Although we have to wait before we can enjoy those sweet Vidalia onions, you can use these tips to growing sweeter (or hotter) onions in your own garden.
‘Sweet’ onions are better described as ‘mild’ onions, since the reason for their sweet flavor is the lack of the hot or pungent compounds found in other onions.
To grow milder or hotter onions follow these tips from Extension Specialist Willie Chance.
• Start with the right variety. The varieties grown in the Vidalia area have been selected for mildness. Examples include; Granex 33, Dessex and Savannah Sweet, as well as others. Home gardeners can look for Vidalia or sweet onion transplants in the store or seed catalog. There are many hot onion varieties. For example, the ‘Creole’ types are pungent onions grown in the southern United States. Onions planted in the fall and grown slowly over the winter and spring have the best chance of being mild. However, late winter planted onions can be grown so as to produce a fairly mild onion.
• Sulfur fertilization increases pungency. Avoid late sulfur applications for mildest onions. Sulfur is mainly found in complete fertilizers like 10-10-10, 5-10-15, etc. For fall planted mild onions, apply complete fertilizers up to Feb. 1. For late winter planted mild onions, apply complete fertilizers at planting and for the first sidedress only. After this, later fertilizer applications should be made with fertilizers that contain no sulfur. This would include sodium nitrate (Bulldog soda), calcium nitrate and potassium nitrate.
Apply these at low rates (7 ounce/100 square feet) every three to four weeks or so. Ammonium nitrate (4 ounce/100 square feet) could also be used, but is less desirable. For hot onions, use complete fertilizers for all fertilizations. Stop all fertilizer applications 30 to 45 days before harvest. Harvest is generally around May 1. Always remember that although we want to limit complete fertilizer applications when growing mild onions, we cannot eliminate complete fertilizers from the fertility program or the onions will not grow well.
• Well watered onions are milder. Keep mild onions well watered, especially during blubbing.
• Remember to harvest a few onions to enjoy as green onions. Harvest the remainder for use as dry onions after the tops are fallen and begin to dry. After the tops have fallen, and if it begins to rain, rapidly harvest onions to prevent splitting and rots.
For additional information, contact the Dawson County Extension Office at (706) 265-2442.
Clark Beusse is the Dawson County extension agent.