be pretty easy to grow, harvest and store a nice big 50 lb sack with a 100 or so onions. Start your own onions from seed in late January. I start mine in square flats, about 16 inches by 16 inches. You can sprinkle a generous amount of seed onto the flat, since you can plant them out in March or April, they can stand some crowding. I put 30 to 50 seeds in the flat. Or it is getting easier to purchase good onion starts from seed catalogs.
Onions will tolerate a lot of cold weather and still produce a good crop. If it drops into the teens too many nights, they can get stressed, and the result is that the onion sends up a seed stalk. You can still eat these onions, but they will not keep or store well. I usually plant my onions out in April, but we have cold springs here in Taos. I think March would be fine in many locations.
As the onions finish, make sure to cut back the water. If you keep the soil too moist, your onions will end up with various molds and fungus, once again ruining their keeping qualities. I sometimes leave mine in the field for several weeks at the end of the season with out irrigating them. Onions will develop more of a papery skin as they cure after harvesting. I put mine in re-used onions sacks that I get from the local grocery stores, or restaurants. I like to leave them out on a rack for a few weeks before bagging them for storage. This process also gives me a chance to inspect the onions, sorting out any that have nicks or soft spots, or discolorations. I still use these onions, but I use them up first as they do not keep as well. Onions keep well in a colder place, 32 to 36 with low humidity is the ideal.
I do not do anything special or different to the soil that I plant onions into. I add good quality bio-dynamic compost that I make to all my garden beds. It can give you a good head start if you add the compost to the bed for your onions in the fall. This way if you have a wet or difficult spring, your planting site will be ready. Onions do need to be kept clean and free of weeds in order to get big.
I love a good onion soup, and years ago I found a recipe in the Miso Cookbook that is so easy and delicious. I will share it with you here:
ONION SOUP RECIPE
Get a heavy bottomed pan, I use a cast iron pot. Add a few TBSP of oil, I use olive oil. On a very low heat, add several onion sliced thinly. About 3 cups worth on onions is a good amount. Sprinkle with a 1/4 tsp or less of salt. Stir the onions occasionally , maybe you can wash the dishes, or make a batch of corn bread, or put some squash to bake while the onions cook slowly. After the onions are all translucent and starting to brown add water. 1 to 2 quarts, bring to a boil, turn down to a simmer and let cook for 30 minutes to 1 hour. Put a generous TBSP of a good miso in each individual soup bowl, ladle the soup in and smash or mix up the miso. Add more miso if you like more of a saltily taste. You can also add the classic croutons and cheese to the top too!
