University of Vermont
Department of Plant and Soil Science
Fall News Article
GROWING GARLIC IS EASY
Dr. Leonard Perry, Horticulture Professor Emeritus
University of Vermont
Garlic is more than just a flavoring for foods, having many health
benefits. Studies have shown that garlic has antioxidant properties,
promoting the health of the heart and immune systems. “Allicin”-- the
chemical produced when garlic is chopped, chewed, or bruised-- is a powerful
antibiotic. Garlic even has been shown to reduce
cholesterol. Successful growing of garlic starts with choosing
the right "seeds", and giving the correct growing conditions and culture.
Garlic is related to onion, leeks and shallot, only it has a "bulb" composed
of individual wedges called "cloves". It is one of these cloves that
you plant in the fall, soon after the first frost (32 degrees F) but ideally
before the first hard frost (28 degrees F or below). This will give
time for roots to form before the ground gets too cold. Cloves are
planted in the fall, as it is the winter cold that is needed to form the
side buds the following year that will grow to make the new cloves that
you'll harvest next summer. Plants cloves about four inches apart and two
inches deep, the pointed side up.
There are three types of garlic varieties. The elephant or
great-headed garlic is related closely to leeks, a mild flavor between
garlic and onions. It has a large bulb and few cloves. More
common are the stiffneck or hardneck varieties, with cloves surrounding a
thick central stem that curls as it grows. These have a mild flavor,
are the most cold hardy, but don't store as well as the more common
varieties. Varieties include Rocambole, purple-striped, and porcelain
types. Rocambole types are popular as they adapt to changing weather,
and are easy to peel.
Most commonly seen are the softneck varieties, named from their stems or
"necks" staying soft when harvested. These are the ones you'll see
braided, and may be called Italian or common garlic. They
include the artichoke types you find in supermarkets, and the silverskins
with their very white outer skins and strong flavor.
There are dozens of varieties among these three main garlic types.
Buying locally adapted varieties, either from a local source or based on
reliable local recommendations, is the first key to success. Garlic
traditionally has been grown in hot climates, and you'll need varieties bred
for and adapted to cold climates for northern gardens. Bulbs from
grocery stores shouldn't be used as they may not be the right varieties, and
may have been treated to prevent sprouting.
Plant in well-drained weed-free soil, such as in low raised beds.
Slightly dry soils are best, with a pH of 6 to 7. Incorporate plenty of
compost in the fall, and you may not need to fertilize in spring. Or,
you may apply a general garden fertilizer along rows as shoots emerge in
spring, then again 3 weeks later. Don't fertilize after early May to
avoid delaying bulb formation.
Water deeply as needed, especially on sandy soils. Stop watering a
couple weeks before harvest. Garlic roots are near the surface so, if
cultivating for weeds, hoe shallowly and use care. Be careful to avoid
To avoid potential diseases, don't plant where other onion crops have been
grown during the past 2 or 3 years. Proper soil, mulching, and crop
rotation will lessen the chance of any diseases. Garlic has few, if
any, insect problems.
Large cloves produce the largest bulbs next year. Separate the cloves from
bulbs, keeping the papery husks on, and plant with tips pointing up.
Plant 2 inches deep, 4 to 6 inches apart in rows, with rows a foot apart.
You can plant small cloves closer, or in patches to harvest the tops as
garlic greens. Figure that a pound of cloves that you plant this fall may
yield 7 to 10 pounds of bulbs next summer.
Although you won't see growth until spring, roots will begin growing.
Mulch heavily to at least 6 inches deep, such as with weed-free straw, to
keep the soil warmer in fall and winter. Remove mulch in spring,
leaving some for weed suppression. Planting soon enough in fall, and
mulching deeply, will help prevent the cloves being heaved out of the ground
with spring frost.
Garlic is harvested in mid-summer, early to mid July in the north, but stage
of growth not the calendar is the indicator of when to harvest. You
should start checking the bulbs when the foliage begins to die off.
You need to check the bulbs, not just use the tops dying, as yearly climate
conditions can affect the tops and not the bulbs.
The bulbs are of course not solid like a flower bulb, but rather have the
cloves encased in several papery layers called "sheaths". Harvest too
soon, and the cloves won't be segmented yet. Harvest too late and the
sheaths will have come off, leaving just the cloves that are hard to get out
of the ground or they may even begin growing. Ideal harvest is when
there are 2 to 4 sheath layers present, which occurs over about a 2-week
Once harvested, wash the bulbs and allow them to dry for a week or so, out
of direct sun. Then trim off the roots, remove the outer dried sheath
layers, and then braid if you wish for storage. Cool (50 to 65 degrees
F), dry, and well-ventilated are ideal conditions for storage. Check
monthly to discard any soft bulbs that may be rotting internally. Set
aside the largest cloves for planting again in fall.
Return to Perry's Perennial