How to Grow Sweet Onions
Sweet onions are one of the easiest veggies to grow, although they take a LONG time to do so. I plant mine in November and can’t harvest until May-June. (Told you it was a long time!) But they are SO worth it. Consumed raw on a sandwich or in a more savory fashion such as baked or sautéed, sweet onions are the bomb.
When it comes to planting onion seeds, I don’t. I go the onion “set” route which means I purchase already “sprouted” onions known as sets. I didn’t have great luck when I tried to sprout my own sets. **sigh** Not everything I try in the garden works out as planned.
My local seed store sells the onion sets in batches of 100 which means come May-June, this gardener is stocked FULL of sweet onions. Makes it a great time to share the wealth of harvest!
I grow red and sweet–both work the same way.
To begin, I form channels down my intended bed. It keeps the process of planting simple and easy–two words I like a lot when it comes to the garden.
Space onions about 3-4 inches apart, the back fill with compost. Onions don’t like to sit in water, so make sure you use a soil that drains well. My compost is perfect!
You’ll need to straighten them out, ensuring each onion set is approximately 1 inch deep. Water well and continue a moderate watering schedule. Remember, onions don’t want to sit in water but they do need it. Their bodies made up mostly of water!
When it comes to fertilizer, give them a serving of fish emulsion once a month, punctuated by the occasional general purpose fertilizer. Beware of giving them too much nitrogen, or you’ll end up with healthy leaves and dismal fruits.
Onions are ready to harvest when most of their tops fall over. Gently pull them from the ground and leave them in the sun to cure for about a week. When the tops are dry and crinkly, cut the tops off about inch or so above the bulbs and store in a cool, dry place.
Scallions are a different kind of onion than sweets with a considerably shorter growth period. Basically, scallions are onions that don’t produce bulbs wider than the leaves. I plant mine from bulbs and harvest when the tops are green. Yum!
Onions don’t have a lot of issues. Like garlic, their pungent smell tends to repel most critters, though nematodes can be a problem. They can also develop a fungus if they suffer extremely moist conditions. Adding horticultural cornmeal to the top of the soil (approx. 1 lb. per 100 sq. ft.) can help reducing nematode populations, as does growing broccoli or cabbage (brassicas), then tilling the green plants under.
Good Companions: Beets, broccoli, cabbage, carrots, cauliflower, kohlrabi, lettuce, pepper, spinach, strawberry, tomato, turnip.
Bad Companions: Asparagus, bean, pea, sage.
Health Benefits: Like their smelly cousins garlic, onions are rich in sulfides and polyphenols. Like garlic, they are beneficial to the cardiovascular system, have anti-inflammatory powers, but can also improve bone density, of particular benefit to menopausal women.