University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Historical Materials from University of Nebraska-Lincoln Extension Extension 2000 EC00-1207 Growing Onions, Shallots, and Chives Susan Schoneweis University of Nebraska-Lincoln Laurie Hodges University of Nebraska at Lincoln, [email protected] Loren J. Giesler University of Nebraska-Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/extensionhist Part of the Agriculture Commons, and the Curriculum and Instruction Commons Schoneweis, Susan; Hodges, Laurie; and Giesler, Loren J., "EC00-1207 Growing Onions, Shallots, and Chives" (2000). Historical Materials from University of Nebraska-Lincoln Extension. 2012. https://digitalcommons.unl.edu/extensionhist/2012 This Article is brought to you for free and open access by the Extension at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Historical Materials from University of Nebraska-Lincoln Extension by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. University of Nebraska Cooperative Extension EC00 -L207 -B Growing Onions/ Shallots, and Chives Susan Schoneweis, Extension Coordinator for Environmental/Home Horticulture; Laurie Hodges, Extension Specialist-Horticulture; and Loren Giesler, Extension Plant Pathologist The common onion (Allium cepa) is the most popu- often indicates that mechanical damage or decay has lar and widely grown A1lium in Nebraska home gar- occurred. Heat destroys alliinase, so whole boiled on- dens. Many members of the onion family (Alliaceae) ions tend to have little flavor because the flavor precur- are used in flower gardens because of their interesting sors have little chance to react with the enzyme. flowers and foliage, but here we're going to focus on the onion as a vegetable crop. Types of Onions Or:rions are thought to have first been domesticated in the mountainous regions of Turkmenia,IJzbeckistan, Tajikstan and northern Iran, and have been cultivated Onions are often grouped according to taste. The for more than 5,000 years. As people two main groups are the strong-flavored types (American) moved all over the world, the and the mild types (European or Bermuda). onion and its relatives in Generally, the more pungent onions produce the Allium genus or bulbs that are smaller and have a firm or Alliaceae families dense texture and a better keeping moved and quality than the milder, sweeter adapted to their onions. Each type new homes. On- has three dis- ions, garlic and tinct colors - other alliums have yellow, white, been used through- and red. Red out history for both onions have a culinary and medicinai deep red to pur- purposes. Scientists plish-red skin found that the various sul- which makes them fur compounds contained attractive in salads or in onions and garlics that wherever raw onion give them their distinctive rings are used. Sweet on- flavors also have anti-mi- ions, such as the Vidalia crobial and anti-fungal and Walla Sweets, are low properties, giving valid- in sulfur compounds, but ity to their historic me- their flavor may be altered dicinal value. by the soil sulfur level. Whenfreshoniontis- Onions also may be sue is damaged, flavor grouped according to the du- precursors react with the ration of light required to trig- enzyme alliinase and the ger bulb formation - short, flavors and aromas de- intermediate, or long-day on- velop. This is why whole ions. Generally, a short-day onions do not have an odor onion will form bulbs when the until they are damaged. The pres- day length is between 10 and 11 ence of an odor from intact alliums hours long, conditions occurring Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Elbert C. Dickey, Interim Director of Cooperative Extensiory University of Nebraska, Institute of Agriculture and Natural Resources. DU MNE university of Nebraska Cooperative Exteroion ed ,:i5.,il:,ilT'Jilil:'S:;:i*5",::X*'f,lTnation policies of the university of Nebraska-Lincoln in Nebraska in early February. Long-day onions require They are then harvested in the summer and stored for a minimum of 14 hours of daylight before bulbs form. replanting the following spring. The main reason to use In Nebraska, daylight hours exceed the long-day mini- sets is for earliness or to allow mature bulb develop- mum by early May. Since the size of the bulb is directly ment in areas with short growing seasons. Usually related to the number of leaves formed prior to bulb onion sets are labeled by color, not specific cultivar. Sets initiation, long-day or intermediate-day onion culti- can be used for green onions (also called scaliions) or vars are best for Nebraska. can be left to grow for mature storage bulbs. Green Each onion cultivar within a photoperiod group onions can be pulled when plants are 6 inches or taller. (Iong-, short-, or intermediate-day) needs a specific There are also cultivars to grow from seed that will number of hours of daylight to induce bulbing. Once the produce a true bunching onion or scallion that does not daylength (photoperiod) requirement is met, other fac- form a bulb. tors can reduce leaf size and result in premature bulb One disadvantage of planting onions from sets is formation or smallbulbs. These factors include drought their tendency to bolt (form seed stalks) and bloom. To stress, hail damage, insect damage, close spacing, and reduce bolting, sort and select small onion sets, 7/2 to weed competition, arnong others. Although short-day 1/3 inch in diameter from the larger sets. Plant the onions, such as the onion cultivar "Granex33" grown in larger sets (over 3/4 inch diameter) for early harvests of Vidalia, Georgia or the Texas 1015Y can be grown in green onions as they are more likely tobolt if the young Nebraska, it is necessary to plant sets in very early shoots are exposed to prolonged temperatures below February and grow them rapidly to obtain large onions. 45.F. Some Nebraska gardeners have grown these success- Plant onion sets one to tlvo inches deep, close fully by using black plastic mulch or occasionally with- together and thin to 3- to 4-inches apart as r-ou han est out mulch, but it can be a challenge in our climate. green onions. If you don't pian to hart'est green onions, Most cultivars adapted to Nebraska conditions are the initial spacing should be 3 to -1 inches betu'een sets. fairly pungent and generally keep better than the mild, Rows should be 16 to 24 inches or more apart depend- sweet onions produced in the spring. The cultivars used ing on the method of cultivation. For rvide rou'plant- as storage onions are yellow and fairly pungent. The ing, plants or sets are placed on 3 to $inch centers. European or Bermuda onion cultivars are mild and Onions are ideal for wide row planting, but keep in several long- and intermediate-day cultivars are avail- mind that weeding then must be done br- hald. able, such as Sweet Spanish, Sweet Sandwich, Ring- master, and the Walla Walla Sweet. These do not store Plants well but are fine for use within a month or so of harvest. Onion plants often are produced in the south from Growing Onions seed planted in the fall and are usuallv bundled in the field in groups of 50 to 100 plants. Onion. lrom trans- Onions may be grown from seed, sets or trans- plants and seed usually do not form flou'er stalks the plants for use both as green onions and dry bulbs for first year. Garden stores may sell packs of locallr- grown storage. Using onion sets is the easiest way to grow a transplants or you can grow them under plant Lights by crop, followed by transplanting and direct seeding. starting seed in early February. Unlike sets, bundles of Onions are adapted to a wide range of temperatures onion plants are identified by cultivar so vou can choose and are frost-tolerant. Early spring planting is essential the type you want. Garden centers often sel1 short-day because best growth occurs when cool temperatures sweet onion cultivars as well as long-dav srveet and (55'F to 75'F) prevail and several leaves can develop storage onions. For best yields of short-dav cultivars, bef ore bulbing begins. Nebraska gardeners should note transplant them as early as the soil can be rvorked, iate the size, shape and use as described in seed catalogs and February or early March. If transplant roots seem dry, select intermediate- or long-day cultivars when grow- trim them slightly and soak in tepid water for a few ing from seed or transplants. Short-day onions, which hours to re-hydrate them before planting. Set the base often are available as transplants in garden stores, must of the plants 1 to 2 inches deep and 3 to 4 inches apart, be planted very early in order to produce well. lightly firm the soil, and irrigate. Onions gron, w,ell when grown on raised beds mulched with black plastic Sets and using drip irrigation. The plastic mulch not only controls weeds but also raises the soil temperature for Onion sets are small onions grown from seed with more rapid growth and development. Cut holes in the the growth arrested so that it can resume at a later time. plastic, spacing the holes about 3 inches apart. The set Sets often are produced by planting a short-day onion or transplant is then planted in the hole. cultivar under long-day conditions to induce early bulbing. They are planted very thickly to limitbulb size.