Alliums for November: Plant garlic, sow onions in a hoophouse, eat leeks

Tadorna winter leeks in October.
Photo Pam Dawling

Cold-Tolerance of Alliums

Alliums are more cold-tolerant than most people believe. Here are my observations of killing temperatures for outdoor crops. Note that crops often survive night-time lows in the hoophouse that would have killed them outdoors.

  • 12°F (−11°C): garlic tops if fairly large, most fall or summer varieties of leeks (Lincoln,King Richard), large tops of potato onions
  • 10°F (−12°C) some leeks (American Flag aka Musselburgh and Scottish Flag, Jaune du Poiteau)
  • 5°F (−15°C): garlic tops if still small, some leeks (Bulgarian Giant, Laura, Tadorna, Bandit), some bulb onions, potato onions and other multiplier onions
  • 0°F (−18°C): chives, garlic, a few leeks (Alaska, Durabel); some bulb onions, yellowpotato onions, some onion scallions (Evergreen Hardy White, White Lisbon), Walla Walla onions sown in late summer (with rowcover for winter)

Planting Garlic

Planting garlic.
Photo Brittany Lewis

You can see my garlic slideshow for more info. I was surprised to find I haven’t written much in my blog about planting garlic, so here goes! See the alliums chapter in Sustainable Market Farming for more on types, varieties, and garlic genetics. The information here comes form that chapter.

When to Plant Garlic

Plant when the soil temperature at 4″ (10 cm) deep is 50°F (10°C) at 9 am. If the fall is unusually warm, wait a week. Instructions from Texas A&M say less than 85°F (29°C) at 2″ (5 cm) deep. We plant in early November. In New Hampshire, mid-October is the time. The guideline for areas with cold winters is 2-3 weeks after the first frost but before the ground freezes solid for the winter. In Michigan, planting time is 6 weeks prior to the ground freezing, giving enough time for root growth only, to avoid freezing the leaves. In California, garlic can be planted in January or February.

Both hardneck and softneck garlic do best when planted in the fall, though softneck garlic may also be planted in the very early spring if you have to (with reduced yields). If you miss the window for fall planting, ensure that your seed garlic gets 40 days at or below 40°F (4.5°C) in storage before spring planting, or the lack of vernalization will mean the bulbs will not differentiate (divide into separate cloves).

Garlic shoots emerging from the mulch a few weeks after November planting. Photo Twin Oaks Community

Garlic roots will grow whenever the ground is not frozen, and the tops will grow whenever the temperature is above 40°F (4.5°C). In colder areas the goal is to get the garlic to grow roots before the big freeze-up arrives, but not to make top growth until after the worst of the weather. In warmer areas, the goal is to get enough top growth in fall to get off to a roaring start in the spring, but not so much top growth that the leaves cannot endure the winter. If garlic gets frozen back to the ground in the winter, it can regrow and be fine. If it dies back twice in the winter, the yield will be lower than it might have been if you had been luckier with the weather. When properly planted, it can withstand winter lows of –30°F (–35°C). If planted too early, too much tender top growth happens before winter. If planted too late, there will be inadequate root growth before the winter, and a lower survival rate as well as smaller bulbs.

How Much Garlic to Plant

A yield ratio of 1:6 or 7 seems typical, and makes complete sense when you consider you are planting one clove to get a bulb of 6–7 cloves. Divide the amount you intend to produce by six to figure out how much to plant. For large areas 750–1,000 lbs/ac (842–1,122 kg/ha) are needed for plantings in double rows, 3″–4″ in-row (7.5–10 cm), beds 39″ (1 m) apart. For single rows, 8 lbs (3.6 kg) of hardneck or 4 lbs (1.8 kg) of softneck plants about 100′ (30 m). In the US, one person eats 3–9 lbs (1.4–4.2 kg) per year.

Popping garlic cloves in preparation for planting
Photo  Southern Exposure Seed Exchange

Popping Garlic Cloves for Planting

The garlic for planting should be taken apart into separate cloves 0–7 days before planting. We are doing this on November 7, along with our crop review meeting when the crew meets to make notes on the past season. This task is a good group activity. Twist off the outer skins and pull the bulb apart, trying not to break the basal plate of the cloves (the part the roots grow from), as that makes them unusable for planting. With hardneck garlic, the remainder of the stem acts as a handy lever for separating the cloves. We sort as we go, putting good size cloves in big buckets, damaged cloves in kitchen buckets, tiny cloves in tiny buckets and outer skins and reject cloves in compost buckets. The tiny cloves get planted for garlic scallions. Don’t worry if some skin comes off the cloves — they will still grow successfully. Cloves for planting should be from large (but not giant) bulbs and be in good condition.

Click the link to read about hot water treatment for seed garlic at WeeBee Farms. 

Pre-plant Seed Garlic Treatments

Many of us do nothing special with the cloves before planting, but if you have pest and disease problems, use pre-plant soaking treatments, usually done the night before planting. Some growers find they get better yields from treated cloves even if no problem was obvious.

To eradicate stem and bulb (bloat) nematode (Ditylenchus dipsaci), soak the separated cloves for thirty minutes in 100°F (37.7°C) water containing 0.1% surfactant (soap). Or soak for twenty minutes in the same strength solution at 120°F (48.5°C), then cool in plain water for 10-20 minutes.

Allow to dry for 2 hours at 100°F (37.7°C) or plant immediately. Anytime your garlic grows poorly and you can’t tell why, send a sample with the soil it’s growing in to your Extension Service to be tested for nematodes. Mites can eat the skins of the cloves, survive the winter and multiply all spring long, seriously damaging or even killing your crop. To kill mites (which hide between the wrappers) before planting, separate the bulbs into cloves and soak them overnight (up to 16 hours) in water.

Possible additions to the water include one heaping tablespoon of baking soda and one tablespoon of liquid seaweed per gallon (around 8 ml baking soda and 4 ml liquid seaweed per liter). Just before planting, drain the cloves and cover them in rubbing alcohol for three to five minutes, long enough for the alcohol to penetrate the clove covers and kill any mites inside. Then plant immediately. The long soaking will loosen the clove skins so that the alcohol can penetrate. Mite-infested garlic soaked like this does much better than unsoaked infested garlic. The solution used to kill mites can also be used to kill various fungal infections. The cloves need only fifteen to thirty minutes soaking.

In trials comparing treated and untreated cloves, treated cloves were larger and healthier than untreated ones. Fusarium levels can be kept down by adding wood ashes when planting and then possibly dusting the beds with more ashes over the winter (use moderation — don’t add so much that you make the soil alkaline). Or you could soak the cloves in a 10% bleach solution, then roll them in wood ash (wear gloves for handling ashy cloves). The wood ash soaks up the dampness of the bleach and provides a source of potassium. This information came from the Garlic Seed Foundation. Join GSF to find out all the details!

Other November Allium Planting

Plant shallot bulbs before the end of November and medium-sized potato onions (1.5″ – 2″, 4-5 cm) at the end of November or early December in zone 7. Finish dividing and replanting perennial leeks and Egyptian walking onions this month

Young onion plant in March.
Photo Kathryn Simmons

Special Allium Topic for November: Sow Bulbing Onions in the Hoophouse

We developed a system of growing onion starts in our hoophouse over the winter and transplanting them bare-root outdoors in very early March. I wrote about choosing onion varieties for your latitude last month. There I explained that to grow big onions we need to have large transplants on March 1, so we can have big vegetative plants before bulbing is triggered by the daylength.

The method involves making two sowings of bulbing onions, each enough for the whole planting. This provides insurance in case one date turns out better than the other. Then we follow this up with a partial third sowing to make up numbers of any varieties that didn’t germinate well. We make our first sowing November 10, our second November 20, and a third on December 5 as a back-up in case of problems. Our formula is: divide the number of onion plants wanted by 20, to give minimum length of row to sow, in feet. And sow this amount twice, 10 days apart. The onions will be planted out at 4″ (10 cm) apart. We add 20% to provide some slack. For a final row of 100′ (30.5 m), we’d need 100′ × 3 per foot × 1.2 (adding 20%) plants. 360 plants. We sow 3 seeds per inch (approx. 1 cm apart), 36 per foot (30 cm). At this sowing rate, we need 120″, or 10′ (3 m).

See The Year-Round Hoophouse for more on growing onions this way. If we find ourselves with extra onion plants in March, we usually re-categorize them as scallions. But we have also transplanted them in early March in a single row along the south edge of hoophouse beds, for an early crop. We got good onions but they dwarfed the pepper plants behind them. Maybe planting them on the north side of the bed is better?

Trimming roots from a leek in December.
Photo Pam Dawling

Storing Leeks

I wrote about how to dig up leeks last month. In zone 7 we leave our leeks in the ground till we need them, being sure to harvest the less hardy Lincoln and King Richard first. We use a walk-in cooler for short term storage (up to a week) and keep the root ends in water. Leeks are best stored at 33°F (0.5°C) and 65% relative humidity. In colder zones, leeks can be harvested and stored in a root cellar or basement. This is helpful in areas where the ground freezes solid for weeks on end. You can store leeks with the roots packed in soil, shoulder to shoulder in a crate or box in a root cellar, where they will keep for six weeks. They can be stored in plastic bags for two to three months at the right temperature, or frozen. Another possibility is to leave them in the garden, mulched with a foot (30 cm) of straw or hay as well as rowcover, if temperatures are below 10°F (–12°C). Our winter temperatures fluctuate a lot, so covering in-ground crops with mulch doesn’t work well for us.

Young greens in the hoophouse, nematodes, upcoming events

Young senposai transplant in our hoophouse.
Photo Pam Dawling

After the set-backs with our winter hoophouse greens  transplants that I wrote about last week, we worked really hard and got the whole house planted up. Most of the transplants have recovered from their transplant shock (wilting each day), during the cloudy weather we had.

The new seedlings are coming up fast and calling on us to thin them. We ended up not needing so many of the Plan D plug flat plants, but we’ve kept them for now “in case” .

Young Tokyo bekana transplant in our hoophouse .
Photo Pam Dawling

Ultimately if we don’t need them, they’ll go in a salad mix. I wrote about making salad mix last year. The past two days I have been able to harvest a mix in the hoophouse. The ingredient we are shortest of is lettuce. My first mix was spinach, Bulls Blood beet leaves, a few leaves of Tokyo Bekana, Bright Lights chard, Scarlet Frills, Ruby Streaks and Golden Frills, and a handful of lettuce leaves. Red Tinged Winter is growing fastest, of all the varieties we planted this year.

Ruby Streaks transplant in our hoophouse. Compare with Scarlet Frills below.
Photo Pam Dawling

Golden Frills mustard transplant in our hoophouse. I harvested a leaf for salad mix yesterday.
Photo Pam Dawling

Scarlet frills mustard in our hoophouse. Notice that this crop is frillier than Ruby Streaks.
Photo Pam Dawling

The mix I made today had fewer ingredients. I left the frilly mustards, the lettuces and the Tokyo bekana alone to grow some more. I used Bulls Blood beets, spinach, tatsoi outer leaves and a few Bright Lights chard leaves and stems.

Cucumber roots with nematodes (see circles).
Photo Pam Dawling

I have a new Mother Earth News blogpost, about the nematodes in our hoophouse. And I’m preparing a new slide show for the Carolina Farm Stewardship Association conference. See my Events page for details

For those of you on other social media, here are their handles and links (use the hashtag #CFSAC2018).

This week we will be popping garlic for planting and having our Annual Garden Crop Review meeting. Next week I’ll tell you more about garlic planting as part of the Alliums for November post.

Popping garlic cloves in preparation for planting
Photo credit Southern Exposure Seed Exchange

Alliums for October: plant perennial alliums; harvest fall leeks, eat onions and garlic from storage, choose bulb onion varieties

Fall leek varieties have yellower-green foliage than winter leeks and reach size in less time. We eat ours in October and November. Photo Bridget Aleshire

This is the sixth in my monthly series of Alliums for the Month posts, which run from May to April.

Plant various perennial alliums in October

Plant shallot bulbs between October and November, if your winters aren’t too cold. Mulch them well. We tried to over-winter replanted shallot bulbs, but we got lots of winter-kill. To save bulbs for replanting in early spring, refrigerate them. You can alternatively start shallots from seed in late January in zone 7 and plant in spring.

Divide & replant Egyptian onions & perennial leeks September-November. Plant perennial leeks from dry bulbs a month earlier than divisions: August-October. Perennial leeks take 9-12 months to grow to a good size.


Harvested leeks.
Photo Small Farm Central

Harvest fall leeks in October (and November)

Common leeks are Allium ampeloprasum var. porrum. Leeks come in two main types: the less cold-hardy, faster-growing fall varieties, often with lighter green leaves, which are not winter-hardy north of Zone 8, and the blue-green hardier winter leeks. In the first category, we like Lincoln (50 days to slender bunching leeks, 75 days to mature leeks), King Richard (75 days, fast-growing) and Giant Bulgarian. American Flag has not worked well for us. Giant Musselburgh (105 days) is bolt-resistant, for overwintering in milder climates. For winter leeks we like Tadorna (100 days), Jaune du Poiteau, King Sieg (84 days, a cross between King Richard and the winter-hardy Siegfried, from Fedco) and Bleu de Solaize (105 days, very hardy).

Leeks can be harvested whenever they seem big enough. To feed a hundred people, we like to have one bed of 1080 leeks for harvesting each month, from October to February. We grow two beds of fall leeks and three of winter-hardy ones. About ten leeks each, each month.

When harvesting leeks, remember how deep you planted them and try to avoid spearing them. Put the tines of a digging fork (spading fork) vertically down in the ground 2″–3″ (5–8 cm) away from the leeks. I try to dig up two at once for efficiency. Step on the fork and lever back until the leeks move. Impatient pulling of unloosened leeks leads to broken ones. Remove one leek, chop off the roots, invert the plant and cut the leaves in a V shape, so that the tougher outer leaves are shortest and the younger inner leaves are longest. Clean up any obviously inedible outer layers, then put the leek in a bucket. We put an inch (2.5 cm) of water in the bottom of the bucket (to keep the leeks hydrated) before taking the leeks to the cooler. If the ground is frozen too deep to pierce the crust with the fork, you may be able to harvest a few leeks for immediate use by pouring boiling water along the row at the base of the plants. This does not seem to damage the leaves.

Read about the early summer task of planting leeks here.

Other October allium harvests

Harvest and eat large perennial leeks, and leaves of Egyptian onions and smaller perennial leeks September –April, whenever they are large enough.


Australian Brown onions.
Photo Southern Exposure Seed Exchange

Eat onions and garlic from storage

Eat the non-storing onions and the hardneck garlic first. Sort through your bulb onions once a week or so, removing any that are having troubles, before the trouble spreads to other bulbs. Then work your way through the non-storing varieties such as Ailsa Craig, Walla Walla, etc.

Silverskin softneck garlic varieties store up to 12 months under the best conditions. Most softneck garlic stores for longer than the 4-6 months that most hardnecks will. (Music and Chesnok Red can keep 7 months or more here in central Virginia.)

Read more about garlic and onion storage in the September Allium of the Month post. Here’s the headlines:

  • Not too dry, not too damp.
  • Above 60–70°F (15.5–21°C) or below 40°F (4.4°C) for garlic; 60–90°F (16–32°C) or below 41°F (5°C) for bulb onions. Do not freeze. (Chilling injury at 31°F)
  • Avoid 40–56°F (4.4–13°C) for garlic, avoid 45–55°F (7–13°C) for bulb onions

Other resources on harvesting, curing and storing alliums

Garlic Harvest, Curing and Storage https://ag.umass.edu/vegetable/fact-sheets/garlic-harvest-curing-storage

Onion Harvest and Storage https://ag.umass.edu/vegetable/fact-sheets/onions-harvest-curing

Alliums, Post Harvest and Storage Diseases https://ag.umass.edu/vegetable/fact-sheets/alliums-post-harvest-storage-diseases

Special Allium Topic for October: Choosing bulb onion varieties

Regular bulb onions are a biennial crop grown as an annual (A. cepa var. cepa). This botanical group includes bulb onions, scallions (spring onions, salad onions or escallions), and the small pickling onions (cipollini).

A fine bed of onions in spring.
Photo Kathryn Simmons

In our location the best time to sow bulbing onion seed is early November in our hoophouse. After over-wintering, we transplant them outdoors at the very beginning of March. (More on sowing onions next month.) If you want to sow in November as we do, now is the time to choose varieties. Factors include latitude, temperature, flavor preference and whether or not you hope to store onions or only grow for fairly immediate eating.

Latitude

Onions have three separate phases of growth — vegetative, bulbing and blooming — and the switch from one phase to the next is triggered by environmental factors, mostly day-length and temperature. To grow large bulb onions it is important to produce large healthy plants before the vegetative stage gives way to the bulbing stage. If plants are small when bulbing starts, only small bulbs can result.

Be sure to choose varieties suited to your latitude, because onions are daylength sensitive. Varieties are classified as short day, intermediate day, or long day types, depending on the daylight length at which they start forming bulbs (assuming suitable temperatures): 10-12 hours, 12-14 hours, 14-16 hours. Onions bulb earlier at warm temperatures than at colder temperatures. More catalogs are now including the information on the latitude adaptation of their varieties.

The further north you are, the more hours of daylight you have in summer. Here, our longest day (summer solstice) has 14 hours and 46 minutes of daylight. We have 14 hours of daylight six weeks earlier, on May 6. A few varieties of long-day onions can be grown here, but those requiring 15 or 16 hours of daylight will never form bulbs at this latitude. South of their ideal growing region, long-day onions don’t start bulbing until triggered by the very longest days (near summer solstice) and the bulbs get too hot in July as they mature.

Short-day onions start to bulb at 10–12 hours of daylight, provided temperatures are warm enough. If short-day onions are grown too far north (where it is too cold to overwinter them, and they must be started in spring) they will bulb before much leaf growth has occurred, and so the bulbs will be small. At our latitude (38°N) neither long-day nor short-day onions are ideal.

Temperature – avoiding bolting onions

The trigger for the transition from bulbing to flowering (bolting) is temperatures below 50°F (10°C) for three to four weeks, after the plants have six leaves or more (pencil size). This is especially true when rapid growth is followed by a period of cool weather. The chilling effect appears to be cumulative over time. Hence you can see that to avoid bolting it’s important your seedlings don’t get too big too early in the winter. And that you give them extra protection if there is a long cold spell in spring before you plant them out. Daylength does not affect bolting.

For us to succeed with bulbing onions we need to produce transplants the thickness of thin pencils (⅜” or 1 cm) on March 1, our earliest possible date for planting outdoors. This gives the plants time to grow large before bulbing is triggered. Starting from seed in January didn’t give us time to grow big vegetative plants, therefore not big bulbs either. Starting plants in the fall and keeping them in coldframes or outdoors under rowcover gave us too much winter-kill. Once we discovered the method of using our hoophouse to keep little onions alive over the winter we were very happy.

We have sown bulbing onions for growing to maturity in the hoophouse, and, more often, we have grown onion seedlings for planting outdoors.

Other factors in choosing onion varieties

“Days to maturity” numbers in catalogs are generally for spring planting once conditions have warmed to the usual range for that crop. When growing late into the fall, add about 14 days for the slowdown in growth, and when growing over the winter, precise calculations go out the window!

Beware of white onions, which can get sun-scald, if growing them to maturity in a hoophouse.

Walla Walla onions
Photo Southern Exposure Seed Exchange

Varieties for storage and fresh eating

We have to accept that hard storing onions cannot be grown in the south. At 38°N, some varieties that worked well for 6 month storage for us include: Gunnison, Frontier, Copra as the best three, then Patterson (Hybrid. High yield potential. 38°–55° latitude) and Prince. Prince has since been replaced by Pontiac, a large onion with strong skin, thin necks, suitable for 36°–50° latitude. We had only 50% success with Red Wethersfield and Cabernet. Some non-storing good ones for us include Ailsa Craig (OP aka Exhibition. High yield. Large. 33°–40° latitude), Walla Walla, Olympic, Bridger (Hybrid. Replaces Olympic. 35°–50° latitude), Expression. Varieties come and got. Australian Brown is one that sounds good, but I have not tried it.

More info on bulb onions

See Sustainable Market Farming for more on onions in general, including diseases.

See the Texas A&M AgriLife Extension publication Onion, by Joe Masabni. I don’t endorse the chemical pesticides mentioned, but the information on growing onions is very sound.

Alliums for September: plant potato onions, sow ramps, eat Welsh onions, move stored garlic

Potato onion plant with young shoots.
Photo by Kathryn Simmons

Alliums to Plant in September

Divide and replant Egyptian onions and perennial leeks

Divide and replant perennial alliums in September (August-October) to increase the size of the patch and get more next year.

Plant large potato onions (2-2½”, 5-6 cm)

  • It’s better not to try to store very large potato onions over 2½” (6cm) for planting, just eat them (they sprout easily).
  • All large potato onions store poorly, so keep planting stock in the refrigerator until planting in late September or early October. Jeff McCormack does not recommend planting before September.
  • For 360′ (110m) @ 8″ (20cm) you need 540 bulbs plus 30%-40% spare. Approximately 760 bulbs. 150 large bulbs weigh about 25# (11kg)
  • Plant them at 8″ (20cm). If there are not enough large onions available, increase spacing or fill out with medium onions.
  • Cover with ½-1″ (1-2cm) soil, and add 4″-8″ (10-20cm) mulch.
  • Refrigerate any leftovers for November planting with the medium-sized onions, or eat or sell now.
  • Yields can be 3 to 8 times the weight of the seed stock, depending on growing conditions.
  • Individual bulbs can be grown indoors in a pot to produce a steady supply of green onions during the winter.

Sow ramp seeds in woodlands

Mature harvested ramp plants.
Photo Small Farm Central

In zones 3-7, sow ramps seed during August and September (see August blogpost)

Ramps (also known as Wood Leeks or Wild Leeks) are a native woodland perennial, and can be found throughout the eastern-half of the United States, as far west as Oklahoma and as far north as the central and eastern provinces of Canada.

Ramps, (Allium tricoccum) have some of the flavor components of leeks, onions, and garlic. There are projects to re-establish ramps in a number of regions in the Eastern United States.  Carriage House Farm is one such attempt by Grow Appalachia, which is a program of Berea College in Kentucky, Grow Appalachia works with farmers, gardeners, ranchers, and conservationists across a five state area to reintroduce old native and heirloom species of plants.  Ramps is/was one plant in this program. It takes two years for ramp seeds to germinate and another 2-3 years till they hit harvestable levels.

Having Your Ramps and Eating Them Too is a book by Glen Facemire

Alliums to harvest in September

Harvest Egyptian walking onions (topset onions, tree onions) for pickling, leaves of Egyptian onions and perennial leeks (September-April for cutting those)

Egyptian onions produce tiny red-purple bulbs in the umbel instead of flowers, and were previously named Allium cepa var. proliferum. According to Wikipedia, they are now known to be a hybrid of A. cepa and A. fistulosum.

Japanese bunching onion and Welsh onion (native to China, not Wales) are Allium fistulosum. They are sometimes used as scallions, as are some A. cepa bulbing onions. Young plants of A. fistulosum and A. cepa look very similar, but may be distinguished by their leaves, which are circular in cross-section in A. fistulosum rather than flattened on one side.  A. fistulosum has hollow leaves (fistulosum means “hollow”), scapes and does not develop bulbs – the leaves are the part that is eaten. Welsh onions are also known as cibol, chibbles (in Cornwall), escallion (in Jamaica), negi (in Japan), pa (in Korea), as well as green onions, salad onions, spring onions,. These general last names are also used for other kinds of onions where the leaves are the part eaten.

Perennial leeks are Allium Ampeloprasum. Common leeks are Allium ampeloprasum var. porrum (more about leeks in October and March). Elephant garlic is botanically a leek (A. ampeloprasum var. ampeloprasum).

Other Allium Tasks for September

See Alliums for August for more on all of the following jobs which continue into September:

  • Snipping and sorting garlic and potato onions
  • Trimming, sorting and storing bulb onions
  • Eating onions and garlic from storage
  • Inspect onions and garlic at least once a month. Remove bulbs which are sprouting or rotting or else the whole batch may spoil.
  • At the end of September I make the decision about how many potato onions to keep back for planting (see August for our calculations).
  • We also move garlic from warm storage to cool storage (more info below)

Potato onions store very well through the winter so long as they are well-cured, dry, well-ventilated, and not packed over 4″ deep. Ideal conditions are a temperature between either 32–41°F (0–5°C) or 50–70°F (10–21°C) with 60-70% humidity.

Polish White – our softneck garlic variety.
Credit Southern Exposure Seed Exchange

Special Allium Topic for September: Garlic Storage

Before trimming your garlic, I hope you were sure it was fully cured, and you set aside any non-storing bulbs, such as those with damaged cloves, or any over-mature, springing-open bulbs. It usually works to select your seed-stock bulbs at the same time.

Commercially, garlic is stored in the dark at about 32°F (0°C) and 65% humidity, and depending on the species and variety, it may keep six months or more. I have heard that garlic can be stored for up to nine months at 27°F (-2.7°C), but I have not tried that myself. It does not freeze until 21°F (-6°C). Do not store peeled garlic in oil, as garlic is low in acidity and the botulin toxin could grow.

For storage, garlic (like onions) does best with a humidity of 60%–70%. Refrigerators are usually more humid than ideal.

Garlic will sprout if kept in a temperature range of 40–56°F (4.4–13°C), or if it is allowed to get cold then warm. So long as temperatures remain over 56°F (13°C) you can store garlic almost anywhere. You can use an unheated room in your house, a root cellar, garage, etc. Maintain good air circulation. Most varieties store reasona­bly well in a cool room if hung from the ceiling in mesh bags, or spread on shelves in a layer less than 4″ deep.

In our climate, with a long period in the danger zone temperatures of 40–56°F (4.4–13°C), we keep alliums in the warmer storage range (60-70°F (15.5-21°C) or hotter) in a basement until late September or sometime in October when ambient temperatures in the basement drop close to 56ºF (13°C). We then move our eating garlic from the basement to the walk-in refrigerated cooler at 32–41°F (0–5°C), 95–100%. The low shelves in the cooler near the compressor are damper and do not work well. We use the high and dry shelves.

Juggling space for various crops, moving the garlic out of the basement makes space available for the winter squash harvests in September and October. By this time most of the apples from the walk-in cooler have been eaten, and space is available there. Also there is no longer the problem of ethylene emitted by the apples, which causes garlic to sprout. Ideally ripe fruits and garlic would never be in the same storage space.

Softneck garlics store longest. Silverskins store up to 12 months under the best conditions. Most hardnecks last 4-6 months but Music and Chesnok Red can keep 7 months or more here in central Virginia.

Storage of Seed Garlic

We store our seed garlic on a high shelf in the garden shed, at quite variable ambient temperatures, where it does fine until late October or early November when we plant it. Seed garlic does not require long-term storage conditions! The ideal storage conditions for seed garlic are 50-65°F (10-18°C) and 65-70% relative humidity. Storing in a refrigerator is not a good option for seed garlic, as prolonged cool storage results in “witches-brooming” (strange growth shapes), and early maturity (along with lower yields). Storage above 65°F (18°C) results in delayed sprouting and late maturity.

Siberian garlic.
Photo by Southern Exposure Seed Exchange

Alliums for August: plant perennial leeks, eat onion greens, sort potato onions again, move bulb onions into cooler storage

 

Perennial leeks.
Photo by Southern Exposure Seed Exchange

Plant perennial leeks (Oepri, Perlzwiebel)

These will be dry bulbs at this point of the year and can be re-spaced between August and October into a larger planting for next year.

August onion harvests

In cooler climates (if the quality is still good) the tops/greens/leaves of Egyptian onions and perennial leeks can be cut and used fresh. The larger bulbils of Egyptian onions and perennial leeks can be used in mixed pickles. Garlic and bulb onions can be eaten from storage.

Egyptian walking onions.
Photo by Southern Exposure Seed Exchange

Sort potato onions twice in August

Early August: at the third sorting of the potato onions, I separate the clusters, trim the tops and sort by size. Sorting by size is not essential, but I do it to help me figure out what to save for planting and what to eat or use as seed (for planting). We sort smalls (<1.5”), larges (1.5-2.0”) and eaters (>2.0”). And compost material. The rack space required after this stage is only a third of what it was before that.

At the end of August I sort through again, and make initial plans about what to do with surplus planting stock (sell, give to friends). At the end of September I make the decision about how much to keep back for planting. I used to put the onions into net bags for storage, but I found I get better results if I just leave them in a single layer on the racks. The small ones stay there till late January, through freezing conditions (or more accurately, alternating freezing and thawing conditions). They can appear to be frozen solid, but are in fine condition. Ideal conditions are 32-40F, 60-70% humidity, with good ventilation. Layers should not be more than 4” deep.

Yellow potato onions.
Photo by Southern Exposure Seed Exchange

Save seed-stock potato onions

Seed saving is a natural part of growing potato onions. We started in 2000 with 0.5 pound of seed stock, planted late in the spring. We harvested only 1.5#, but we continued, adding in more seed-stock, and planted 46# for 2003, (90’ large, 180’ small). At that point I was dividing into 3 planting sizes: small (<1”, 30-60 bulbs/pound); medium (1-1.5”, 16-22 bulbs/pound); and larges (>1.5”, 7-8 bulbs/pound). For 2004, I planned to plant large:small in a 1:2 ratio by area, to get enough small and medium onions to plant the same area the next year, and to get lots to eat as well. But the 2003 harvest had a high amount of large onions, and I decided to plant them all, increasing to 540’. We expanded to plant 720’, in a large:small ratio of 1:3 by area (i.e. 180’ large, 540’ small). This gives us enough smalls to plant for the next year, and plenty of larges and eaters. Someone growing for maximum seed-stock would probably want to plant a higher ratio of large ones, in order to get more smalls.

Instead of weighing all the onions, I now know I need to save 3 racks (probably 65#, 450 bulbs) of larges (1.5-2.0”) and 5 racks (probably 75#, 2100 bulbs) of smalls (<1.5”) for planting next year’s crop. This allows a margin for decay. The small ones really are very stable, it’s the larger ones that are more prone to sprouting, so I pull those out whenever I pass by.

Australian Brown storage onion.
Photo by Southern Exposure Seed Exchange

Move bulb onions into cooler storage

  • In July I mentioned that bulb onions can safely be stored at 60°F-90°F (16°C-32°C) if they have not been refrigerated at all. This applies only to fully cured onions with dry necks. (Green onions need refrigeration at 32°F-41°F (0-5°C), 95-100% humidity.)
  • For cured dormant onions it is very important to avoid the 45°F-55°F (7°C-13°C) range, because that’s when they sprout.
  • For storage, onions and garlic do best with a humidity of 60%-70%. Refrigerators are usually more humid than ideal. If you have a barn with the right temperatures, that will work better for long-term storage.
  • In our climate, with a long period in the danger zone temperatures, we keep alliums in the warmer storage range in a barn, shed or basement until ambient temperatures drop close to 55ºF, and then move them to a refrigerated cooler at 32°F -41°F (0-5°C) 95-100% humidity.
  • Do not freeze: onions get chill injury at 31°F (-0.5°C)
  • If at all possible, do not store onions with fruits, including squash, as these exude ethylene which promotes sprouting.

More reading

Other southern onion growers might like to read this publication by Dr Joe Masabni of Texas AgriLife Extension, called simply Onion

Walla Walla large non-storage onion.
photo by Southern Exposure Seed Exchange

Collect ramp seeds

If you have been wild-crafting ramps (more on that in March), this is time to pay the piper. Collect seed and scatter it over the patches you dug from. Or collect seed to grow in woodlands at home – without of course, taking too many away from a place they could grow naturally. See the article in Modern Farmer. The seeds scattered in zones 3-7 in early fall, take 6 to 18 months to germinate, and the plants take 5-7 years to grow to harvestable size. Thus it’s easy to see how wild ramps have been seriously over-harvested.

Buy seeds year-round and bulblets in late winter at rampfarm.com and mountaingardensherbs.com.

Read more in Growing and Marketing Ginseng, Goldenseal and Other Woodland Medicinals by W. Scott Person and Jeanine Davis of North Carolina.

Alliums for July: harvest minor alliums, finish harvesting bulb onions, snip and sort garlic and bulb onions.

Siberian garlic.
Photo by Southern Exposure Seed Exchange

Allium planting in July

In Virginia, July is not a big month for planting alliums. If you have perennial leeks or Egyptian onions you could if necessary divide clumps and replant them. But I would postpone doing this if I could and replant dry bulbs in August, or divide newly re-sprouting clumps in September.

Allium harvesting in July

In June I listed dates of our usual allium harvests for that month. Some of the minor allium crops (shallots, leaves of perennial alliums) can be harvested in July, but some, like the tiny, purple shallot-like L’itoi perennial onion (Allium cepa var. aggregatum ) die back in June and are sending up new green shoots by early July, so you’ll have to wait for those to be big enough to harvest. During dormancy you could divide the clumps and replant. Harvests of full-sized bulb onions and cipollini (small bulb onions) continue through July.

Bulb onions

I discovered our bulb onion (A. cepa var. cepa) harvest dates had ranged more widely than the 6/15-6/30 I reported last month. In the years 2008-2012, we harvested bulb onions 6/4–7/26, depending on the variety and the weather. In October I’ll write more about choosing onion varieties for your area.

Bulb onions curing on a rack.
Photo Wren Vile

Curing bulb onions

Some books recommend curing in the outdoor sun. These books are written further north or further south! This doesn’t work in our climate, where we need to provide partial shade, moderate temperatures, and good air flow (and no rain). Further north, temperatures are lower, and onions do not bake during outdoor curing. Further south (in Georgia for instance) onions mature much earlier in the year (they have been growing over the winter). The sun is not yet too intense or the humidity too high, and they can cure onions in the field there.

Handle onions gently – many rots are the result of poor handling post-harvest. Spread in a single layer in a warm dry place, and check every few days. The ideal conditions are 85ºF-90ºF (27ºC-32ºC) with constant air movement, no direct strong sunlight. We use racks in a barn, with fans to keep the air moving.

Trimming, sorting & storing bulb onions

Trimming should begin about two weeks after you hung the onions to cure. Test them by feeling maybe a dozen necks to see if they are ready. Pinch the necks gently just above the bulb, and then rub your thumb and forefinger together. They are ready for trimming if the majority of the necks feel dry and papery. The necks should not feel slippery or moist. If more than one or two still feel damp, but not slippery, wait a couple of days before testing again. Do not wait more than three weeks after harvest to get the onions in storage. The longer you leave the onions hanging, the more rot you will have to deal with.

To trim get a good pair of scissors, and a glove on your scissor hand to prevent blisters. Trim the necks off about ½” (1 cm) from the bulb, and trim all the roots off.

When trimming, sort the onions into three categories. Onions with wet necks or soft spots are for immediate use at home. Bulbs that feel firm and have dry necks are storage bulbs, and should be trimmed and put into mesh bags, which we store lying flat on shelves in our basement. Most onions store reasona­bly well if spread in a layer less than 4″ deep or hung from the ceiling in small mesh bags. Avoid large bags where the weight of the onions will crush the ones at the bottom. Ensure good air circulation.

The third category is for bulbs that aren’t obviously use first, but for some reason might not store for months. Maybe the necks have a spongy feeling, or the skin is split, or the necks slip a little bit. Label these onions “Use Soon,” trim them into mesh bags and put them in the basement like the storage onions.

Onions can be stored at 60ºF-90°F (16ºC-32°C) if they have never been refrigerated. It is important to avoid the 45ºF-55°F (7ºC-13°C) range, because that’s when they sprout. We have limited refrigerated storage, so we keep alliums in the warmer storage range until room temperatures drop into the danger zone, by which time there is space in the cooler. More about onion storage in August.

Onion harvest
Photo by Raddysh Acorn

Here’s information from the Roxbury Farm Harvest Manual (upstate New York) – a quite different story from Virginia:

Storage onions

Pull the onions out of the ground, clean off some damaged leaf parts, taking care not to remove too many of the outer layers. Cut off the tops immediately, 2-4″ (5-10 cm) above the crown.  If for long-term storage, bring the onions to the greenhouse for curing. Cover the greenhouse with 80% shade cloth to protect onions from sunscald.

As soon as the necks are sufficiently dried up (you can no longer roll any stems between your fingers and the stem tissue feels like paper), and the leaves easily crumble off, give them a superficial cleaning, and move the onions into the barn (and not in the cooler due to high moisture levels). Store at 32ºF-41°F (0-5°C) 65-70% humidity.

Green bulb onions, harvest and cleaning

Pull the 3-4″ diameter onions out, before any leaves die, by grabbing the plants as low as possible on the stem to avoid crushing the green stems. Place the onions on the top of the bed all facing the same way. Clean off the outer leaves around the bulb to leave a clean white bulb. Bunch 2-4 onions together with twisties. Cut the excess length off the leaves so the bunch fits lengthwise in the box. Pick up the finished bunches, and place them in the box.

Washing onions would shorten their storage life. Remove most of the dirt in the field. Bunched fresh onions look much nicer when clean. Spray off the onions with a hose but do not dump them into a washing tub. Pack in closed containers for storage longer than a week. Store at 32-41°F (0-5°C), 95-100% humidity.

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Harvest minor alliums

Cipollini (A. cepa var. cepa) will be ready to harvest from spring transplants here in the first half of July, if they weren’t ready in late June. We sow those in plug flats 1/25 and transplant 3/21. Read more about cipollini in the June post. We love Red Marble, which stores really well. Purplette disappointed us – it doesn’t store well.

French Red shallots.
Photo Raddysh Acorn

Shallots (A. cepa var. aggregatum) grown from seed started in late January and transplanted in March will mature here 7/4 -7/30, 4-8 weeks later than those grown from replanted bulbs (planted in October). We started with a packet of seeds, replanting all we grew for several years. We got lots of winter-kill trying to over-winter the bulbs in the ground. To save bulbs for replanting in early spring, refrigerate them. And accept a later harvest than the 6/10 of fall-planted bulbs.

Top-setting onions (aka Egyptian onions, tree onions, walking onions) produce tiny red-purple bulbs in the umbel instead of flowers, maturing in September. They were previously named Allium cepa var. proliferum. According to Wikipedia, they are now known to be a hybrid of A. cepa and A. fistulosum. The larger bulbils can be harvested in July, and used to make mixed pickles.

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Other Allium tasks for July

Trimming garlic stems (blue nail polish optional!).
Photo by Brittany Lewis

Snipping, Sorting and Storing Garlic – see the link to my previous blogpost, where I spelled out these tasks, including setting up, snipping and sorting into three categories for replanting, for storing and for using soon. Garlic can be stored in the same high temperature range as bulb onions, provided it has never dropped into the sprouting temperature range of 40-55°F (5-13°C)

Sort potato onions – see the first step of this process described in my June post and the harvesting described in my May post. We made slatted racks 5′ by 2.5′ (150 x 75 cm) which stack on each other leaving space for air. Curing is important for quality and long-term storage. Space the bulbs loosely on the racks to provide good air circulation. If humidity is high, use fans, dehumidifiers or an air conditioned room, to improve drying. Curing takes 2 to 4 weeks.

I aim to sort through our potato onions once a month, starting a few weeks after harvest.

7/10-7/15: This could be the second sorting for fall-planted potato onions, the first sorting for late winter planted ones. Keep the clusters together, as breaking them apart stimulates sprouting. Wait till the third sorting, in early August, to snip off tops, separate the clusters, sort by size and decide how many to save for replanting. I’ll tell you about that next month.

Remove any rotting onions for immediate use or composting. Start sorting with the largest ones, in case you run out of time. Remove all that are bigger than 2″ (5 cm), bag, weigh, record and label. If you are on a fast track to increase your crop, refrigerate all the large onions at this time, carefully labeled so they don’t get eaten, to plant in September. Refrigerate or plant them, or eat them, the large ones won’t keep long.

Potato onions in early spring, after they have divided into a cluster.
Photo by Kathryn Simmons

Alliums for June: planting leeks, harvesting garlic and bulb onions

Dibbling holes for planting leeks.
Photo Wren Vile

This month is a big harvest time for alliums, and it’s also leek planting time in Virginia.

Transplanting leeks

We do this job in early June. I have written about leek planting in 2015 and in 2014 (from flats), and from a nursery seedbed in 2013 . Initially we liked the nursery seedbed method of growing transplants because it freed up space in our greenhouse and coldframes for the crops that really needed protection from the cold, which leeks really don’t. But leek seedlings are skinny, and easily lost to weeds, which we had a lot of in some beds. While planning to really clean up our act with the weed seed-banks in the beds (and plan to use only the cleanest bed for our leek nursery), we tried sowing in flats, and that’s the method we now use. We put the flats directly in the coldframes – we still save the greenhouse space. We found we got better seedling survival in the flats, so we didn’t need to plant as many as we did with the old method. We were able to cut back to 50% of what we had planted. Also the seedlings grew faster and we have been able to transplant 2-3 weeks earlier than with our outdoor seedbed method, from the same sowing dates.

Leek seedlings in flats in April.
Photo Pam Dawling

We also learned that weeding leeks is really, really important, and that it can be worthwhile to side-dress leeks part-way through their very long growing season. We made the mistake one year of letting weeds get big before we pulled them up (it was a wet year, not conducive to successful hoeing). We got miserable leeks that year, not just from the smothering effect of the weeds, but we now think that the weeds removed a lot of the soil fertility. We decided to plant fewer leeks and focus on taking better care of them! That has paid off.

Garlic harvest underway.
Photo Marilyn Rayne Squier

Allium harvests in June

We are still happily harvesting scallions (see Alliums for May)

Our June allium harvests have generally occurred in this order:

5/31–6/14 hardneck garlic,

6/10–6/25 Spring-planted potato onions. By “spring”, I mean Jan-late Feb here.

6/11–6/18 Softneck garlic

6/15–6/30 bulb onions. See the SESE Onion Growing Guide for more info:

“When most of the tops have fallen over, pull onions, cure in partial shade for 2-3 weeks until necks have thoroughly dried. Clip tops to within 1″ of the bulb. Breaking over the tops by hand to accelerate harvest harms the keeping quality of some varieties and helps the keeping quality of other varieties.”

Elephant garlic will also be ready in June, but we stopped growing it when so much winter-killed that we harvested less than we’d planted! Elephant garlic is botanically a leek (A. ampeloprasum var. ampeloprasum).

The small Cipollini bulbs (aka cocktail onions, boiling onions, pickling onions) may also mature this month. The larger ones can be used as fresh bunching onions. All may be cured. Some of those store well (Red Marble for instance). Others such as the flat Gold Coin do not at our latitude, as the necks don’t dry tight, so those should be used soon or pickled. Cipollini naturally have more sugar than most onions, which makes them ideal for caramelizing in butter or oil or roasting whole.

Hanging garlic in netting to cure.
Photo Nina Gentle

Harvesting garlic

As I noted last month, hot weather above 91°F (33°C) ends bulb growth and starts the drying down process. I wrote Garlic Harvest step by Step and Drying and Curing Garlic Step by Step here in 2016, along with some ponderings about whether a ground floor shed or an upstairs barn offers the better airflow, and whether better airflow is worth hauling all the garlic upstairs and down again. We didn’t come to a conclusion, but we didn’t find time to build our new barn. So once again, we are hauling the garlic upstairs to cure and down again after it’s trimmed and sorted next month.

Hopefully you will have removed any mulch when you got the scape-appearing signal, and the soil will have had a chance to dry to a workable level. We were doing quite well until we got 3.5″ of rain in one day. Now it’s all much wetter than ideal.

Hang your garlic to cure for 3-6 weeks or even longer, with fans if the humidity is high. Don’t set the fans too close to the garlic, your goal is to improve the air flow, not blast the bulbs and shrivel them up. I’ll come back to the question of how to tell when the garlic is cured and what to do then next month. If your garlic is ahead of ours, see my book Sustainable Market Farming, and know that the key is dry necks.

Garlic bulb cut horizontally to check maturity (good now or soon).
Photo Wren Vile

Signs of garlic maturity

If you live in a cooler climate than us, you might be puzzling over when to harvest your garlic. Margaret Roach in the Hudson Valley, New York, has a great article on determining garlic maturity on her blog A Way to Garden. Harvest there happens 7–8 weeks after ours. Margaret has a good collection of articles on growing, harvesting and curing garlic.

Watch the color of your garlic patch for a general “fading” and also count how many fully green inner leaves there are on a dozen random sample plants. Green leaves represent intact “wrappers” on the bulb, and having at least 4 will help your bulbs store well.  Six is better, five is enough, if your garlic doesn’t have to travel to distant markets. If you wait too long, the wrappers will rot in the soil.

Another sign of maturity that we use with our hardneck garlic is to dig a few sample bulbs, and cut them in half horizontally. If there are small air spaces open between the remains of the stem and the cloves, the bulbs are ready. If the cloves have not even differentiated, and you are viewing a single mass of garlic, you are too early by quite a bit. Test once a week. If your cloves are already springing apart from each other, you are late. Your delicious garlic will not store for long. You might need to mince and freeze it in ice cube trays, if you want to preserve some for a while.

Softneck garlic

We grow Polish White. Softneck garlics tend to store for longer than hardnecks, so we always save ours till we’ve eaten the hardneck garlic. The big reason we don’t grow only or mostly softneck garlic is that the bulbs have lots of tiny cloves in the center, and these are tedious to peel, when you are cooking for a hundred. According to Ira Wallace at Southern Exposure Seed Exchange, most hardnecks store 4-6 months, although Music and Chesnok Red can keep 7 months or more in central Virginia. Softnecks such as Italian Softneck, Inchelium Red and Silverskins can store for up to 12 months under good conditions. 

Potato onions.
Photo Southern Exposure Seed Exchange

Harvesting spring-planted potato onions

The harvesting process is the same as for fall-planted potato onions. Lift them gently when the tops have died down, and put them to cure on racks with fans. If any of your spring-planted bulbs have produced bulbs larger than 2.5″ (about 6 cm), go ahead and eat those, or refrigerate them till September and replant. Those giants do not store well.

Sorting potato onions

Potato onions need sorting about once a month to remove any that are rotting. If it is already a month since you harvested your fall-planted multipliers, do the first sorting now. Timely sorting will minimize waste, because you will stop rot spreading. And you might get to some that are still “good in parts”.

Onion bed in late April.
Photo Kathryn Simmons

Harvesting bulb onions

There are many different onion varieties and the ones for your area will depend on your latitude. I wrote about this in my book Sustainable Market Farming, and for now, I’ll skip that complex issue. I’ll come back to it in the fall. Assuming you have grown some bulb onions, it’s now time to harvest, as they mature.

If the varieties you grew are not storing types, simply pull them up when you want to eat them, or when the tops fall over. Most kinds will keep for a few weeks, but some not much longer than that. Be realistic! If you have lots of non-storing ones, you can sell, trade or give them away. Or you can chop and freeze them. Or use them in salsa.

The tops of the onions start flopping over here in mid- to late-June; this is the sign that they are ready to harvest. It’s best to harvest during drier weather, but sometimes you have to harvest wet just to get them out of the ground. Hot, wet weather is the worst, so it is best not to let the onions sit around in wet soil during very hot days.

Start to harvest a variety when about 50% or more of the tops have flopped over. Gently lift the onions out of the soil—harvest only the onions with floppy tops, leaving the upright onions in the ground to harvest another day. Harvest each bed twice—once to get just the floppy ones, and then the second time to get all the rest.

Storable varieties should be cured on racks for best airflow, until the necks are dry – about two weeks after hanging the onions. Rub the necks between finger and thumb to determine if they are dry and strawy, or still damp. Trim tops and roots of dry bulbs.

No matter what, do not wait more than three weeks after harvest to clear a rack and get the onions in storage. The longer you leave the onions to hang, the more rot you will have to deal with. After three weeks they start to get worse, not better.

Bulb onions curing on a rack.
Photo Wren Vile

Alliums for May: harvesting garlic scapes, scallions and fall-planted potato onions

Pickled garlic scapes, okra and beets.
Photo Bridget Aleshire

This is the first of a new monthly series of blog-posts on Alliums for the Month, which, like my previous series on lettuce and Asian greens, I plan to run for a year. Alliums are the onion family. With this series, I’m going to talk about which alliums to harvest each month, which to plant, and which need other kinds of attention.

Weeding alliums

I haven’t thought of any alliums to plant in May (at least, not here in central Virginia), but there’s plenty to harvest, and don’t forget to weed! Because alliums don’t have big spreading leaves, they are not good at shading out weeds, so we have to take care of the weeds for them! Particularly bulb onions and garlic this month, as they are only a few weeks away from harvest and will benefit from removing weeds and mulch to let in fresh air to help the bulbs dry down (rather than get fungal diseases!)

Harvesting garlic scapes

Starting any day now, we will begin harvesting garlic scapes (the firm, edible flower stems of hardneck garlic). My previous posts about scapes are some of my most popular ones.

Pulling garlic scapes.
Photo Wren Vile

See last year’s Garlic scapes, upcoming events, hoophouse seed crops, posted on May 2, 2017. There I noted that in 2017, scapes came early, as did Tulip Poplar flowers, at the end of April. We harvest scapes two or three times a week for about three weeks, until no more appear. Garlic scapes are one of the first outdoor crops of the year, apart from rhubarb and asparagus, and their flavor is refreshingly different from leafy greens (the staple hoophouse crops of early spring) and stored winter roots.

I posted Garlic scapes! Three weeks to bulb harvest on May 11, 2015. That year scapes were later than average. This post is a very popular one, and I’m still wondering if I was over-confident in predicting 3 weeks to bulb harvest everywhere in the US! Please do leave a comment if you have records for how long you get between scapes and garlic bulb harvest.

I’ve done some research into what triggers flowering in garlic, but haven’t found much solid info yet.  In general, plant flowering is triggered by some combination of enough vernalization (chilling hours during the winter and early spring – maybe 10 weeks below 40F), 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 plant hormones, produced by one or more genes in 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.

There is a bit more information about the triggers for bulb initiation and for drying down. Garlic bulb initiation (and the end of leaf growth) is triggered by daylight increasing above13 hours in length (April 10 here at 38°N). Soil temperatures over 60°F (15.5°C) and air temperatures above 68°F (20°C) are secondary triggers. When I was in Jamaica last May, I researched growing garlic in the tropics, and it may be that temperature is a bigger trigger and daylength is less important in tropical latitudes where daylength does not vary much. Certainly some growers had produced garlic when I didn’t expect it to be possible.

Hot weather above 91°F (33°C) ends bulb growth and starts the drying down process. I don’t yet know how many hours over that temperature the garlic needs before drying down is triggered. We had a few very hot days last week.

It is important to get plenty of good rapid growth before conditions prevent any more growth. Garlic can double in size in its last month of growth, and removing the scapes (the hard central stem) of hardneck garlic can increase the bulb size 25%.

In the 2015 post I described how we pull our garlic scapes, to get the most out–we love this crop! We also appreciate a late-morning task that’s done standing up! In that post I described the value of mulch and when to remove it.

Garlic scapes to cheer us up posted on May 10, 2013 has been reread a lot–whether that’s because readers love garlic scapes, or seek cheering up, I can’t say.

Pulling garlic scapes – the long view.
Photo Wren Vile

Our harvest process

Here’s the short version. Those looking for more detail can go to my 2015 post.

  1. When scapes arrive, plan some late morning or early afternoon time two or three times a week to harvest them.
  2. As soon as the pointed cap of the scape has emerged above the plant center, firmly grasp the stem just below the cap and pull slowly and steadily straight up. The scape pops as it leaves the plant and you have the whole length of the scape, including the tender lower part.
  3. Gather them into buckets, with the scapes upright, so they are easy to bunch or cut up.
  4. Put a little water in the bucket.
  5. They store well in a refrigerator for months if you don’t use them sooner.
  6. In a few days, more scapes will have grown tall enough to pull, and you can have a second chance on any that broke at your earlier attempt.

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Clumps of scallion transplants in a Speedling flat, ready to transplant earlier in spring.
Photo Pam Dawling

Harvesting scallions

In May our outdoor planted scallions start. For outdoors, we use transplants, started in January and February, and transplanted in March and April. We sow in Speedling plug flats, a small pinch of seed in each cell, and transplant the undivided clump/plug. We can get a lot of scallions in a small space. Around May 10, the first ones are big enough to harvest (just as the hoophouse ones finish up – what planning!)

To harvest, we loosen the soil with a digging fork, then lift out a clump. We shake the plants, keeping them in a cluster, and trim off the roots and the ragged tops. Holding the bunch in one hand, we pass the scallions one at a time to the other hand, pulling off a single outer leaf and giving the base of the plant a wipe with our spare hand. Next we set the scallions in a small bucket in water. When the bucket is full enough, we dunk the scallions up and down, and transfer them to a clean bucket with a small amount of water to keep them fresh.

Scallions planted in bunches, ready-to-harvest.
Photo Pam Dawling

It’s good to develop an efficient method with little scallions or the harvest takes way too long. Deal with scallions in bunches as much as possible (digging up, trimming), rather than one at a time. Pass them from hand to hand when cleaning rather than set them down on the ground and pick them up again one at a time. Set them into water so they are cleaning themselves while you work on the rest. Don’t fuss with them too much – pull off a single outer leaf, not more. Don’t pick at little bits of skin, unless quite gross. 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.

Roxbury Farm in New York State has a wonderful Harvest Manual. Page 45 on scallions says they harvest 50 bunches an hour, including trimming tops as needed, but not roots. They wash 100 bunches an hour on a bench, in bunches, with a power spray.

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A potato onion plant in early spring, showing the cluster that has developed.
Photo Kathryn Simmons

Harvesting fall-planted potato onions

Potato onions (Allium cepa var. aggregatum) are a type of hardy, perennial multiplier onion–once you have them you are self-sufficient. You don’t need to buy seed each year, but select the best bulbs from the ones you grew to replant for the next crop. Also known as Hill Onions, Mother Onions and Pregnant Onions, they produce a cluster of tasty (but not too pungent) bulbs from a single planted bulb, or a large bulb from a small one.

Potato onions have good drought resistance, pink root resistance, onion fly resistance and are widely adapted for different growing regions (not Florida or southern Texas). When properly planted they can withstand sub-freezing temperatures in every area of the continental U.S.

You can order potato onions from Southern Exposure Seed Exchange and other suppliers to be shipped in the fall. See SESE’s Perennial Onion Growing Guide and Garlic and Perennial Onion Growing Guide for growing information.

Yellow potato onions.
Photo Southern Exposure Seed Exchange

The potato onions which were planted earliest (September for us) will be ready to harvest first, at the end of May or early in June in our central Virginia climate. Once you see the tops start to fall over, stop watering the onions and let them dry down.

Potato onions are ready to harvest when the tops die. Not all will be ready the same day. Because onions easily get sunscald if left exposed after they are mature, it’s best to harvest the mature ones every few days. Don’t break over the tops in hopes of a single harvest–it really reduces the storage life. The potato onions sit on the surface and are easily picked up without tools. Handle them gently, to prevent bruising and scratching. Put them into crates or buckets, without pulling off any leaves.

The September planted potato onions were the largest bulbs when planted, and they will usually have divided and produced clusters of small onions. Do not break up the clusters as you harvest, because this triggers sprouting. Set the clusters in a barn or shed, on an airy bench or horizontal rack. The tops break easily, so you cannot hang them as you might hang garlic. Potato onions need good ventilation: we use box fans continuously.

If you find any bulbs larger than 2.5″ (about 6 cm), go ahead and eat those. The giants do not store well. Alternatively, refrigerate them till September and replant. The small and medium-sized bulbs keep 8-12 months under good conditions, and are the best to replant to grow more onions.

Potato onions need sorting about once a month to remove any that are rotting. We plant our large ones in September or early October, our medium-sized ones in late November and our small ones in late January. I’ll tell you more about those when the time comes.

Two beds of potato onions in spring, of different planting dates.
Photo Kathryn Simmons