James E Boudreaux,1 Hugh Paul Funguy 2 Harriett Green3 and Arthur Lirette4
Louisiana vegetable growers only grow a minimum amount of onions. The onions are grown from sets purchased from nurseries specializing in growing onion transplants. The plants are transplanted into the field in December and January. The majority of the Louisiana onions are grown on plastic mulch with drip irrigation. Just a few of the onions are grown on bare ground. The onions are harvested and sold in farmers’ markets and roadside stands. Onions provide a cash crop during April and May, when few other items are available to sell. They also can be sold out of storage for June and July along with other spring vegetables.
Louisiana growers like onion varieties that are early-maturing, large in size (Colossal -- 3¾”+ -- and Jumbo -- 3 to 3¾”), flat (Granex) to globe in shape (Grano), do not bolt, make few double bulbs, taste mild and store well.
Twelve onion varieties were planted in replicated plots at the Burden Research Center, Baton Rouge, La., in January 2008. Plants were obtained from Bland Farms, Glennville, Ga., Dixondale Farms, Carrizo Springs, Texas, and Dietrich Gembler, Knippa, Texas. Six varieties were only grown in observation plots because of insufficient numbers of plants to include in the replicated plots.
The plants were spaced 6 inches apart on a bare ground row with two drills per row. The plants from Gembler and Bland Farms were planted first on January 17, 2008, with the plants from Dixondale planted later on January 24, 2008. The different time of delivery and the condition of the field prevented all the plants from being planted at the same time.
Weed control is one of the bigger problems for growers of onions. This is because of the development of both winter and summer weeds during the production of the crop. The herbicide Goal (1½ pts/acre) was used as an after-transplanting treatment to control winter weeds. The plots were cultivated several times to control weeds. Prowl (1½ pts/acre) was applied as a layby treatment to the middle of the rows on March 20, 2008, to control summer annuals. The plots were quickly hoed by hand several times to catch the weeds, mostly pepper grass that escaped the herbicides.
The onions were evaluated in the field on May 8, 2008, for maturity, yield, bulb size, shape, degree of bolting, degree of doubles and taste.
The onions were lifted when more than half of the different onion varieties showed signs of maturity (40-50% of the tops have fallen over) on May 9, 2008. The lifter blade passes under the row of onions to break the attachment of roots from the soil. This speeds up the drying process. The use of the lifter blade also loosens the plants from the soil to make harvesting easier. The lifted onions were allowed to dry in the field for 3 days before harvesting.
The plots were harvest on May 13, 2008. Hugh Paul Funguy, Harriett Green and Arthur Lirette drove from Terrebonne and Lafourche parishes to help with the onion harvest. Without these experienced volunteers, the plot would never have been harvested.
The onions were pulled from the row and trimmed with pruning shears. The roots were trimmed close to the bulb, while the tops of the plants were cut an inch or so above the bulbs. The bulbs were separated into different size grades at the time of harvest and were dumped into large burlap bags and allowed to dry overnight in the field. The sacks of onions were picked up and brought to a barn the next day. Heaters and shop fans were used to warm and circulate the air to encourage drying and curing. The onions were weighed and sacked in mesh bags on May 23, 2008, after 10 days in the barn.
Samples of each variety were placed in mesh bags and stored at 700F. The conditions of the bulbs were evaluated on August 11, 2008, 80 days after harvest.
The yields of 12 varieties of onions appear in Table 1. The top-yielding onion varieties in the test were White Granex, Yellow Granex, Texas 1015, Candy, Superstar and Century.
White Granex is a short-day white onion from Gembler and had very good yields of jumbo and medium-size onions. It is early in maturity and globe shaped with very few onions bolting in the test. It had a mildly pungent taste and stored in good condition.
Yellow Granex, a short-day yellow onion from Dixondale, was second with very good yields of jumbo and medium-size onions. It is mid-season in maturity and flat in shape, with little bolting and a mildly pungent taste. It stored in a good condition. Yellow Granex is one of the more popular onions varieties with Louisiana growers.
Texas 1015 (Dixondale) is a yellow short-day onion with an early mid-season maturity. It had very good yields of both jumbo and medium-size onions. It is globed in shape, with only a few bolted plants in the plot. It had a pungent taste and came out of storage in only fair condition.
Candy (Dixondale) is a yellow intermediate-day globe-shaped onion that had very good yields of jumbo-size onions. It is late in maturing and had very few bolted plants and a mild taste. It came out of storage in poor condition. Candy is a popular variety with Louisiana growers.
Superstar is a white intermediate-day, late-maturing onion from Dixondale. It had very good yields of both jumbo and medium-size onions. It is globed in shape with few bolted plants and a mildly pungent taste. It stored in a good condition.
Century, an early mid-season, yellow, short-day onion from Bland Farms had very good yields of both jumbo and medium-size onions. It is flat in shape, had bolted plants in the plot and a mild taste. It came out of storage in very poor condition.
Two of the varieties, Cebolla and Georgia Boy, stood out in the observation test. Cebolla is an early-maturing, yellow, globe-shape onion that had good yields of medium- and jumbo-size onions. It had only a few bolted plants with no double bulbs. It had a mild taste and came out of storage in good condition.
Georgia Boy is an early-maturing, yellow, globe-to-flat-shape onion. It had no bolted plants and no double bulbs. It had a mild taste and came out of storage in good condition.
Growers are encouraged to make small planting of these varieties of onions to see how they perform under the conditions of their farms.
1Professor, LSU School of Plant, Environmental and Soil Science, Baton Rouge, La.; 2Vegetable Grower, Bayou Blue, La. (Retired Agronomist, USDA Sugar Cane Research Station, Houma, La.); 3Volunteer LaTerre Master Gardener, Houma, La.; 4Vegetable Grower, Raceland, La.