Garlic IPM Newsletter No. 12 — July 10, 2025
Southern Maine Garlic Ready to Harvest Soon
Garlic throughout southern and midcoast Maine will be ready to harvest within the next few weeks. Other New England states are reporting slightly earlier garlic harvests than usual due to environmental conditions. The best way to know garlic is ready to harvest is to dig up several bulbs and cut them in half cross-wise to ensure they are filled out. This often coincides with when the lower third to half of leaves have died back. If harvest is too late, wrapper leaves will also die back, allowing cloves to splay apart from the neck and thus reduce storage life and marketability.
Proper harvesting and curing is crucial for a high quality garlic crop. Loosen bulbs with a fork, as simply pulling on tops may damage necks. Garlic can be left outside to dry for a day or so, but should not be exposed to full sun at any point during the curing process because this can result in a condition called waxy breakdown.
Cut tops to a manageable size (6-8″) and move the crop to a dry, well-ventilated curing area for 10-14 days. Note that high tunnels and greenhouses can be too hot for curing garlic. It is important to handle plants gently to avoid bruising bulbs. Lay plants in a single layer on wire racks or hang them in bundles. When plants are fully cured, the central stalks will be fully hardened, wrapper leaves will be dry and crispy, and the neck will be constricted and fully dry. This is critical for preventing the movement of pathogens into the bulb during long-term storage.
Once fully cured, tops can be cut to 1″, roots should be closely trimmed back, and excess soil can be brushed off gently. Leave as many wrapper leaves as possible and do not wash bulbs unless markets demand it. With excellent airflow and storage conditions (30-32°F with 60-70% relative humidity), well-cured garlic will keep 6-7 months. Seed stock, on the other hand, should be kept at 50°F and similarly low relatively humidity.
Waxy breakdown appears as amber yellow cloves with compromised texture, and in severe cases may be visible on the entire bulb when wrappers cling to shrunken cloves. This occurs when mature bubs are exposed to high temperatures – right before or at harvest, and sometimes even during curing. There is an excellent picture of waxy breakdown on garlic on a blog post by Cornell Cooperative Extension.
Maintaining good ventilation with mesh or wire racks and airflow will both moderate temperatures and hasten curing. The faster garlic cures, the less time it will be vulnerable to pathogens that may reduce storage life of the crop. Keep plants in a single layer at warm (not hot) temperatures and low relative humidity.
Thrips and Other Insect Pests
Onion thrips populations have grown at scouting locations where controls haven’t been applied, but not to numbers that surpass action thresholds. If onion thrips numbers in your field are over threshold at this point, be sure to consider the pre-harvest interval of the material you use, as many conventional products have PHIs upward of one week.
| Scouting Location | Thrips (per leaf) as of July 8, 2025 |
|---|---|
| Buxton | 0.05 |
| Monmouth | 0.92 |
| Topsham | 0.16 |
| Washington | 0.45 |
No other allium insect pests have been observed this season in our scouting. Please remember to keep an eye out for leek moth and allium leafminer as garlic harvest nears and as other allium crops continue to grow, and contact Peyton Ginakes with suspected infestations.
Peyton Ginakes, PhD
Research Associate
University of Maine Cooperative Extension
Highmoor Farm
52 US-202
Monmouth, ME 04259
(207) 933-2100
This project is funded by a Specialty Crop Block Grant through the Maine Department of Agriculture, Conservation, and Forestry. Funding for the Maine 2024 Specialty Crop Block Grant Program was made possible by a grant/cooperative agreement from the USDA Agricultural Marketing Service. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USDA.
Where brand names or company names are used, it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
The University of Maine System is an equal opportunity institution committed to nondiscrimination.