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Allium ascalonicum. Shallots, multiplier onions and potato onions are closely related members of the same family. As in any family, the individuals possess different qualities but are grown much the same.

When to plant:

It is always best to plant in the fall because fall-plantings yield twice as much. Protected by a good mulch and snow cover, these onions, have survived minus 25°F. However, if your winters are unusually severe, you might test-plant a few in fall the first time you grow them and save the rest to plant in spring. The exact time to plant must be learned by experience. What you want is for the bulbs to establish a strong root system, but not to make much, if any, tender top growth before the ground freezes. Normally, planting 4-6 weeks before hard winter comes is about right. The top growth may appear, make a few inches of growth and die back during winter, but if the bulb hasn’t had its food reserves sucked down too hard by making leaves in fall, it will still retain enough vigor to burst into rapid growth as soon as the soil warms up.

Soil preparation:

All members of the onion family grow best in light loam that is rich in organic matter and plant nutrients. Large bulbing onions are especially fussy in this regard and rarely do well when grown under less than ideal conditions. The smaller onions like shallots, multipliers and potato onions yield reasonably well under many conditions, just so long as the soil is well-fertilized, well-drained and kept moist. However, waterlogged soil will make the bulbs rot or adversely affect their appearance and quality. In infertile soil the bulbs will be very small. .

 Growing:

If you want really large bulbs, side dress the plants when growth resumes in spring. Organic gardeners can use chicken manure or any kind of seed-meal (cottonseed meal, canola meal, linseed, soybean, etc.) at a rate of about 1/2 to 1 gallon per 50 row feet. When the bulbing begins, any mulch or soil covering the bulbs should be pulled back so the bulbs form on the surface of the soil and dry down.

 Harvest:

The tops of these species often make very tasty scallions, especially potato onions. However, if you snip off too many sprouts, there will be fewer and smaller bulbs. It is important that the bulbs form tough protective skins. To accomplish this the plants must mature in dry soil. So as the bulbs are forming you should stop watering them. The time to harvest is when most of the tops have browned off and fallen over. Loosen the soil first with a spading fork and then gently lift the bulbs. Their skins have not hardened yet so it is important to avoid bruising or tearing the skin. The bulbs, with their tops still attached should be air-dried for 2-3 weeks until the tops have completely shriveled. Then cut the tops off with sharp scissors or pruning shears – about 1 inch above the bulb. Spread the bulbs out on wire racks in the shade or in a garage to cure for 2-3 months. By then it will be time to replant or store them for the winter (those you haven’t eaten yet).

Storage:

Like all onion bulbs, shallots, multiplier onions and potato onions need cool, dry storage with lots of air circulation. They are best hung in mesh sacks at a temperature of about 40°F., but they will keep quite well at 50°F if they have been properly cured and are not tightly packed.

 

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For soil testing or other questions specific to your growing climate, please contact your local county extension agent.

Visit http://www.almanac.com/content/cooperative-extension-services to find the office nearest you.