Texas Super-Sweet Onion Sets

Days to Maturity: 105-110

Developed by Texas A&M, the most famous Texas onion, Texas Super-Sweet Onion, an open pollinated variety, is grown as a bulb vegetable. The large, up to 6-inch, globe-shaped bulbs have off-white (yellow) flesh that is very sweet and flavorful. The plant is easy to grow and disease resistant, making it a good choice for beginners. Storage potential is 2 to 3 months. Onions are a good source of folate and vitamin C.

This plant is a member of the amaryllis family (Amaryllidaceae). Typically grown as an annual, the onion is an herbaceous biennial plant with an upright habit of linear, cylindrical, hollow, glaucous leaves that arise in a basal rosette and are typically bluish green in color. The plant has a medium growth rate.

Onions are great companion plants in the garden. They naturally deter certain garden pests, like aphids, Japanese beetles, sugar beet-flea beetles, deer, and rabbits. Onions can also improve the flavor of some of their companions, while some companions, like chamomile and summer savory, can improve the onion's flavor. Scattering them around the vegetable garden helps to produce healthier harvests.

Think of onions as a leaf crop, not a root crop. They prefer full sun and loose, fertile, moist, well-drained soil with a pH of 6.2 to 6.5. A lower or higher pH may result in poor bulb quality or small yields. Short-day type onion varieties are adaptable to southern regions with 10 to 12 hours of day length in the summer. The more sun and space between plants, the bigger the bulb. Onions have shallow root systems and need consistent moisture. Onions are heavy feeders. Adding manure or compost to the soil several weeks before planting (or the winter before) and applying fertilizer when planting and again every two weeks increases plant size and make onions sweeter. And since each leaf represents one ring of the onion bulb, more leaves equal more rings, resulting in bigger bulbs. Keep beds free of weeds, which will compete with the onions for water and nutrients. To avoid disease, practice crop rotation, planting onions in a different location every year.

A cool-season vegetable, Texas Super-Sweet Onion Sets can be direct sown into the garden in fall for a late spring harvest. But they can also be started indoors and transplanted, spring and fall. Planting sets in midsummer will produce a fall or spring harvest. They need cold temperatures to germinate and grow. Plant shallowly and protect plants from heavy frost with row covers.

Harvest onions when two-thirds of the leaves fall over and turn brown. Leave them lying in the garden for 1 to 2 days to dry, if weather permits; continue drying them for 2 to 3 weeks in a cool, dry, sunny location; and once completely dried, store them in a dark, dry environment in mesh bags or crates with good air circulation.

Onion sets are small onion bulbs grown in the previous season. The partially formed bulbets are around ¾ inch in diameter, making them easier to plant than seed. They develop into full-size bulbs quickly after planting, in approximately 3½ months. Sets tend to produce stronger, more vigorous plants compared to seed, ensuring larger yields.