A garlic bulb is the underground part of the garlic plant that you buy at the grocery store: a compact, papery-skinned bundle of individual segments called cloves. It’s technically a modified stem surrounded by fleshy storage leaves, making it a true bulb in the botanical sense, much like an onion or a tulip. Each bulb typically contains 8 to 14 cloves, though the exact number depends on the variety.
Anatomy of a Garlic Bulb
Three main structures make up a garlic bulb. The outermost layer is the tunic, a dry, papery sheath formed from older leaves that protects the cloves inside. Beneath the tunic sit the individual cloves, each wrapped in its own thinner protective skin that can range from white to purple or reddish depending on variety. At the very bottom is the basal plate, a small, flat disc of hardened stem tissue where the roots emerge.
Each clove is essentially a miniature bulb on its own. Inside its protective wrapper is a single fleshy storage leaf packed with nutrients and moisture. At the base of each clove, just above the basal plate, sits a tiny growing point surrounded by leaf buds. This is what sprouts into a new plant when you put a clove in the ground.
Hardneck vs. Softneck Varieties
Garlic falls into two broad categories, and knowing the difference helps you pick the right bulb for your kitchen.
Hardneck garlic grows a stiff central stalk and produces fewer, larger cloves arranged in a single ring around that stalk. It thrives in colder climates and tends to have bolder, more complex flavor. Hardneck types also send up curly green flower stalks called scapes in spring, which are edible and taste like mild garlic. Popular hardneck varieties include Siberian and German Extra Hardy.
Softneck garlic is what you’ll most often find at the supermarket. It has a flexible stem (perfect for braiding), more cloves per bulb layered in multiple rings, and a milder, more versatile flavor. Softneck varieties like California Early White and Inchelium Red store longer and grow better in warmer climates. They don’t normally produce scapes, though unusual growing conditions can occasionally trigger one.
What Gives Garlic Its Smell and Flavor
Whole, undamaged garlic cloves have almost no aroma. The characteristic smell and sharp taste only appear when you cut, crush, or chew the tissue. That’s because the flavor compound isn’t sitting in the clove ready-made. Instead, the clove stores a sulfur-containing amino acid and keeps it separated from a specific enzyme. When the cell walls break, the two mix, and within seconds a chain reaction produces allicin, the molecule responsible for garlic’s pungent kick. The finer you mince or press a clove, the more cells you rupture and the stronger the flavor becomes.
How a Garlic Bulb Grows
Garlic is planted as individual cloves, usually in late fall. Each clove sends out roots and a small shoot before going dormant for winter. Growth picks back up in spring, and bulbing, when the clove expands into a full multi-cloved bulb, happens in midsummer. The whole cycle from planting to harvest takes about eight to nine months. Fall-planted cloves produce significantly larger bulbs than spring-planted ones because they get a head start on root development.
When the lower leaves of the plant begin to yellow, the bulbs are ready to pull. Hardneck varieties also produce small bulbils at the top of their flower stalks. You can plant these too, but they take two full years to develop into a proper bulb.
Curing and Storing Garlic
Freshly harvested garlic needs to be cured before storage. Curing simply means drying the bulbs in a well-ventilated space out of direct sunlight for 10 to 14 days. You’ll know it’s done when the outer skins feel dry and crispy, the neck has tightened, and the cut stem center is hard. Good airflow is critical, and temperatures above 120°F can cause a condition called waxy breakdown that ruins the cloves.
Once cured, whole garlic bulbs store best at 56 to 58°F with 45 to 50% relative humidity. Dropping below 50°F actually encourages sprouting, which is the opposite of what most people expect. A cool pantry or basement works well. At room temperature, a whole unbroken bulb will last several weeks to a couple of months. Once you break the bulb open, individual cloves dry out faster, so use them within a week or two.
Picking a Good Bulb
A fresh garlic bulb feels firm and heavy for its size when you squeeze it gently. The tunic should be tight and papery, not loose or flaking apart. Soft spots mean the cloves inside are deteriorating. Dark patches or discoloration on the skin signal rot. If you peel a clove and it looks more yellow than white, it’s past its prime. Small green sprouts poking out of the top aren’t dangerous, but they indicate the garlic is aging and the flavor will be sharper and sometimes bitter.
Nutrition and Health Effects
Garlic is nutrient-dense relative to how little you use. A 100-gram serving of raw garlic (roughly three full bulbs, far more than most people eat at once) provides about 1.2 mg of vitamin B6 and 11 mg of vitamin C. In typical cooking quantities of a few cloves, garlic contributes trace amounts of these nutrients along with small doses of manganese and selenium.
Where garlic gets more interesting is its effect on blood pressure. A meta-analysis of 12 trials involving 553 people with high blood pressure found that garlic supplements lowered systolic blood pressure by about 8 to 10 points and diastolic pressure by 5 to 6 points, effects comparable to standard blood pressure medication. A separate review of 39 trials with 2,300 participants showed garlic improved total cholesterol and LDL cholesterol in people with mildly elevated levels. These studies used concentrated garlic supplements rather than fresh cloves, so the doses were higher than what you’d get from cooking alone, but regular culinary use still contributes.