Texas AgriLife Extension Service -Denton County

                                                                                                                                   306 N. Loop 288, Suite 222

                                                                                                                                     Denton, Texas 76209-4887

January 15, 2008

ONIONS BEST PLANTED EARLY

 Contact:  John N. Cooper, County Extension Agent-Horticulture, 940.349.2883

  e-mail: jn-cooper@tamu.edu

           Onions are among the most popular vegetables grown today. They are as contemporary as the fajita and as pervasive as the hot dog. You might think Americans invented them but archeological digs in Egypt indicate they were venerated for their health-giving properties by the royalty of the Nile 5,000 years ago.  Although they originated in Mesopotamia, the Greeks and Romans cultivated them widely throughout the Western world.

          Texas ranks first in onion production among the United States. Although commercial onion acreage is centered on the High Plains near Lubbock, our climate is quite suitable.  North Central Texas including Denton County was once a major center for commercial onion production but rainfall interfered with harvests forced the industry to the more arid High Plains half a century ago.

          Onions are one of the most versatile of all garden crops.  They can be eaten fresh or fried, baked, stewed or grilled and used in dips, salads, casseroles and sandwiches.  Although they are only average among vegetables in nutrient value, the green tops are high in vitamin A.  Bulbs can be stored for 3 to 6 months under cool (32- 45 degrees F.), dry conditions.

          Onions are among the earliest spring vegetables to plant.  They make an excellent balcony garden crop.  Space-wise, onions are hard to beat with a pound of groceries produced per square foot planted.  Grow them in containers with a high organic matter potting mix and grow the biggest bulbs on the block.

          Onion transplants are best set out from transplants from mid-January through mid-February.  For yellow bulbs, plant Texas Super Sweet (a.k.a. Texas Grano 1015Y), Texas Grano 502, Excel, Granex, or Granex 33.  For red bulbs, plant Burgundy, Tropicana, Red Grano and Red Granex.  For white bulbs, plant White Grano, Eclipse, Majesty, and White Granex.  For green onions, plant Evergreen Bunching, Beltsville Bunching, and Crystal Wax.  Buy pencil-size or smaller transplants. Transplants larger than 1/4 inch in diameter are likely to “bolt” (go to seed), turning bulbs bitter, a very common and great source of disappointment.

          Onions form bulbs in response to day length.  As days lengthen in the spring, basal stems begin swelling, creating a bulb.  The eventual size of an onion bulb depends on the number and size of the leaves when bulbing starts.  Each onion ring is attached to a leaf.  The more leaves an onion has, the more rings it will have.  The larger the leaves are, the plumper the rings will be.  Getting an early start and providing good fertility and water management are keys to larger bulbs.

          Onions respond well to organic matter.  Spread 2 inches of well-rotted, finely-screened compost over the soil surface and till to a depth of 4 to 6 inches.  Form 18 inch wide raised beds 6 inches high.  Plant transplants 3/4 inch deep every 3 to 4 inches in double rows 1 foot apart on raised beds.  Square-foot and patio container gardeners set plants solid on 6-inch centers or plant them closer, up to 2 inches apart and thin them to eat as green onions as they grow and crowd.

          Onions are heavy feeders so apply 1/2 cup of ammonium sulfate or equivalent per 10 square feet three weeks after setting transplants and repeat the application when bulbing begins.  Onion roots are shallow, so weed by hand and water every week.  Use an organic mulch such as oak leaves to maintain even moisture and reduce weed competition.

          Harvest onions when a majority of the tops wilt, fall over and begin drying in the early summer.  Pull them with the tops on and store them in a cool, dry place until ready for use.  The dry outer leaves should be left, intact, to keep the bulb inside, moist and protected.  Breaking tops over does not speed maturity and may actually reduce bulb quality.

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The information given herein is for educational purposes only.  Reference to commercial products or trade names is made with understanding that no discrimination is intended and no endorsement by the Cooperative Extension is implied.

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Extension programs serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability or national origin. The Texas A&M University System U. S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating.