Harvesting Alliums (onions, garlic and relatives)

Onions curing and drying in strings.
Credit Southern Exposure Seed Exchange

The allium family includes all kinds of onions, garlic, leeks, perennial onions such as potato onions, and also less well known alliums, mostly perennials.

This is the time of year for harvesting most alliums except leeks. (It’s the time for planting out leeks for fall and winter harvests.)

I have a whole series of Alliums for the month posts. Here’s a link to Alliums for June. It includes the starter for the list I provide here, of the relative timing of harvests for various alliums.

Order of Allium Harvests

Our allium harvests generally occur on these dates. Your dates will differ but you can expect this order of harvests:

  1. Nov 18–May 10: Onion scallions in the hoophouse
  2. Mar 15–May 31: Garlic scallions
  3. May 7–May 28: Garlic scapes
  4. May 10–Jun 30: Onion scallions outdoors
  5. May 25–Jun 10: Green bulb onions (Allium cepa)
  6. May 30–Jun 8: Hardneck garlic
  7. May 30–Jun 11: Potato onions ( cepa aggregatum) planted in fall
  8. Jun 6–Jun 25: Potato onions planted in January and February
  9. Jun 10: Shallot bulbs (cepa aggregatum), fall-planted. They are not fully hardy in zone 7a. I recommend storing bulbs and replanting in early spring instead
  10. Jun 11–Jun 12: Softneck garlic bulbs
  11. Jun 11–Jul 11: Bulb onions sown in fall, with slow spring-sown ones to Jul 26
  12. Jun 19–Jul 2: Cipollini (cepa cepa) Small bulb onions grown in a hoophouse from spring transplants
  13. Jun 30–Jul 5: Elephant garlic ( ampeloprasum ampeloprasum) We stopped growing this when too many winter-killed
  14. Jul 1–Jul 8: Shallots from bulbs refrigerated over the winter and replanted in early spring
  15. Jul 1–Jul 15: Cipollini outdoors from spring transplants
  16. July: L’itoi (A. cepa aggregatum). This peppery little perennial clumping onion sends up edible shoots in early July.
  17. Jul 4–Jul 30: Shallots from seed started in late January, plugs transplanted in March. Harvest 4–8 weeks later than those from bulbs replanted in October
  18. July–September: The small red-purple bulbils of Egyptian onions can be pickled. Earlier in the year, before the bulbils appear, harvest the tasty, succulent leaves of this very hardy perennial.
  19. Spring, summer, fall according to size: Welsh onions ( A. fistulosum) are non-bulbing, hardy perennial onion greens, larger than chives and scallions. Japanese bunching onions are similar. Can be sown in fall or spring. Clumps can be divided and replanted
  20. Sep 6: Shallots direct sown outdoors in February and March

Here’s some details on harvesting some of the smaller alliums

Harvesting onion scallions

Scallions ready-to-harvest.
Photo Pam Dawling

From around May 10, through June, our outdoor onion scallions are big enough to harvest (just as the hoophouse ones finish up!) We start these from seed in January and February and transplant as clumps in March and April. In cooler climates, you can schedule harvests through summer, but we cannot get good quality ones here after late June. It’s good to develop an efficient harvest method with little scallions or it takes way too long. To harvest, loosen the soil with a digging fork, then lift out a clump. Deal with scallions in bunches as much as possible, rather than one at a time. Shake the plants, and trim off the roots and the ragged tips. Holding the bunch in one hand, pass the scallions one at a time to the other hand, separating them and pulling off a single outer leaf, not more. Don’t fuss with them too much. Next set the scallions in water in a small bucket, to clean themselves while you work on the rest. If you are going to band them, start out with a bunch of rubber bands around three fingers on the hand that holds the bunches (leaving the forefinger free for tasks demanding dexterity). When you’re ready to band them, use the other hand to pull a rubber band into position. When the bucket is full enough, dunk the scallions up and down, and transfer them to a clean bucket with a small amount of water to keep them fresh.

Harvesting garlic scallions

A healthy patch of garlic scallions in spring
Photo credit Kathryn Simmons

Garlic scallions (small whole garlic plants) provide our first allium harvest of the calendar year, starting in mid-late March and continuing (if we have planted enough) into May. Some people cut the greens at 10″ (25 cm) tall and bunch them, allowing cuts to be made every two or three weeks. We prefer to simply lift the whole plant once it reaches about 7″–8″ (18–20 cm) tall. You may need to loosen the plants rather than just pulling. The leaves keep in better condition if still attached to the clove. Trim the roots, rinse, bundle, set in a small bucket with a little water, and you’re done! Garlic scallions can be sold in bunches of three to six depending on size.

Harvesting garlic scapes

Harvesting garlic scapes
Photo by Wren Vile

Another spring allium harvest is garlic scapes (the firm, edible flower stems of hardneck garlic).  Here scapes appear when tulip poplars flower. In a warm spring, that can be the end of April. Garlic scape arrival is partly temperature dependent. We harvest scapes two or three times a week for about three weeks, until there are no more. At the Roxbury Agriculture Institute at Philia Farm in New York State, they wait until the scape has curled round, then cut it off. We harvest ours sooner than that, in order to let the bulb grow as big as possible. We pull our garlic scapes to get the most out ! In our climate, the appearance of scapes indicates the garlic will be ready to harvest in three weeks. I’m not sure if the same timing works everywhere, so keep records and you’ll learn what to expect. Exactly how day-length and temperature interact as triggers for scape and bulb harvest dates, I don’t know. I’ve done some research, but haven’t found much solid info yet.  In general, plant flowering is triggered by some combination of enough vernalization (chilling hours — maybe 10 weeks below 40°F/4.5°C), plant maturity, temperature and photo-period (the relative length of day and night). In cold weather the plants suppress the flowering signal. The leaves perceive the amount of daylight, and when the temperature is also right, they trigger flowering by sending a signal (called Florigen) to the shoot tips. Florigen may be an actual compound, or may be some combination or ratio of several hormones produced by the plant. Almost all these factors are outside our control once the plant is in the ground, so the best we can do is pay attention and be ready to act.

Harvest garlic bulbs and bulbing onions

(see Alliums for June) I won’t go into details here, as I’ve done that previously.

240 heads of garlic drying in Tenax fencing.
Photo Sierran Farmer

Harvest small potato onions

produced by large ones planted in September.

Yellow Potato Onions.
Photo Southern Exposure Seed Exchange

Harvesting cipollini

(aka cocktail onions, boiling onions, pickling onions)

Red Marble cipollini.
Photo Fedco Seeds

These small, attractive onion bulbs can be easier to grow in marginal onion climates than full-sized onions or can be an additional allium crop. The larger ones can be used as fresh bunching onions. All may be cured. Cipollini naturally have more sugar than most onions, which makes them ideal for caramelizing or roasting whole. The scheduling and final size of your cipollini will depend on your latitude and temperatures.

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