Garlic (Allium sativum) is an edible bulb plant that's closely related to the onion (Allium cepa). Hardneck garlic (Allium sativum var. ophioscorodon) is the variety that's typically grown in cooler climates. Its stalk, or neck, grows upward from the bulb and becomes rigid as it matures—hence its common name. Hardnecks also tend to form fewer but larger cloves than the softneck varieties. Garlic is typically planted in the fall, and it has a slow growth rate. Be mindful about where you plant it, as it has some compounds that are toxic to animals as well as to humans.
|Common Name||Hardneck garlic|
|Botanical Name||Allium sativum var. ophioscorodon|
|Plant Type||Vegetable, perennial, annual|
|Size||12–18 in. tall, 9-12 in. wide|
|Sun Exposure||Full sun|
|Soil Type||Loamy, well-drained|
|Soil pH||Acidic, neutral|
|Bloom Time||Spring, summer|
|Hardiness Zones||4–9 (USDA)|
|Toxicity||Toxic to people, toxic to pets|
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How to Plant Hardneck Garlic
When to Plant
Plant your garlic approximately six to eight weeks prior to your area’s projected first fall frost date. It’s important to give the bulbs enough time to establish roots before the ground freezes. The garlic will then go dormant over the winter until spring warmth promotes foliage (and bulb) growth.
It is possible to plant in the late winter or early spring in mild climates. However, the bulbs likely won’t grow as large due to the shortened growing season.
Selecting a Planting Site
Pick a sunny spot with loose soil for your garlic. Container growth is also an option if you don’t have a suitable garden site. Try to avoid a spot where other Allium species have been in the past few years, as pests and diseases that target the species can linger in the soil.
Spacing, Depth, and Support
Cloves should be planted 4 to 8 inches apart. Place them 2 inches deep in the soil with the pointed end up and wider end down. Rows should be 6 to 12 inches apart. A support structure shouldn't be necessary.
Hardneck Garlic Plant Care
Garlic requires full sun for optimal growth. That means at least six hours of direct sunlight on most days. However, if you live in a hot climate, garlic can struggle in the harsh afternoon sun, so give it a bit of shade.
Garlic grows best in a fertile loam or silty loam soil. The soil must be well-draining to prevent rot. A slightly acidic to neutral soil pH is ideal.
Water regularly to keep the soil moist but never soggy. Roughly an inch of water per week should suffice. However, it’s best to cut back on watering a few weeks before the bulb is fully mature to minimize the chances of it rotting.
Temperature and Humidity
Hardneck garlic tolerates cold well and actually needs a four- to eight-week dormancy period with temperatures below roughly 40 degrees Fahrenheit. Mild temperatures produce the best growth, and unseasonably high heat can stall growth. Humidity typically isn’t a factor as long as soil moisture needs are met and there’s good air circulation around the plants.
Garlic is a heavy-feeding plant. Add compost to the soil at the time of planting, and then apply an organic high-nitrogen fertilizer in the early spring. For the amount to use, follow the product label instructions. Fertilize again in early May right before the bulbs swell.
Most growers cut off the flower stalks to keep the plant's energy focused on bulb growth. But if you leave the flowers, bees and other insects will help to pollinate them.
Types of Hardneck Garlic
There are many types of hardneck garlic, including:
- ‘Spanish Roja’: This cultivar produces very large bulbs with a strong flavor.
- ‘Siberian’: This is a mild variety that has approximately five to nine cloves per bulb.
- 'Chesnok Red': This variety is known for its excellent taste that has an onion-like quality.
Hardneck vs. Softneck Garlic
Hardneck and softneck garlic are varieties of the same species. However, there are some key differences. While hardneck garlic has a rigid central stalk, softneck stalks remain more flexible. Softneck garlic also tends to have more thin, papery skin as opposed to hardneck’s thicker, but more brittle skin.
Harvesting Hardneck Garlic
Garlic planted in the fall will generally be ready to harvest anytime from late June to August. Foliage that’s yellowing and toppling over is a good indicator that the garlic bulbs are mature. Using a garden fork, dig up just one bulb first to check. If the head is divided into cloves and the skin is thick, brittle, and papery, it’s ready to harvest.
Gently lift the plants with your garden fork, keeping the roots and leaves intact. Brush off loose soil. Then, let the garlic cure in a shaded, dry spot with good air circulation for roughly two weeks. Hanging the garlic in mesh bags is helpful to let air flow all around it.
Once the skin has dried out, cut the roots to about 1/4 inch from the bulb and the leaves to about 1 inch from the bulb. The garlic is ready for eating now. You also can store bulbs longterm in a dark, cool, dry spot where they will keep for several months.
How to Grow Hardneck Garlic in Pots
Growing garlic in a container will allow you to closely control its light and soil conditions. The pot should be at least 10 to 12 inches wide and deep; cramped garlic will produce smaller bulbs. Make sure the pot has sufficient drainage holes. And pick a material, such as plastic, that won’t crack in cold temperatures, as the pot will be outside over winter.
Garlic plants generally send up flower stalks in the late spring to early summer. Promptly cut off these stalks. Leaving them on can divert the plant’s energy and consequently decrease bulb size.
Propagating Hardneck Garlic
Garlic plants usually don’t produce true seeds and are typically propagated by their cloves. If you have a bulb from a particular variety you like—or just an overabundant harvest—you can put it to use by creating new garlic plants. Plan to save one season’s harvest for growing the next season, typically planting in the fall. Here’s how:
- Select a healthy bulb that’s been stored. Make sure it has no softness, dark spots, or other signs of rot.
- Break the cloves apart, aiming to keep their wrappers intact.
- Plant them pointed side up, about 2 inches deep, and water to moisten the soil.
Potting and Repotting Hardneck Garlic
Use a loose organic vegetable potting mix when growing garlic in a container. You can mix some compost into the soil to improve its nutrient content and drainage. It's best to fill a container that will accommodate the garlic's mature size, rather than having to repot and disturb the bulb and its roots.
If the ground freezes in your climate over the winter, add a thick layer of mulch over your garlic to protect the bulbs from the cold. Remove the mulch in the spring once the danger of frost has passed.
Common Pests and Plant Diseases
Garlic has fairly good pest and disease resistance. But it can still be susceptible to the same problems that plague other Allium species.
Some common pests include onion maggots and onion thrips. Row covers can help to deter insects before they become a problem. Plus, white rot is a common fungal disease. Destroying affected plants and practicing good crop rotation is often the most effective way of dealing with fungal issues.
Is hardneck garlic easy to grow?
Garlic is a fairly easy crop to grow as long as you are patient throughout its long growing season. It's also essential to make sure it's never in waterlogged soil.
How long does it take to grow hardneck garlic?
Garlic will be ready to harvest approximately eight to nine months after planting. This can differ by variety, so be sure to check your plant label.
Does hardneck garlic come back every year?
Garlic is technically a perennial with bulbs continuing to form new plants when left in the ground. However, most gardeners grow it as an annual to harvest the bulbs.