Garlic is a staple crop in the Northeast, but it can be difficult to know exactly when to plant and harvest garlic in this region. There are quite a few important guidelines during all stages of garlic cultivation. In Connecticut, planting should take place in early- to late-November. The goal is to time planting for the development of roots, but not enough time for the shoots to emerge from soil before winter. Aim for a garlic harvest of mid- to late-July the following year. There are two types of garlic, hardneck and softneck, but the hardneck type is more commonly grown in New England due to their flavor and appearance, so we will only be referring to that type in this article. Curing and storage are also crucial to a productive garlic harvest. This article will detail the necessary steps to ensuring a lovely and bountiful garlic harvest! 

Planting and seed garlic

First things first, we will discuss when and how to plant garlic. Starting with clean seed is critical—you want to use the best seed to set yourself up for success from the beginning. When selecting seed cloves to store for the next planting, look for the cream of the crop. Cloves selected for seed should be of the highest quality, larger in size, and disease-free. Disease can easily spread throughout a field if using infected seed cloves. Carefully separate cloves after removing the papery outer skin. Make sure to store seed garlic at 50°F, with a relative humidity of 65-70%. 

In this region and climate, garlic planting is done in the fall, as garlic requires a period of winter chilling to initiate formation of the bulb. However, planting too early may cause the seed to produce shoots before winter and expose the plant to cold damage. Aiming for a planting 4 to 6 weeks before first hard frost is recommended for Connecticut growers to allow garlic the 9-month growing window it needs before harvest. This typically shakes out to early- to late-November, but can shift slightly year to year, so keeping an eye on the forecast remains important.

Planting seed into well-drained soil and at proper spacing is vital for bulb development. A simple way to establish a well-drained planting area is to create raised beds. Seed cloves should then be planted 3 to 6 inches apart in-row 2 to 3 inches deep, with their points facing upwards. Spacing between rows should allow for preferred methods of weed control, irrigation, and/or mulching. The planted area should then be covered with at least 3 inches of mulch—many growers prefer to use a straw mulch—to keep the ground insulated throughout the winter. This mulch then acts as weed control into the spring, and can help to regulate soil moisture as well. 

Harvest

Once spring rolls around, your garlic will be growing tall and green up through its cozy winter bed. As the season progresses, the scape, or a false flower stalk, will emerge. This typically happens during June. Many growers prefer to harvest the garlic scapes, while others choose to leave them intact. Harvesting the scapes has been thought to allow the plants to focus energy on bulb formation and development. Scapes can also be marketed and sold as a specialty agricultural product. They should be cut after they curl. Only hardneck garlic produces a scape. 

Another garlic product is green garlic. This is premature garlic that is harvested before the cloves start to become defined within the head. It is used in a similar way to scallions or green onion, and is ready when the plant has begun to fall over, but 50% of the leaves are still green. This indicates that the bulbs are still intact.

Hardneck garlic should be harvested when the bulbs are fully mature. But how do you know when exactly that is? There are a few tips and tricks to help answer this question. First is to check the leaves of your garlic plants. If the bottom 3 leaves are brown and senesced, you have about a 2-week window within which to complete your harvest. After these 2 weeks are up, the bulbs will not cure or store properly, as the outer skin will disintegrate. Refer to photo 4 for a visual on the appropriate harvest stage.

Another trick is to dig up 1 or 2 plants to check the development of the bulb. Under-dig the entire plant, making sure not to damage or cut the bulb with your tool, and cut the head lengthwise. Refer to photo 5 for a comparison of an underdeveloped versus fully developed head of garlic. If the cloves within the bulb are not differentiated, the crop is not ready for harvest and needs more time in the ground. The cloves being separated within the wrapper is an indicator that the rest of the crop is ready. 

One last indicator of readiness is the shape of the clove in the bulb. Each individual clove should be tightly wrapped within the head, and have developed from a round to wedge shape. In hardneck varieties, the cloves may actually begin to pull away from the stalk when they’re fully developed. 

When you’re confident the garlic is ready for harvest, begin by undercutting or under-digging your plants carefully. Gently pull each plant and shake or wipe off the dirt—do not kick or hit the heads against anything, as wounding the bulbs can result in poor storage quality. Harvest ideally takes place on a sunny, dry day earlier in the morning (before 11 am) to avoid sun scalding. 

Curing and storage 

The post-harvest curing and storage of garlic is critical in making marketable, long-lasting bulbs. Curing areas should be kept dry (do not wash), with minimal moisture brought in from harvested plants—this means removing as much soil as possible before bringing the crop indoors. Maintain low relative humidity (about 50%) wherever you’re planning to cure the bulbs. Hang garlic in a well-ventilated area where sunscald will not be an issue. Avoid temperatures at or above 90°F. The curing process takes anywhere from 10 days to 4 weeks. Bulbs are properly cured once the outer skin is dry and crispy and the center of the stem is hard. Garlic stems can be cut to ~1 inch length at any point after curing has completed.  

Store garlic for consumption in a location where a temperature of 32-35°F can be maintained, with a relative humidity of 65-70%. Garlic that has been selected for seed can be stored at 50°F, with a relative humidity of 65-70%.   

Pests and diseases

There are a handful of pests that affect garlic, including onion thrips, onion maggots, mites, and nematodes. Diseases that affect garlic include botrytis, basal rot, white rot, and downy mildew. For more detailed information on symptoms and pest management, please refer to this factsheet from Cornell Extension. Remember to follow the label when using any pesticide!

References

(2013, January). Garlic Harvest, Curing, and Storage. UMass Extension Vegetable Program. Retrieved October 24, 2023, from https://ag.umass.edu/vegetable/fact-sheets/garlic-harvest-curing-storage 

(2013, January). Garlic. UMass Extension Vegetable Program. Retrieved October 24, 2023, from https://ag.umass.edu/vegetable/fact-sheets/garlic 

Frederick, P., Leviant, E., & Hlubik, W. (2014, June). Growing Garlic in the Home Garden. New Jersey Agricultural Experiment Station. Retrieved October 24, 2023, from https://njaes.rutgers.edu/fs1233/ 

Fuller, D., & Johnson, S. B. (2022). Growing Garlic in Maine. University of Maine Cooperative Extension Publications. Retrieved October 24, 2023, from https://extension.umaine.edu/publications/2063e/ 

Moyer, M. M. (2015, February). Diseases of Garlic: Various Pests. Cornell University College of Agriculture and Life Sciences. Retrieved October 24, 2023, from http://plantclinic.cornell.edu/factsheets/garlicdiseases.pdf 

Sideman, B. (2016, April). Growing Garlic in New Hampshire. University of New Hampshire Extension. Retrieved October 24, 2023, from https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource006097_Rep8611.pdf 

Stewart-Courtens, C. (2012, August 7). Harvest Considerations for Garlic. Cornell Cooperative Extension Eastern New York Commercial Horticulture. Retrieved October 24, 2023, from https://enych.cce.cornell.edu/submission.php?id=88&crumb=crops|crops|garlic|crop*14