Up Your Gardening Game with Sweet Onions

Up Your Gardening Game with Sweet Onions

For many people in the Panhandle, gardening season begins when the weather warms in spring and nurseries start setting out tomato transplants.   While I understand the allure of the yummy summer veggies and spring/early summer are the most traditional times to garden, cultivating a winter garden in the Panhandle unlocks many tasty options.  Among these cool-season garden veggies is a classic southern staple that is among the easiest and most rewarding of all vegetables to grow, sweet onions!

‘Texas Super Sweet’ Onions almost ready for harvest in a Calhoun County garden. Photo courtesy of Joe Leonard.

Sweet onions are very popular in the culinary world for their mild flavor and soft texture and are among the most widely grown group of onions across the world, but the most famous of them, Vidalia’s, hail from Georgia!  Despite its fame, the “Vidalia” onion is actually nothing more than a trademarked name for a specific variety of sweet onion that was bred in Texas (‘Yellow Granex’ and its derivatives), grown in a 20-county region in South Georgia with excellent onion-growing soil, and made famous by excellent marketing from the Vidalia Onion Committee.  While they can’t be called Vidalias legally, you can absolutely grow your very own Vidalia type sweet onions at home here in the Florida Panhandle!

Sweet Onions are most easily grown at home if purchased in the fall as “sets”.  Sets are small bulbs that have been started, harvested, dried to prevent rotting during storage, and shipped to garden centers ready to be “set” out in home gardens.  Sweet onions may also be grown from seed but take much longer and have a lower success rate.  When browsing onion set varieties for purchase at garden centers or in seed catalogues, make sure to purchase a short-day “Granex” type like “Texas Super Sweet” or similar.   It is critical to remember that sweet onions are classified by how many hours of daylength they require to produce bulbs.  The three classifications are Short, Mid, and Long-Day.  Since sweet onions require cool weather to develop properly, Floridians must grow short-day varieties to compensate for decreased daylight hours in the winter.  In the less hot Northern states, long-day sweet onions are grown in the summer, where they’ll be able to soak up 15-16 hours of daylight.  Therefore, for best results in the Panhandle, select ONLY short-day onion varieties.

‘Texas Super Sweet’ Onions that have been harvested and are ready for use! Photo courtesy of Daniel Leonard.

Once you’ve selected your onion sets in the fall, they can be planted in the garden anytime from early October to mid-December.  Individual bulbs should be planted about an inch deep in well-drained garden soil with high organic matter content (mushroom compost, composted manure, or other rich organic matter works) and spaced 4-6” between plants and about a foot between rows.  Onions in general, and sweet onions in particular, are heavy feeders and require ample nutrition to meet their potential!  To meet these fertility needs, I apply a slow-release fertilizer like Osmocote or a Harrell’s product at planting and supplement that with either a quick release granular or liquid fertilizer monthly during the bulb enlargement phase.  Sweet onions also have a shallow root system and require frequent watering to develop properly and avoid splits, doubles, and small bulbs.  Don’t let your onion bed dry out!

Finally, sweet onions planted in late fall/early winter are normally ready to harvest in April and May.  However, rather than relying on a calendar, begin harvesting your onions when the tops start to turn yellow and fall over, this indicates maturity.  After harvesting, allow your onions to “cure” with tops and roots still attached for a couple of weeks outside in a shaded, protected area.  Once they’ve had an opportunity to “cure”, remove tops and roots and store the cured bulbs in a cool, dry place (a dark pantry in an air-conditioned room or the refrigerator crisper drawer work fine) and use at your convenience!

While they can’t be called Vidalias, sweet onions grown at home are oh so rewarding and very tasty!  Provided they are planted in quality soil, receive plenty of water and fertilizer, and are harvested/stored correctly, sweet onions will provide a delicious, home-grown culinary treat throughout the year!  For more information about growing onions in the home garden or any other horticultural/agricultural topic, contact us at the UF/IFAS Calhoun County Extension Office.  Happy Gardening!

Onions: Taste Good, Easy to Grow, and Many Varieties from which to Choose

Onions: Taste Good, Easy to Grow, and Many Varieties from which to Choose

Onions are simple to grow and take up very little space.  This is an easy selection for a beginning gardener.

Onions are simple to grow and take up very little space. This is an easy selection for a beginning gardener.

The winter weather is finally giving way to springtime. While temperatures have been erratic, the rain has been sufficient.
There are still plenty of cool season leafy garden crops in production, but they will not last long as the temperatures rise.

One in-ground selection does offer some options. Onions planted last fall provide the greens and the bulb for a nutritional flavor enhancer from salads to a variety of dishes.

The common onion, Allium cepa, has many varieties within the species, and is grown and consumed worldwide. Garlic, chives and leeks are in the same genus as onions with their use similar to onions, but not nearly as frequent.

This popular and simple to grow fall vegetable easily handled the harshest north Florida winters. The multiple mornings of subfreezing temperatures and hard frost had no appreciable effect on this versatile vegetable.

Most regional soils can provide a good growing medium for onions. The lack of sulfur in the dirt and the excellent drainage are two requirements for producing a potentially mild bulb, depending on the cultivar planted.

The high levels of available phosphate in most soils also are an advantage when growing onions.

The Granex yellow onion cultivar is likely the current favorite among many gardeners. This is the same cultivar which produces some the premium branded mild onions on the market today.

Onions can be planted from August to March, either by seed or bulbs. Two inch spacing between plants provide enough space to grow and does not waste limited cultivation area.

Days to harvest depend on how the onion is to be used. Green onions, sometimes known as scallions, take four months with bulb onions taking five months or longer.In reality, onions are biennial but are usually grown as annuals.

Historical evidence of onion usage dates back 7,000 years to the Bronze Age. It is uncertain if these bulbs were cultivated or collected in the wild.

Their ease of transportation, long shelf life, and many uses made them an ideal candidate for long distance travel and trade in the days before refrigeration and high-speed movement of vegetables. Every culture and nation has its own special uses for onions.

Today’s onions provide the consumer with a combination of excellent nutrition, and good storage and handling qualities while enhancing the flavor of many meats, vegetables and salads. The bulbs come in three colors (red, yellow and white) which add to the visual quality of the dining experience.

Onions deliver vitamins B-6, C and Folic Acid. They are naturally low in sodium and fats, and contain four percent sugar.

Onions have compounds such as favonoids and phenolics which have had numerous positive health benefits attributed to them. Their consumption can be part of a healthy diet.

Properly handled onions have a potentially long storage life. Store in a cool, dry, well-ventilated area with 45 to 55 degrees the ideal temperature range.

To learn more about growing onions grown in north Florida, visit your UF/IFAS County Extension office or read the Florida Vegetable Gardening Guide.