Horticulture : News
DATE: January 30, 2012
HARDIN COUNTY COOPERATIVE EXTENSION SERVICE
201 Peterson Drive
Elizabethtown, Kentucky 42701-9370
BY: Amy Aldenderfer
County Extension Agent for Horticulture
Planning an Onion Crop
Although we’re in the midst of winter, it is never too soon to think about next growing season. This is particularly true if you want to grow onions.
Onions are a good crop for Kentucky farmers. Typically in late winter it takes eight to 10 weeks to produce a reasonably sized transplant. If you want to plant in late March or the beginning of April, you should seed your transplants in late January. If you have not already started your seeds, it’s not too late for an onion crop this year. You can purchase transplants or sets from a reputable dealer.
Onions will bulb in response to day length. Short-day varieties need 11 to 12 hours of sunlight per day to bulb, intermediate-day varieties bulb with 12 to 13 hours of sunlight, and long-day varieties bulb with 13 to 14 hours.
Be sure to buy intermediate day-long or day-neutral onion varieties. Why? If a line were drawn between San Francisco and Washington, D.C., residents on the north side would grow long-day onions while those living on the south side would rely on the short-day onions for best results. Most seed catalogues indicate (S) short or (L) long-day types.
Short-day onions develop bulbs in no more than 12 hours of daylight. Consequently, in the north where summer days are longer, these plants form extremely small bulbs prematurely.
Long-day onions require 14-16 hours of daylight and thus fail to form bulbs under short-day conditions. Those areas that lay along the line (Kentucky) can also grow intermediate day-length varieties (13-15 hours). These are planted in the fall and mature after short day varieties in the late spring, early summer.
The types of onions grown during the winter in the Deep South, such as Vidalias, are short-day types. Unfortunately, Kentucky is far enough north that if planted here short-day onions will bulb very early in the spring when plants are still small. The result will be small golf-ball or tennis-ball size bulbs.
Instead, try to buy intermediate-day types such as the popular “Candy” onion. These will begin to bulb in mid-May and should mature by early- to mid-July.
Many growers report bulbs the size of softballs when growing “Candy” onions. If you decide to plant a long-day variety, such as Walla Walla or Sweet Spanish, your plants will begin to bulb in June and continue until early August when they will be mature. Although long-day types yield well in Kentucky, high summer temperatures may lead to an increased disease risk.
For more on growing onions and other vegetables, contact the Hardin County Cooperative Extension Service by phone: 270.765.4121, email: Amy.Aldenderfer@uky.edu or on the web: www.hardinhort.org. Educational programs of the Kentucky Cooperative Extension serve all people regardless of race, color, age, sex, religion, disability or national origin.
NOTE: The Gardener’s Toolbox Series is continuing with:
The “How to Grow” classes are 1 hour long discussions on growing conditions, nutrients, and varieties on a particular group of food plants.
How to Grow: Potatoes - February 20 Have you eaten a fresh potato? You are missing out if you don’t grow your own. Potatoes are easy and there are more varieties than russet and Yukon gold. We’ll explore varieties, growing challenges, and cooking tips.
How to Grow: Carrots - March 5 Did you know that everyone can grow carrots? There are long ones, short ones and even carrots that aren’t orange! Learn all about the lowly carrot and the exciting new varieties, how to grow them in Kentucky clay and the best recipe ever!
How to Grow: Lettuce - March 21 Have you eaten your greens today? Love a fresh salad with all the unusual green and purple, spicy and peppery flavors? Explore all the varieties, colors and textures of modern and heirloom lettuces.
How to Grow: Tomatoes - April 17 Wow! How do you pick your next favorite tomato variety? Let’s talk about favorites and new favorites. Learn how to have the first tomato on the block. Get a few plants to try and test.
All Classes are held at the Hardin County Extension Office beginning at 6:00 p.m. All Classes are $5 each. Classes are filled on a payment-received basis.
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