How to Grow Alliums

What Varieties of Onion to Plant

Your choice of allium
variety will be determined by climate and by whether you
prefer seeds, transplants or sets.

For example, you should always check a cultivar’s day-length
requirement. Long-day varieties need the 13 to 16 hours of
daylight of Northern summers to mature. Short-day types
(such as Bermuda and Sweet Spanish) thrive in milder
climates with only 12 hours of daylight.

Seeds provide the greatest choice, but onions
grown from seed often take five months to mature, and the
plants they produce can be susceptible to diseases.
Transplants, sold in bunches, are seedlings
started in the current growing season. They usually form
good bulbs. Sets, immature bulbs from the previous year,
are the easiest to plant, the earliest to harvest and the
least susceptible to diseases. Unfortunately, only a few
varieties are available in this form, and not all will
yield good bulbs. (Look for small-bulbed sets, as large
ones may go to seed before producing a good-sized onion.)
For the Middle or Northern sections of the country, try
sets of Ebenezer (early yellow) and Stuttgarter (yellow,
nonsprouting).

In the South, pick a firm, sweet, mild Granex type. (The
famous Sweet Vidalia, grown in two Georgia counties, is yet
another Granex. The Walla Walla Sweet is equally prized in
the West.) Sweet Spanish types, such as Fiesta, generally
taste better than yellows and store fairly well. Bermudas
are slicing favorites but aren’t good keepers. Good white
storage onions include White Ebenezer in the North and
Granex White in the South. Red onions are normally very
pungent-and, as a general rule, the stronger-flavored
onions keep best of all. When planting bunching onions, you
can’t go wrong with the crisp flesh and mild flavor of
White Lisbon. Its dark green foliage is resistant to heat
and cold, and it stays fresh long after being pulled. Once
planted, winterhardy He-Shi-Ko-a perennial with white,
pungent flesh–will add flavor to meals for years,
while Wonder of Pompeii’s small, round, early bulbs are
great for pickling.

When to Plant Onions

The onion bed should be moist but well drained with a pH of
6 to 7. Sandy loam is ideal, but onions thrive in most any
soil if large quantities of well-aged manure, wood ashes
and bone meal in a 5:1:1 ratio are worked in to a depth of
six inches. This vegetable likes cool weather (55 degrees Fahrenheit to
75 degrees Fahrenheit) in its early stages. Therefore, plant seeds in
the spring in the North and (depending on the variety) in
the fall or winter in the South. Generally speaking,
frost-hardy onions can be sown four to six weeks before the
last frost date–or even earlier indoors or in a cold
frame. (Mix in some quick-sprouting radish seeds to mark
the onion bed and to lure any root maggots that might be
lurking in the soil away from your allium crop.) Sow the
seeds thickly about one-half inch deep.

Thin young sprouts to one inch apart. (When they’re started
under glass, transplant to the garden when two to three
inches tall.) Thin again a month later to two or three
inches apart, enjoying the tender rejects in salads and
other dishes. At the same time, dig the soil back to expose
the tops and sides of the bulbs to help stimulate bulb
formation. Position plants or sets two inches deep and four
to six inches apart, depending on whether you plan to
harvest some as scallions. If planting in rows instead of
raised beds, make the rows about two and a half feet apart.
Keep well weeded, but–because onions have shallow
roots–cut, don’t pull, any wild intruders. Once the
soil has warmed up, add a thick layer of mulch around and
between the onions to discourage weeds and to hold moisture
in the soil. (Transplants require more water than do sets.)

What Onion Problems and Pests to Watch For

Onions are mostly disease- and insect-resistant, but keep an
eye out for root maggots (small, white larvae that usually
enter the base of the bulbs and burrow upwards to feed on
the stems) and onion thrips (barely visible larvae that
cause bleached, deformed plants with silvery blotches).
There are, however, preventive measures that can be used to
deter both pests. Root maggots; for example, travel in a
line from one bulb to the next, so their threat will be
reduced if you scatter-plant onions throughout the garden.
(Keep in mind that alliums are good companion plants to
roses, lettuce, carrots, beets, parsnips and members of the
cabbage family, repelling such pests as aphids, Japanese
beetles and carrot flies.) As mentioned, maggots can also
be lured to radishes, which can be pulled up and destroyed
if infested. Also add a thin layer of wood ashes or sand
around the bulbs to discourage adult flies from laying
their eggs at the base of the plants.

Use rotenone if all else fails. Thrips overwinter in weeds,
so keep your onion patch clean. If that doesn’t work, try
an oil-and-water or tobacco spray, rotenone or pyrethrum. A
cheesecloth cover placed over your crop during May and June
will protect it from the lesser bulb fly, which enters
through the top of the onion bulb. Garlic-and-water sprays
also discourage this pest, along with the garden
springtail, a tiny purple insect with yellow spots. Onion
ailments are confined to smut (black leaves and pustule
patches between bulbs), downy mildew (a purplish mold) and
selfdescriptive pink root and neck rot–all of which
are caused by fungi in the soil. Avoid these infections by
practicing crop rotation, providing good drainage and
working a lot of humus into the onion bed.

How to Harvest and Store Onions

When onion tops turn
yellow, bend them over horizontally with the back of a rake
to stop the sap from flowing and divert growing energy into
the maturing bulb. Once the tops turn brown, wait for a
sunny period to pull or dig the crop, and dry the bulbs on
the ground for a few days. (To prevent sunscald, “shingle”
the onions by letting the tops of one row cover the bulbs
of another.) When the outer skins are thoroughly dry, wipe
off the dirt and dried roots, remove the tops (unless you
plan to braid them), and store your harvest in a cool, dry,
flat place. Hang braided onions or those kept in mesh bags
in an airy spot.

With the exception of green onions, which won’t keep long
even when refrigerated, mature bulbs can last indefinitely.
Therefore, onions aren’t usually canned or frozen. Pickled
onions, however, are a delightful treat. Just cover 10
pounds of small bulbs with boiling water and let them stand
for 2 minutes, drain, dip into cold water, drain again, and
peel. Soak overnight in lightly salted water. Then combine
3 cups of white vinegar, 3 cups of water, 1-1/2 cups of
sugar, 2 cloves of garlic, 2 bay leaves, 2 cinnamon sticks
and 5 whole cloves in a large pot and bring the mixture to
a boil. Add the drained onions and bring to a boil again.
Pack into sterilized jars and cover with the boiling
liquid, leaving 1/4 inch headspace. Adjust lids and process
in a boiling-water bath for 10 minutes. Makes 10 pints.

How to Grow Garlic (Allium sativum)

This perennial is highly adaptable to most parts of the
country, has similar soil requirements to those of onions
and likes cool temperatures during its early growth. It
also needs plenty of sun. If you want to grow garlic from
seed, California White is popular; Giant Cajun Garlic
offers extra-large, mild bulbs; Mexican Garlic is pungent
and hardy; and elephant garlic-Allium
scorodoprasum–produces one-pound, milder than-average
bulbs. Most people, however, use the cloves of store-bought
white garlic bulbs. These can be planted about eight weeks
before the last frost or in the fall if mulched heavily
where winters are severe.

Separate each segment gently (the larger cloves usually
produce the largest bulbs) and place them, plump side down,
one to two inches deep and four to six inches apart. Rows
should be at least one foot apart, but you’ll probably want
to scatter garlic throughout the garden for its insect
repelling properties. Don’t, however, plant it near your
peas or beans, as legumes don’t care for garlic companions.
Once in the ground, garlic will care for itself if you keep
weeds down and don’t let the soil dry out.

To produce larger bulbs, remove the flowers that appear on
the leaf stalks. Watch for signs of onion thrips, root
maggots and downy mildew, though such problems are unusual.
When garlic tops are about one foot tall, stop watering.
Once the tops begin to droop, knock down the foliage to
speed up the curing process and–a few days
later–loosen the soil and pull out the entire plant.
Dry in a cool location with low humidity to keep the bulbs
from molding. Remove the tops and store like onions. The
bulbs will last for several months–or up to a year if
wrapped and refrigerated. Use generously in recipes, for
garlic contains vitamins C and B, phosphorus, calcium and
potassium, as well as allicin, a chemical with antibiotic
properties that can minimize the effects of colds, aid the
digestive tract, ward off traveler’s dysentery, help
control high blood pressure and reduce the risk of heart
attacks and arteriosclerosis. Garlic sprays repel insects
and can deter dis eases such as downy mildew, cucumber and
bean rust, bean anthracnose and early tomato blight.

How to Grow Shallots (Allium ascalonicum)

It’s surprising that grocery-store shallots are so
expensive, because the plants are very easy to grow.
Extremely adaptable to practically any soil or climate,
this allium is beautiful, with its graceful, bright
blue-green stem, and its gray, angular, mild-flavored bulb
(related to the multiplying onion) is a favorite of French
chefs. (A young scallion is eaten whole, while the mature
bulb is used like a milder, superior-flavored garlic.) As
with garlic, it’s best to make your shallot sets by
dividing bulb clusters purchased from a store’s produce
section. (The only true shallot seeds available are the
Louisiana variety.) Each shallot will multiply and produce
four to eight new bulbs.

Shallots aren’t particular about soil, disliking only very
acid spots, but the earth must be well dug, because the
plants send feeder roots down to a depth of eight inches.
However, they have no lateral roots, so the cloves can be
planted close together. Plant them about one inch deep
(barely cover the tip of the clove) and two to three inches
apart in February or March. Light feeders, shallots like a
little phosphorus but don’t require rich soil. They can
also survive dry spells, but–for the best
growth–keep the soil weed-free and slightly moist.
Around June, draw the soil away from the bulbs. Though
growth stops with freezing temperatures, shallots are very
hardy and also will tolerate both low and intense light
conditions, flourishing best when temperatures are in the
mid-70s and daylight hours are long. Shallots can be
harvested as green onions at any time, and if the tops are
cut off near the soil, they’ll produce new ones.

In fact, cutting the tops and using them as you would
chives will promote bulb production. Bulbs mature in about
five months. At that time, pull them up, cut off the tops,
dry, and store them in a cool place–saving the
healthiest looking bulbs for next year’s crop.

How to Grow Chives (Allium schoenoprasum)

The early-spring, grass like chive has been enjoyed for
centuries in Britain and Europe and for thousands of years
in China. Though fairly tolerant of most soils and
locations, it rewards the gardener who gives it a
humusrich, moisture-holding home with superior flavor and
succulence. (Poor soil can even cause chive tips to
yellow.) The germination of spring-sown seeds will be slow,
and the first year is likely to be unproductive. Impatient
gardeners should set out chive clumps, which will be ready
to harvest two months later. Each clump should contain
about six bulbs, and the clusters should be spaced eight
inches apart. Every third year, dig up, divide, and replant
in another section of the garden. Chives are not evergreen
and will die back, so–before the first
frost–put a few clumps in pots, cut back the leaves
to about two inches, and bring them indoors for use in
winter dishes. Whether indoors or out, constant cutting is
necessary to keep up an ongoing supply of leaves. Flowers,
though attractive, also should be cut off.

How to Grow Leeks (Allium porrum)

Switzerland, Algeria and the Eastern Mediterranean all
claim to be the original home of the leek–and,
indeed, any place would be proud to claim this wonderful
allium. It’s very easy to grow, is resistant to pests and
diseases and can be harvested fresh from many gardens
throughout the winter so make sure to plant a large crop,
because this is the sweetest and most delicate-flavored of
all the onions. Though not very popular in this country,
leeks have been prized in ancient civilizations for three
or four thousand years.

Leeks thrive in temperate climates (growth will slow above
90 degrees Fahrenheit) and will withstand temperatures several degrees
below freezing. Though they prefer crumbly, rich loam, such
as woodland humus, they will do well in most soils if
well-rotted manure or good compost is worked in deeply.
However, they require a lot of moisture and dislike weeds.

Depending on the variety, leeks take from 70 to 110 days to
mature but can be harvested as green onions some three
weeks earlier. Their flavor is best, however, after the
first frost. To get a head start, sow seeds indoors in
flats two to three months before setting them out. At three
inches, thin the seedlings to one inch apart; when five
inches tall, thin to two inches apart. At about eight
inches, transplant to the garden, placing seedlings in
six-inch deep holes spaced six inches apart, and fill the
hole with water to anchor the roots. When the plants are
pencil size, carefully bank up the soil around the lower two
or three inches to blanch the leek, to improve both its
appearance and its delicate flavor.

And how you’ll love that flavor! Where temperatures seldom
fall below 10 degrees Fahrenheit, just pull leeks from the garden
throughout the winter. In colder climates, ball them up and
keep them in a box in a cool, dry place. Use them in any
recipe that will be enhanced by a delicate onion
flavor. (The long, white stem is most commonly eaten, though
the sharper tasting green tops are good, too.) Serve them
in wilted-spinach salad. (Saute chopped leeks and garlic in
a little bacon grease, stir in spinach leaves until wilted,
and serve topped with crumbled bacon.) If young and tender,
leeks can be creamed and used as an excellent topping for
toast. (Saute in butter, simmer, and add a cream sauce.)

Leek and Potato Soup Recipe

4 medium potatoes, peeled and diced
2 cups cold water
4 large leeks, sliced, including some fine-sliced green tops
1 large onion, chopped
2 tablespoons margarine or vegetable oil
3 cups milk
Dash of cayenne pepper
Salt and pepper to taste
2 tablespoons fresh minced parsley
1 cup cream

Cook potatoes in water about 10 minutes.
Saute leeks and onion in oil until golden.
Add to potatoes and stir in milk and seasonings.

Simmer until the flavors are blended (about 15 minutes).
Add parsley and heat almost to boiling, stirring frequently.
Enrich soup with cream and serve hot.