Jeff Green | Aug 13, 2009
Back to HomeMaster Gardeners - August 13, 2009 Harvesting garlic and onionsby Dale Odorizzi, Lanark County Master Gardeners While garlic and onions are growing in the ground, they look very similar. Almost from the moment they sprout, they can be used in the kitchen. The real difference in their harvest takes place if you want to store your crops over the winter.
Garlic harvest takes place sometime from the first week in July to about the middle of August, depending on the variety. If you lift your bulbs too early, they will be undersized and not store well; too late and they will lack the protective paper-like wrapping around the bulbs. Watch the leaves. The green leaves start to die from the bottom up. When the bottom three or four leaves are dead and the top five or six are green, it is time to lift the bulbs. If you are not sure, dig a bulb or two and check. A mature bulb is fully swelled, well-sized and has some partially decomposed wrappers. Pick a dry day for harvesting.
Garlic is very fragile and should not be bumped, bounced or dropped as even the smallest bump will bruise the garlic, causing early decay and loss of quality. Carefully lift the bulbs with a garden fork and take them, greens and all, for cleaning and curing. Don’t leave garlic in the hot sun but move it quickly to a shady spot to avoid 'cooking'. If your soil is a sandy loam, any dirt can be gently brushed off. Clay soils tend to adhere to the bulbs and may need to be washed off with a gentle spray of fresh water. Trim roots to 1/4" and carefully remove any dirt from the roots.
Garlic needs about two weeks to cure in order to prepare it for winter storage. Either hang it in bundles of 10-12 or place on mesh racks in an airy, ventilated drying shed. Your carport or barn works well for this purpose. Ensure a good airflow and protection from direct sunlight. Once your garlic is cured, trim it to remove stalks and take it to storage. It can also be braided for convenience of storage and use. Best storage temperatures are low, 0-30C, or room temperature, 15-220 C, at low humidity. Never store garlic in the refrigerator as temperatures of 5-100C will start premature growth. I have found room temperature works best. Different strains and varieties of garlic have different storage lives, varying from six months for 'pickling' garlic to as long as 11or 12 months for some of the soft-neck strains.
Onions are ready for harvest when the necks are reasonably dry and about 10 days after the tops have fallen over. This is later than garlic, at my house usually sometime in September. Harvest onions when the weather is dry; harvesting after a rainfall, or when the humidity is high, increases susceptibility to post-harvest disease. At harvest, bulbs must be firm, with mature necks and scales, and must be a good size. Discard defective onions (i.e. sprouted, insect damaged, sunscalded, green, bruised). I dry my onions for a few days in the field, in the sunlight. If frost threatens, I cover them overnight. This curing decreases the incidence of neck rot, reduces water loss during storage, prevents microbial infection and is desirable for development of good colour.
The optimum temperature for long-term storage of onions is 0°C with 65-70% relative humidity. To ensure a storage life of up to eight months, onions must be promptly stored after curing. Exposure to light after curing will induce greening of the outer scales.
With a little care, you can enjoy your onions and garlic all winter long. In early July, as I am writing this, I still have firm onions and garlic from last year in storage. Some of my onions have sprouted but a few firm ones remain.
For more gardening information, call Helen Halpenny at 613-256-3219.