How To Grow Garlic
Adapted from the Iowa State University Horticulture Guide:
Garlic (Allium sativum) is a member of the onion family (Alliaceae)
along with onions, chives, shallots, leeks, and elephant garlic.
Garlic is distinguished from other family members by its flat leaves
and clove-like bulbs. Each garlic bulb contains several small scales
or cloves enclosed in a white or purplish parchment-like sheath.
Garlic cultivars are classified as either hardneck or softneck.
Hardneck cultivars (Allium sativum var. ophioscorodon)
produce a flower stalk (technically a scape) and are often termed
“top-setting” or “bolting” cultivars. Flowers, if they are produced,
usually abort. Bulbils (small bulblets) are produced on top of the
scape. The flower stalks of some hardneck garlic are distinctly
coiled. These types are referred to as rocambole or serpent garlic.
Typically, hardneck garlic cultivars have 4 to 12 cloves surrounding
the flower stalk. Because of the hard flower stalk, they are
difficult to braid. Garlic Scapes are completely edible and
considered a delicacy. Watch our
recipes page for
delicious ways to prepare garlic scapes.
Softneck cultivars (Allium sativum var. sativum)
are sometimes referred to as “artichoke” cultivars and do not
produce a seed stalk. These cultivars are commonly used in
California for commercial production. However, some softneck
cultivars are suitable for cold climates. Softneck cultivars are
generally more productive than hardnecks because all the energy goes
to producing a bulb rather than a bulb and flower stalk. Bulbs have
10 to 40 cloves arranged in layers. Softneck garlic tends to have a
much longer shelf life than hardneck garlic and typically can be
stored for 6 to 8 months without significant deterioration. They
also are easy to braid.
Elephant, porcelain, or greathead garlic is actually a type of
leek (Allium ampeloprasum). Elephant garlic is much larger
than true garlic, often weighing as much as 1 pound per bulb. They
also store well. The taste of elephant garlic is much milder than
that of true garlic, but in cold climates it can develop a sharp or
Preparation of the Garlic Bulbs/Cloves
Open your garlic box the same day it is received! This will help
prevent mold/mildew/rot, as it will allow the garlic to continue
drying. Place the garlic in a cool location away from sunlight as
you wait for the proper planting time.
Up to 2 days prior to planting (but not longer), "shuck" the
garlic. Remove the outer husks and separate the cloves, leaving the
skins on the individual cloves. Store the
cloves in a cool location away from sunlight.
One helpful step to help avoid disease is to shuck your garlic away
from your field/garden, so the dirt particles and shucks can not
contaminate your soil. This may be an unnecessary precaution, but
it's an easy one to do. Therefore, we recommend shucking garlic away
from your field/garden.
Dipping/soaking cloves: more to come here in the near future...
Garlic grows best in well-drained, fertile soils that are high in
organic matter. Misshapen bulbs may result when garlic is grown in
heavy, clay soils. Incorporating compost or well-rotted manure into
heavy, clay soils can be beneficial. The optimum soil pH for garlic
is between 6 and 7. Before planting, soils should be well tilled to
provide a loose growing bed for bulb development. Because garlic
plants do not produce true seeds, garlic is grown by planting
cloves. Garlic cloves can be purchased at garden centers or from
mail-order companies, though direct purchase online from growers is
typically more economical.
Planting cloves from garlic purchased at the
grocery store is not recommended because these are usually softneck
cultivars that are mainly adapted to mild climates. Additionally,
most grocery store garlic has been exposed to chemicals that
postpone or prevent growth for longer shelf life.
Cloves should be planted in fall in most of the US (October to
early November) or early spring (late March to early April).
Spring-planted garlic will not likely achieve the same size as
fall-planted garlic. Contact
your local Extension Office or state Extension for information about
planting times specific to your area.
Fall-planted garlic should be mulched with a 4- to 6-inch layer
of weed-seed free straw to help prevent winter injury. In early
spring, move the straw to between the rows to allow the garlic
foliage to emerge and moisture to evaporate from the soil. The mulch
helps control weeds during the growing season.
Late spring planting results in smaller bulbs at harvest.
Plant cloves with the pointed side up, root end down. When planted upside down,
misshapen bulbs often develop. Plant cloves about 1 inch deep, or
contact your Extension Office for recommended depth for your
Hardneck (top-setting) garlic cultivars also may also be grown from the
bulbils or bulblets. Plant the bulblets in early spring and allow to
grow in the same area for 18 months. By the end of the first season,
the bulblets will form “rounds” or unsegmented bulbs. Left
undisturbed, they will form a cluster of cloves by the following
Place cloves 3 to 5 inches apart within the row. Rows should be
spaced 18 to 24 inches apart.
We suggest that you contact your local agricultural extension
office for recommendations specific to your growing area. A list of
offices, by county, can be found here:
Garlic requires more fertilizer than many vegetables. Incorporate
1 to 2 pounds of an all-purpose garden fertilizer (10-10-10) per 100
square feet before planting. One month after planting apply an
additional pound per 100 foot of row in a band 3 to 4 inches from
the base of the plants. Avoid nitrogen applications after the first
week of May because bulbing may be delayed. Soil tests should be
taken before planting to determine phosphorus and potassium needs.
If you prefer to garden naturally, try fertilizing with blood
meal, bone meal, and/or fish meal.
Water plants once per week during dry weather. Stop irrigating in
late June to allow the foliage to yellow and die before harvest.
Like an onion, garlic has a shallow root system. Weeds should be
removed carefully to avoid disturbing or pulling up the garlic bulbs
with the weeds. Mulches help control weeds and conserve soil
Most garlic diseases are either soil- or set-borne and usually
can be controlled with proper rotation and planting disease-free
sets. Before planting, check each clove for signs of disease.
Discard any infected cloves or bruised cloves because they may
decay in the soil. Many garlic cultivars are susceptible to yellow
The development of yellow tips early in the season (before bulbing) may drastically reduce yields. It is usually a sign of
water stress, nutrient deficiency, or disease. Insects are not a
major problem for garlic production, though a few destructive pests
Harvest and Storage
In late spring/early summer, the garlic begins to change from a
green onion-looking plant to forming bulbs. The greatest part of the
size develops in the last month before harvest.
Spring garlic looks similar to green onions. It has
not yet begun to form cloves in mid/late April in Iowa. Spring
garlic can be eaten, but of course won't allow you to produce as
large of a quantity as if it matures before harvest. Still, it is
another unique way to enjoy your garlic!
Carefully dig garlic bulbs when the foliage starts to turn yellow
and die, most often when half of the leaves are dying. Yellowing
normally occurs between June and September
(varying by climate/zone).
Dry or cure the bulbs in a warm, well-ventilated, and shaded
location for at least 2 to 3 weeks.
After drying, remove the foliage 1 inch
above the bulbs or use the foliage to braid the bulbs together.
Place the bulbs in a mesh bag or open crate and store where it is
cool (32–40°F) and dry (65–70% relative humidity). Softneck types
can be stored for 6 months or more, whereas hardneck types may only
store for approximately 3-5 months. More about how to store garlic
For more information
If you have any questions, feel free
to contact us!
Additional information also is available from these Web sites,
and also your state's Extension web site:
ISU Extension Publications