by Leonard Perry
by Leonard Perry


In extension I serve as an advisor and consultant to the greenhouse and nursery industry, primarily in Vermont but throughout the region and beyond as well.

I give presentations on my research to the industry, and to home groups. In Research, my focus is "herbaceous perennial production systems".

His website is at  Leonards zone of gardening: home with my trials, generally USDA 4a. Campus in Burlington is 5.

September 9, 2018

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 injuring plants.

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 period.

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.

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