The SkeeterBytes Onion Page

WHAT ARE THE BEST VARIETIES FOR MY AREA?
To decide what variety is best for your area, you must first determine whether you are in a short day, intermediate day, or long day area. The further north you are, the longer number of daylight hours during the summer. Long-day onions generally do better in northern states, while intermediate-day onions do better in the middle section of the country and short-days are better suited for the south. When onions are first planted, their growth is concentrated on new roots and green leaves, or tops. The onion will first form a top then when a specific combination of daylight, darkness, and temperature is reached, bulb formation starts. The size of the mature onion bulb depends on the number and size of the tops. For each leaf there will be a ring of onion; the larger the leaf, the larger the ring will become. The confusing part is that every variety needs a particular combination. For instance, a variety that needs many hours of sunlight will not perform well in an area that receives fewer hours of light.

Soil Preparation
While waiting for your onion plants, you may want to begin soil preparation. Onions plants are best
grown on raised beds at least 4" high and 20" wide. Onions need a very fertile and well-balanced soil. Organic gardeners should work in rich finished compost, high in nitrogen and phosphorous with plentiful minerals. Spread lime if soil is too acidic. Prior to planting make a trench in the top of the bed 4" deep and distribute one-half cup of Dixondale Farms 10-20-10 per 10 linear feet of soil. Cover the fertilizer with 2 inches of soil.

HOW MANY ROWS WILL ONE BUNCH PLANT?
One bunch of onion plants (usually about 60 plants) will plant 10 ft. of double row, provided they are spaced 4 inches apart. If space is a problem, plant the onion plants 2 inches apart. In thirty days they will be large enough for green onions. Pull every other one as needed, thus leaving a 4-inch spacing for the onion growing to maturity.

Can I Grow a Short-Day Onion in the North or a Long-Day Onion in the South?

The quick answer is no. If you plant a variety of onion not intended for your area, it will still make an onion, but probably not as large as you would have if you planted the right variety for your area.

Let’s consider a short-day variety planted in the north. You probably would not be able to plant it until late March or early April. The short days of May and June will induce bulbing before a sufficient amount of foliage has developed. Without sufficient foliage, the carbohydrates necessary for optimum growth are not produced, resulting in small bulbs at harvest. However, if you can give the onion an extra push early in the season with extra fertilizer high in nitrogen, you will encourage leaf growth.

If you plant long-day varieties in the south, the onions will mature later in the summer. Additionally, in some areas of the Deep South there aren’t enough hours of daylight to initiate the bulbing process. Miami never gets 16 hours of daylight.

The challenge long-day onions face in the southern states is the intense heat they are exposed to during the last 2 months of maturity. This likely will cause difficult leaf formation and can make a lot of top and never produce a bulb because the tops die before bulb formation. But the plants can thrive if you keep them well watered. Use drip irrigation: the leaves need to be kept dry to discourage disease as well as scorching by the sun.

10 Ways to Ensure a Great Onion Crop

1. Plant the right variety at the right time of year for your area.
2. When your plants arrive remove them from the box and place them in a well-ventilated, cool area until you can plant.
3. Keep plants dry until you can plant. Do not put them in dirt or water.
4. Fertilize before planting and during the growing season.
5. Choose a location with good drainage and full sun.
6. Water thoroughly and immediately after planting.
7. Use drip or furrow irrigation rather than an overhead sprinkler system, which may promote the rapid spread of disease.
8. Keep the garden well weeded.
9. Keep the soil loose around the onions when they begin to bulb.
10. Harvest the onions when ready so they do not rot in the ground.

Which Variety is Best for Me?

The size of the onion bulb depends upon the number and size of green leaves, or tops. From each leaf a ring of onion develops; the larger the leaf, the larger the ring. The perfect onion has 13 rings.

The onion first forms a top and then, depending on the onion variety and length of daylight, starts to form the bulb from the lengthening leaf base. Onions are divided into three categories: long-day, intermediate-day, and short-day. Long-day onion varieties stop forming tops and begin to form bulbs when day length reaches 14 to 16 hours. Intermediate-day, or mid-day onion plants start making bulbs with 12 to 14 hours of daylight, while short-day onions start makings bulbs much earlier in the year, when there are only 10 to 12 hours of daylight.

The day length of any place in the United States is determined by latitude and time of year. At the equator the day length is almost always 12 hours. As the latitude increases toward the North Pole, the summer days become longer.

Cool weather at the start of the growing season encourages heavy leaf growth, and this helps produce larger bulbs. Leaf growth should start as early as possible in the winter (short-day) or spring (long-day). Long-day onions generally do better in northern states (north of the 37th parallel), while intermediate-day onions do better in the middle section of the country (35th to 37th parallel), and short-day plants do better in the south (south of the 35th parallel).

Actually, onions are sensitive to the dark period of the night rather than to the length of the day. Bulbing is not determined by day length alone but also by the interaction of day length, temperature, and light intensity. The rate of bulbing is more rapid with high light intensity and increased temperature. The optimum temperature for rapid bulb development is between 75(F and 85(F; bulb growth is poor below 50(F and above 87(F.

Why Not Grow Onions from Seed?

Seeds are harder to establish then transplants. The time between planting seed and harvesting is too short to make large bulbs in several areas of the country. Generally, a transplant with four or five leaves can be planted at the same time as seed, so you get a head start on making large bulbs. Seeds do offer more varieties; however, and they can be started in greenhouses to produce transplants.
What Is the Difference between an Onion Set and a Transplant?

An onion set is a small bulb, stored from the previous year's onion crop. A transplant is a plant between 10 and 20 weeks old that has not been through the bulbing process. An onion is a biannual, which means it has two lives. In its first life it grows from seed to set, and in its second life it produces a larger bulb. Sets are usually quite pungent and only good storage types can be kept for next year. A transplant is much less likely to bolt or go to seed than a set.
What Is the Difference between a White Onion and a Yellow Onion of the Same Variety?

Almost 70 percent of all onions are yellows, and there is a good reason for that. Yellow onions tend to be easier to grow than whites or reds. They generally have a tougher skin and heavier foliage. Whites are susceptible to greening (green streaks) if rained on close to harvest. They also are more susceptible to sunburning. It is difficult to make reds achieve the desired size. This is generally why reds and whites cost more in your supermarket.

What Is A Hybrid?
A hybrid is a cross between two different cultivars. Generally, a male sterile variety is bred from a fertile cultivar and produces the F1, which stands for "first-cross." Other varieties are "open-pollinated," which means their seed heads are not sterile and they can reproduce naturally. A hybrid can still send up a seed stalk, but the seed will not produce the same variety as the bulb.

The number of different varieties is almost endless, since each can be tailored to grow satisfactorily in most areas of the country. Varieties are developed for attractiveness, resistance to disease and insects, high yield, freedom from doubles and splits, resistance to bolt, storage ability, capability to produce seed, taste, pungency, and uniformity in size, color, shape and time of maturity. Obviously, not all of these characteristics can be found in a single variety. Therefore, many varieties have been developed to meet the needs of different regions.

How Are Onions Classified by Size?

A super colossal is 4 1/2 inches in diameter, colossal onion is 4 inches and up, a jumbo is 3 inches and up, a medium is 2 to 3 1/2 inches, prepack are 1 3/4 to 3 inches, small are 1 to 2 3/4 inches, and a boiler is 1 to 1 ? inches.
When Should I Plant?

Onions are very cold resistant and can survive temperatures as low as 20ºF. It is important to set out transplants as soon as possible, but a general rule of thumb is to set them out 4 to 6 weeks before the last average frost date. You can obtain this information from your Cooperative Extension Service.


How Should I Prepare My Beds?

Onions grow best on raised beds at least 4 inches high and 20 inches wide. They are also happiest in loose, fertile, well-drained soil with plenty of organic matter. Soil with a pH between 6.2 and 6.8 is most desirable, but don't worry if your pH is higher or lower. You can add sulphur to soil to lower pH and lime to raise it.

What Fertilizer Should I Use before Planting?

Onions require a good supply of nitrogen (N), high levels of phosphorus (P), and medium levels of potassium (K). The best time to provide these essential nutrients as well as other less essential nutrients such as copper, boron, manganese, magnesium, zinc, and iron is prior to planting so that the nutrients will be readily available at the root zone. Make a trench along the top of the bed 4 inches deep, distribute 1/2 cup of 10-20-10 fertilizer blended with the other micro-nutrients per 10 linear feet of row, cover the fertilizer with 2 inches of soil, and plant onions within 6 inches of the trench.

Organic farmers need to use an organic fertilizer made up of balanced proportions of ocean kelp and concentrated fish emulsion. Kelp is especially high in micro-nutrients and fish emulsion is a highly concentrated source of nitrogen.

Does the Size of the Transplant Affect Bulb Size?

The size of the transplant affects not only the bulb size but also the maturity date as well. That is one of the reasons all the tops don't fall down at the same time. The ideal plant is slightly smaller around than a pencil. Plants that are much larger (1 inch) have more of a tendency to bolt.

It is important that transplants be uniform in size, but this is often difficult because it requires uniform seeding, fertilization, irrigation, and temperatures - which are often not uniform or predictable every year.

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