Overwintering Onions & Garlic

Now is the time to get your onion and garlic sets.  Learn all about onions and garlic in this posting.

Garlic and onions can be planted in either the Spring or in the Fall.  I've done both and have settled on the Fall as my preferred time because there are fewer pest problems to deal with during the Winter months and over the winter the bulbs have an opportunity to create strong root systems.  Consequently, Fall plantings tend to produce larger bulbs.

For most gardeners, onions should be planted in September or October.  Garlic is generally planted a bit later -- October or November.  A good rule of thumb is to plant garlic sets after your first major frost of the year. 

Seeds or Bulbs?

Garlic is almost always grown from bulbs. Onions can be grown from either seeds or bulbs, but I plant bulbs because I find them so convenient. Onion and garlic bulbs (generally referred to as "sets") can be purchased from your local garden center, or from various mail order suppliers.  You'll find that onion and garlic sets sold at the garden center are less expensive, but you won't have much of a selection.  In fact, the onions sold at my local garden center are sold in bags that don't even list the variety, just "yellow onions" and "red onions." If you decide to order your sets from a mail order supplier, I recommend Territorial Seed company.  They have a particularly good selection of both onions and garlic.  Other potential suppliers include Dixondale Farms (sell onion sets) and Baker Creek (sell an interesting range of onions but as seeds only)

Culture

Plant onions and garlic in full sun and in loose, well drained soil. The drainage is particularly important since very wet soils will cause the bulbs to rot.

To plant garlic, first separate the bulb into individual cloves. Plant these six inches apart in all directions. Garlic should be planted two inches deep into the soil with the pointed end of the bulb facing the sky. 

Plant onions six inches apart in all directions.  The pointed part of the bulb should be facing upward towards the sky and the tip of the bulb should be just poking out of the soil. 

When selecting onion varieties, choose ones that are appropriate for your area.  Onions bulb in response to the number of hours of sunlight they receive.  In the North, the amount of daily sunshine varies dramatically during the course of the year, with many hours of sunshine in the Summer and relatively few during Winter.  In the deep South, day lengths are much more consistent during the course of the year and summer days are not as long as they are in the North.  So folks in the Southern U.S. should buy "short-day" varieties (bulbs start to form when there are 10-12 hours of sunshine) and folks in the Northern U.S. should buy "long-day" varieties (bulbs start to form when there are 14-16 hours of sunshine). Intermediate-day onions fall between these extremes (bulbs start to form at 12-14 hours of sunshine) .  See the below map of the U.S. to determine which type of onion is right for you or check out the  Gaisma web site which lists hours of sunshine by month for the U.S. and other countries.

Harvesting

Garlic and Onions planted in the Fall should be ready for harvest in June or July.  Timing really depends on variety and your location.  The best way to tell when to harvest is to observe for your plants for clues that it is time to harvest.

• Harvest onions when the leaves lose their color and fall over.  Once this occurs, leave the onions in the ground for another 10 days to allow the onions to reach full maturity.  If possible, harvest onions on a sunny day since the bulbs will contain less moisture and will store better.  After removing from the ground, cure in the sun for 1 day to kill the root system of the bulb.  This also improves the storage life of your onions.  Then store in a cool, dark and dry place. 
  
• Garlic is a little trickier.  Wait till most of the leaves die back and turn brown, but before all of the leaves have toppled over as with onions.  I recommend testing by harvesting a bulb or two and checking to see if they are mature.  The bulb should be the appropriate size for the variety you are growing and you should be able to feel the individual cloves under the outer skin of the bulb.  If so, harvest the garlic and then cure in a dry place for two to four weeks.  Longer for very large bulbs.  When storing garlic, I don't trim the leaves or the roots.  I believe this helps preserve them, but there are more opinions on the best way to cure garlic than there are stars in the sky.
  

Harvesting Garlic, from the Tacuinum Sanitatus, 1500's.

Onion and Garlic Varieties

There are many varieties of onions and garlic from which to choose.  The varieties differ in terms of their taste characteristics (strong/hot or mild), storage capabilities (short and long storage) and growth habit. (early, mid and late season for garlic or short-day and long-day for onions)

When choosing an onion for your garden, be careful to select one that will work in your location; onion plants create bulbs based on the number of hours of sunlight they receive and are sold as "long-day," "short-day," and "intermediate day" varieties.  Northern gardeners should purchase long-day onions and gardeners in the South should opt for short-day onions.   Onions also differ dramatically in terms of their size, from tiny "pearl" onions up to the huge Ailsa Craig that can tip the scales at up to 6 pounds.  Check out the varieties offered by mail order companies to find onions and garlic that meet your tastes and geographic requirements.  Here are some varieties you might consider:

• Purple Glazer Garlic - a mild tasting, easy to peel, mid-season variety.
• Music Garlic - a moderately hot, mid season variety with high yields.
• Chesnok Red Garlic - a strong, late season garlic that is good for cooking.
• Ontario Purple Trillium garlic - a very strong and very early maturing garlic.
• Borrettana Cipollini onion - a small (2 inch), flat, yellow, long-day onion that is a good storage.
• Red Wethersfield onion - a red, long-day onion thats shaped like a flattened globe.  It's an heirloom variety from Wethersfield, Connecticut.
• White Bermuda onion - a white short-day heirloom originally from Bermuda but now grow extensively in Texas.
• Candy - A large, intermediate-day hybrid onion.

To learn more about garlic, see my posting, Everything You Ever Wanted To Know About Garlic