Bulb onions are vegetables I consider a must have for the table, are currently available at local outlets as starts and can be planted through early February. Bulb onions (Allium cepa) span ancient to modern times in cultivation. They are determined to be domesticated from central Asia and eventually distributed globally by trade for their unique size and piquant presence. Historically, members from the Columbus expeditions cultivated bulb onions in Hispaniola as early as 1494, introducing a commodity that became well established as a staple in North America by the nineteenth century. Keep in mind that different species of wild onions were present and were in use, such as widespread Drummond’s onion (Allium drummondii) and Meadow garlic (Allium canadense).
The bulb of the onion is a storage organ for the plant. The bulb produces a fan of hollow, blue-green leaves that facilitate photosynthesis. Each leaf is associated with the inner ring of the bulb, so when you laterally cut open an onion you see rings that are made of fleshy modified leaves, collectively acting as the storage organ. Bulb onions enlarge and form in response to specific day length and temperature, identified as long day and short day onions. Long day onions like yellow Sweet Perfection, white Sterling or red Tango varieties form bulbs with day length greater than fourteen hours, while short-day varieties like yellow 1015 Texas Supersweet, or Sakata Red require up to twelve daylight hours. There are additional short-day onions available on the market, such as hybrid Southern Belle Red with an advertisement claiming it to be the sweetest of the red varieties and producing a 4-inch diameter bulb. Yellow Granex produces a semi-flat, sweet varietal up to 5-inch diameter. And Texas Early White is sweet with a rounded bulb finishing out at 6-inches. Each can take up to 110 days to harvest.
Because onions have a habit of bolting when ambient temps become too hot, for our region it is best to garden with short day varieties by transplants in fall or late winter. The transplants, or starts, take on the form of a miniature scallion and are often purchased in a gathered bunch of around 30 to 40 plants. Ensure to plant them with full sun exposure in well-draining sandy or loamy soil, and in beds raised 6 to 10-inches high. Final bed prep should include about 3 pounds of balanced fertilizer (10-10-10) over 100 square feet of garden area mixed within the top 3-inches of soil. One can cultivate onions from seed; however, it will take longer to cultivate to harvest, and you will learn the virtues of becoming a patient gardener and gain practical experience as you care for the plant from seedling to bulbous pearls. For the future, plant seeds 1/4 –inch deep and 1-inch apart October through December. Thin the row to one plant every 3-inches when developing leaves are about 6-inches high. For this time of the year, onion sets are available from local feed stores or garden centers starting around early November to early January. For transplants, plant at 3/4 –inch deep at 3-inches apart.
Caring for the plants include keeping the garden bed free of weeds that will compete for natural resources and impact the size of the developing bulb. Remember that each onion leaf is part of a ring within the bulb, and providing adequate nutrients, water and eliminating weeds will support bulb development for a bigger onion. Apply another round of fertilizer when the plants form 6 leaves, about 1/2 cup for each 10-feet of row, spread evenly between the rows and water in the product. Water evenly and as the soil begins to dry. Whether planted by seed or set, bulbs will be ready for harvest about early May. Harvest when the leaves begin to fall over, then leave in the garden to dry for up to two days. Remove the tops and roots and allow them to continue to dry and paper up in well-ventilated boxes. You can then store the cured onion bulbs in your refrigerator crisper or in a wire or ventilated mesh bag in a cool garage or utility room.
Growing onions to harvest can be a rewarding experience, and I look forward to the time I can bake my red onions with summer squash and a hint of parmesan cheese. I invite you to explore more information about growing vegetables from Aggie Horticulture online: aggie-horticulture.tamu.edu or from our Brazos County Master Gardener website: txmg.org/brazos. Happy New Year, remember we will be friends when we meet and I will see you in the garden.
