Garlic Planting and Freeing Trapped Shoots

Garlic planting crew.
Photo Valerie Renwick

Planting Garlic

We are planting garlic, a topic I’ve written much about! Here are links to a few of my Allium of the Month posts from 2018-2019 and my slideshow.

Sign up for the free Growing for Market newsletter  and read my article How and when to plant garlic this month. That article mentions Get ready for garlic planting which you can read if you are a Full Access Member. I wrote these articles back in 2012, so I do have some newer info in my slideshow and my blog posts from last year.

See last year’s Alliums for November for

How Much Garlic to Plant

Popping Garlic Cloves for Planting;

Pre-plant Seed Garlic Treatments to reduce pests and diseases.

Planting garlic cloves, using a 5″ (13 cm) measuring stick.
Photo Brittany Lewis

Preparation for Garlic Planting

Cloves for planting should be from large (but not giant) bulbs and be in good condition. Garlic for planting should be separated into cloves 0–7 days before planting. 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 convenient lever for separating the cloves. We sort as we go, putting good size cloves for planting in big buckets, damaged cloves in kitchen buckets, tiny cloves in tiny buckets and outer skins and reject cloves in compost buckets. Don’t worry if some skin comes off the cloves — they will still grow successfully. The tiny cloves get planted for garlic scallions (see below).

When to Plant Garlic

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).

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.  We plant in early-mid November. (We used to plant at the end of October or early November, but we’ve moved later.) 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.Instructions from Texas A&M say less than 85°F (29°C) at 2″ (5 cm) deep. In California, garlic can be planted in January or February.

Closing the furrows over the garlic cloves.
Photo Brittany Lewis

Mulch your Garlic Beds

After planting, pull soil over the cloves, tamp or roll to get the cloves in good soil contact to help the roots grow. Within a couple of days, mulch the beds. At planting time, the soil is still warm, and the newly separated cloves are now primed to start growing. If you want to roll out mulch as we do (big round bales of spoiled hay), then you need to act before fragile garlic shoots emerge from the soil. If you are using loose mulch you can blow or throw it over the beds, and a few emerged shoots are no big deal.

Garlic Scallions

Garlic scallions are small garlic plants, mostly leaves, the garlic equivalent of onion scallions (bunching onions, spring onions, escallions). Great for omelets, stir-fries, pesto, soups, and many other dishes. If you want to have Garlic Scallions to eat or sell in early spring, when new fresh vegetables are in short supply, and homesteaders may be running out of stored bulb onions, see my post Alliums for March.

You could plant these next to your main garlic patch, or in a part of the garden that’s easily accessible for harvest in spring. We plant our small cloves for scallions at one edge of the garden, and as we harvest, we use the weed-free area revealed to sow the lettuce seedlings for that week.

Planting garlic scallions is simplicity itself! Plant small cloves close together in closely-spaced furrows, simply dropping the cloves in almost shoulder to shoulder, any way up that they fall. (If you’ve just finished a large planting of main-crop garlic, you’ll probably be too tired to fuss with them anyway!) Close the furrow and mulch over the top with spoiled hay or straw.

November-planted garlic scallions in February.
Photo Pam Dawling

With a last frost date of 20–30 April, we harvest garlic scallions March 10 to April 30 in central Virginia, or even into May, if our supply lasts out, and we don’t need the space for something else. Harvesting is simple, although depending on your soil, you may need to loosen the plants with a fork rather than just pulling. Trim the roots, rinse, bundle, set in a small bucket with a little water, and you’re done!

Rather than dig up whole garlic scallion plants, some people cut the greens at 10″ (25 cm) tall and bunch them, allowing cuts to be made every two or three weeks. We tried this, but prefer to simply lift the whole plant once it reaches about 7″–8″ (18–20 cm). The leaves keep in better condition if still attached to the clove. Scallions can be sold in small bunches of three to six depending on size. A little goes a long way! If you do have more than you can sell in the spring, you could chop and dry them, or make pesto for sale later in the year.

Garlic scallions ready for harvest in early spring.
Photo Wren Vile

Cold-hardiness of Young Garlic Plants

  • At 12°F (−11°C): garlic tops that have grown fairly large will die
  • At 5°F (−15°C): garlic tops if still small will die.
  • When properly planted, cloves can withstand winter lows of –30°F (–35°C).
  • Garlic roots will grow whenever the ground isn’t frozen
  • Garlic tops will make growth whenever the temperature is above 40°F (4.5°C).

If the tops do get frozen back, do not despair! They will regrow. The growing point of alliums (garlic, onions and relatives) is close to the bulb, probably under mulch, certainly in or close to the soil, where temperatures are warmer. If your garlic gets frozen back twice, the yield will be less than if it had not got frozen, but we don’t control the weather. If your climate is getting colder in the garlic-planting season, plant deeper and/or earlier. But don’t plant earlier if climate change is giving you hotter fall weather!

Garlic shoots poking through the mulch in January.
Photo Pam Dawling

Free Trapped Garlic Shoots

See last year’s Alliums for December for my post  Free trapped garlic shoots.

Watch your mulched garlic beds and when the shoots start to emerge, choose the moment to free any trapped shoots, by working along the rows, investigating each spot where you expect a garlic plant to be, but nothing has emerged. Your goal is simply to let the shoot see the daylight. Then it will right itself. Don’t reveal any bare soil, as that will grow weeds (and let colder winter air at the garlic.) Don’t over-work this – as soon as any part of a shoot is visible, leave that plant alone, and move on to the thousands of others. It isn’t necessary to make all the leaves visible, or to clear around the whole plant.

Choosing the right time is tricky. I used to say when half or more of the shoots are visible, but one year we were having a crop disaster, and we waited too long – we were never going to have half visible. Usually, most of them emerge at the same time. it would be helpful to note down how many weeks after planting this is likely to be. We somehow haven’t done that – I think it’s about 3 weeks. Leave a comment if you have an answer!

 

Hoophouse Squash Variety Trial, Garlic Recap, Flowers for Organic IPM

Golden Glory Squash in our hoophouse in mid-June.
Photo Pam Dawling

Hoophouse Squash Variety Trial

A month ago I wrote about our hoophouse squash variety trials for pollination issues and blossom end rot. I think our problem was mostly unpollinated squash, rather than blossom end rot. Go to last month’s post for valuable links to distinguish the two conditions.

We planted 15 Golden Glory zucchini (good at setting fruit without pollinators) along with 25 Gentry yellow squash (a favorite variety, except that we had pollination troubles with it in our hoophouse for several years). The trial is almost over, we’re about to pull those plants, and we have plenty of squash coming in from our outdoor plantings now. The first outdoor planting includes some Golden Glory too, so if I have more news I write about it when it happens.

Gentry yellow squash in our hoophouse in mid-June
photo Pam Dawling

As I said last time, I recorded the number of small rotting squash we removed. The Golden Glory produced far fewer rotten unpollinated fruit.

Date 15 Golden Glory plants: rotted fruit Golden Glory: rotted fruit per plant 25 Gentry plants:

rotted fruit

Gentry:

rotted fruit per plant

5/13 2 0.13 12 0.48
5/14 2 0.13 5 0.2
5/17 0 0 32 1.28
5/21 15 1 54 2.16
5/27 9 0.6 39 1.56
6/4 13 0.9 29 1.2
6/10 2 0.13 11 0.46
6/14 2 0.13 9 0.43
Average per plant   0.38   0.97

 But low numbers of rotted fruits is not the only goal! Yield is important too, and the healthiness of the plants (which relates to yield).

We noticed that the plants were starting to die, and we thought of bacterial wilt. But when I tried the test for that disease, the results were negative. The test is to cut through the plant stem, rub the cut ends together, then slowly separate them. If the plant has bacterial wilt, there will be bacterial slime in strings between the stem ends when you slowly draw them apart. We got nothing like that. More research needed!

We pulled the dying squash, put them in a black trash bag and set that in the sun to cook.

Diseased squash, mid-June.
Photo Pam Dawling

Here’s what we found:

Date 15 Golden Glory plants: Number of healthy plants Golden Glory: Percentage of plants healthy 25 Gentry plants:

Number of healthy plants

Gentry:

Percentage of plants healthy

6/4 15 100% 25 100%
6/10 15 100% 24 96%
6/14 15 100% 21 84%
6/18 10 67% 20 80%
6/24 6 40% 18 72%

Initially, the Gentry started to keel over, then suddenly the Golden Glorys weren’t so glorious!

As far as yield, we did not measure it much. We only have notes from one day, 6/10. We harvested 7 squash from 15 Golden Glory plants (47%) and 14 Gentry from 24 plants (60%). Different people harvested on different days, meaning sometimes they were picked bigger than on other days. My sense is that the Golden Glory were not as productive throughout their harvest period. They are beautiful, the plants are open, easier to harvest from, and we had fewer rotten squash, and initially fewer dying plants. Is this enough to recommend them for an early hoophouse crop in future years?

My inclination is to also try another variety that is rated well for setting fruit without pollinators (hence fewer tiny rotting squash) and try harder to also record yield as well as problems next year!

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Garlic Recap

Our garlic is at the “Trim and Sort” stage, but depending where you garden, yours may be at a completely different stage. See my blogposts from the previous year, when I posted my Alliums for the Month Series.

Trimming garlic stems.
Photo by Brittany Lewis

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For people in colder climates than Virginia, you may be just starting to harvest your garlic. Learn from Margaret Roach (who grows in Massachusetts) in A Way to Garden

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Here are a couple of allium resources that didn’t make it into the Alliums for the Month Series

Mulching alliums

The Nordells on mulching alliums

RAMPS

Barry Glick sells ramps

“The Cat Is Out Of The Bag”!!!
Sunshine Farm & Gardens
696 Glicks Road
Renick WV 24966 USA

Ramps plants.
Photo Sunshine Farm and Gardens

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Flowers for Organic IPM

This is my post on the Mother Earth News Organic Gardening Blog

Organic Integrated Pest Management involves tackling pest problems one step at a time with ecologically-based practices, starting with reducing the chances of the pest ever getting a grip on your crops. Follow prevention with avoidance, and finish with pest-killing if needed. I recommend the ATTRA online publication Organic Integrated Pest Management. Each  page is a poster, complete with good photos and concise clear info.

In May we transplant flowers in our vegetable garden to attract pollinators and pest predators. We like a combination of sunflowers, dill, borage, cosmos, calendula, tithonia (Mexican sunflowers), zinnias. See my earlier Mother Earth News post Insectaries: Grow Flowers to Attract Beneficial Insects

We sow sunflowers about every 10ft (3 m) in each of our bean beds. We are growing sesame surrounded by French marigolds in our hoophouse to deter nematodes, which we have in parts of our hoophouse soil. Sesame is apparently particularly good in deterring root knot nematodes, the type we have.

French marigolds and sesame to deter Root Knot nematodes in our hoophouse.
Photo Pam Dawling

Alliums for March: transplant bulb onions, harvest garlic scallions, ramps, minimize onion bolting

Flats of March-sown leek seedlings in our coldframe in early April.
Photo Pam Dawling

Allium Planting in March

  • Divide and replant Egyptian onions and perennial leeks, during March or April
  • Sow leeks in flats, coldframes, or raised beds. See below
  • Transplant fall-sown bulb onions early in the month. see Alliums for November and February. More info below
  • Transplant cipollini seedlings. Cipollini, also known as pearl or boiling onions, are varieties of short day onions sown in spring, planted at high density, which form small bulbs and mature in a couple of months.
  • Plant shallots Jan-Feb.
  • Plant softneck garlic cloves or bulbs for garlic scallions. See Alliums for February
Garlic scallions ready for harvest.
Photo Wren Vile

Allium Harvests in March

  • Start harvesting garlic scallions (3/10 to 4/30 in central Virginia). See below for more details
  • Harvest hoophouse scallions (our 10/20 sowing Feb 20- mid-Mar and our 11/18 sowing from mid-March.)
  • Harvest leaves of Egyptian onions & perennial leeks, Sept- April
  • Harvest winter leeks Dec- March. See Alliums for January and Alliums for November
  • Harvest ramps, sustainably for one month, from when tree buds appear (late March or early April in the Appalachians). Ramps are a spring ephemeral of deciduous forests. By late May, the leaves die back and a flower stem emerges. Wild ramps are being over-harvested, and it is important to make sure that not all these wild culinary delights vanish and they are still able to find their way onto plates in a sustainable fashion. See
Harvested ramps.
Photo Small Farm Central

Alliums to Eat from Storage in March

  • Eat softneck garlic from storage once all the hardneck has been used (softneck stores longer)
  • Eat bulb onions from storage, including bulbils from Egyptian onions if you stored those.

Alliums to Weed in March

All overwintered alliums will need weeding in March and once a month after that until harvest. Mulched crops can be weeded during wet weather, if necessary, and the pulled weeds can be discarded on top of the mulch, where they stand a much better chance of dying then weeds discarded on bare soil! It is helpful to have a list of tasks that can be done when the soil is wet, in case of a wet spring (or any season really). Perennial crops and annuals with mulch are the main jobs for this list (along with tool repair and sharpening).

Newly planted alliums in bare soil will benefit from hoeing during dry weather before the weeds get very big at all. Hoe every 1-4 weeks as needed until harvest. Because of their vertical tubular or strap-like leaves, alliums do not compete well with broadleaf weeds and can easily become stunted in high weeds. We learned the hard way one year when our leek beds grew very big weeds. Even though we did pull the weeds, the leeks never grew very big. As well as the competition for light, we think our huge weeds pulled too many nutrients from the soil. After that, we acknowledged the wisdom of growing fewer leeks and taking care of them better, rather than over-extending ourselves.

A fine bed of onions in spring.
Photo Kathryn Simmons

Special Allium Topics for March: Sowing leeks, transplanting onions, harvesting garlic scallions, onion bolting factors

Sowing leeks

Calculate how many leeks of each variety you want to harvest, add a margin. Each of our 90 ft (27.5 m) raised beds takes 4 rows of leeks, with plants 6″ (15 cm) apart. That’s 720 plants per bed. We sow in 24″ (60 cm) long flats, aiming for 3 seeds per inch (<1 cm apart). With 6 rows per flat, we need 1.67 flats/bed with no extras. We’ll call that 2 flats per bed.

We don’t need heat to start the leek seedlings, only time, so we put the flats directly into the coldframe. The minimum temperature for leek germination is 35F (), the optimum 65-85F () and they take 8-16 days just to germinate, even at the ideal temperature. Alliums are so slow! I always allow at least 10 days.

Leeks take 10-12 weeks to grow to transplant size. We sow ours March 21 for June 1 transplanting, which is only 10 weeks. When we grew them in a raised bed, it took 12 weeks. We like Lincoln and King Richard for leeks to eat in October and November and Tadorna for over-wintering, to eat December-February.

Transplanting onions

Transplant fall-sown onions as early in spring as possible, and those sown after New Year once they have at least three leaves (four or five is better). The final bulb size is affected by the size of the transplant as well as the maturity date of that variety. The ideal transplant is slightly slimmer than a pencil, but bigger than a pencil lead. Onion seedlings are slow-growing: even in spring they can take ten weeks to reach a size suitable for transplanting. Overly large transplants are more likely to bolt. If seedlings are becoming thicker than a pencil before you can set them out, undercut two inches (5 cm) below the surface to reduce the growth rate. Or use them as scallions.

Some books recommend trimming the tops at transplanting time, but I used to avoid this because I believed it reduces the yield. I forced myself to test out this idea one year, and found I got the same yield from trimmed and untrimmed onions. Trimmed ones are easier to plant. Transplant 4″ (10 cm) apart for single seedlings or 12″ (30 cm) for clumps of three or four (not more than four). Set plants with the base (stem plate) 1/2″–1″ (1.3–2.5 cm) below the soil surface. Some books recommend as deep as two inches (5 cm). Don’t plant too shallowly. Give plenty of water to the young transplants: keep the top 3″–4″ (8–10 cm) of the soil damp for the first few weeks to prevent the stem plate from drying out.

Onion bed in late April.
Photo Kathryn Simmons

Harvesting garlic scallions

With a last frost date of 20–30 April, we harvest garlic scallions from early March until May, if our supply lasts out, and we don’t need the space for something else. Harvesting is simple, although depending on your soil, you may need to loosen the plants with a fork rather than just pulling. Trim the roots, rinse, bundle, set in a small bucket with a little water, and you’re done!

Some people cut the greens at 10″ (25 cm) tall and bunch them, allowing cuts to be made every two or three weeks. We tried this, but prefer to simply lift the whole plant once it reaches about 7″–8″ (18–20 cm). The leaves keep in better condition if still attached to the clove. Scallions can be sold in small bunches of three to six depending on size. If you do have more than you can sell in the spring, you could chop and dry them, or make pesto for sale later in the year.

Onion bolting factors

Onions are cool-season plants. They have three distinct phases of growthvegetative, bulbing and blooming (bolting), and the switch from one phase to the next is triggered by environmental factors. It does not work to plant onions at a random date in the year without taking account of these environmental factors. Success depends on understanding what this crop needs during each of the three phases. To get a full understanding of the three phases and the factors that cause plants to switch to the next phase, see the Bulb Onions chapter of my book, Sustainable Market Farming.

Continue reading “Alliums for March: transplant bulb onions, harvest garlic scallions, ramps, minimize onion bolting”

Sequential Planting slideshow, seedlings and garlic scallions

Here’s one of the slideshows form my three workshops at the PASA Conference last weekend. I’ll add the others over the next few weeks. To see all my slideshows, see the Slideshows category in the sidebar of this page, or go to the link at SlideShare.net

Meanwhile at home, we’ve been starting seedlings. We have a plastic tent with a heat mat for the tomato and peppers plants destined for the hoophouse.

Our heat mat and tent for tender seedlings in our greenhouse.
Photo Pam Dawling
February photo of tomato and pepper seedlings with heat mat and plastic tent.
Photo Pam Dawling

The hardier seedlings are in the greenhouse without any other protection, except for a back-up heater set to 45F, and rowcover at night if it gets exceptionally cold..

Open flats of brassica seedlings. The nearer flat is a 3″ deep seed flat with four rows of seedlings. The back ones are transplant flats with 40 bigger seedlings spotted out.
Photo Pam Dawling

And outdoors the ground is saturated, with standing water. Not much gardening is happening! But our garlic scallions are growing just fine.

Our garlic scallions in February. we usually space the rows much closer than this. We’ll start harvesting when they reach 7″ in height.
Photo Pam Dawling

Alliums for February: garlic scallions, digging leeks from frozen soil

September-planted (left) and November-planted (right) beds of potato onions in April.
Photo Kathryn Simmons
  • Plant small potato onions (less than 1.5″ (4 cm) diameter) in early Feb, if not Jan. See Alliums for January
  • Sow shallot seed. See Alliums for January
  • Sow scallions for transplant See Alliums for January
  • Transplant fall-sown bulb onions late in the month. see Alliums for November
  • Plant shallot bulbs Jan-Feb. See Alliums for January
  • Plant soft neck garlic cloves or bulbs for garlic scallions. See Alliums for November and learn a new trick. Some growers are finding they can get a better income from garlic scallions than from bulb garlic, and so they are working to extend the garlic scallion season. We have only ever planted small cloves for garlic scallions in early November immediately after planting our maincrop garlic. By planting later it is possible to stretch the harvest period out later. Softneck garlic varieties can make worthwhile growth for scallions even if planted after the start of January. Some growers have experimented with replanting small bulbs of garlic, not even dividing the bulbs into separate cloves. This could be a good way to salvage value from a poorly-sized garlic harvest.

Allium Harvests in February

An October 20 sowing of scallions in the hoophouse in January. Maybe they’ll be ready mid-February?
Photo Pam Dawling
  • Harvest the last hoophouse scallions 9/6 at the beginning of Feb; harvest the 10/20 sowing later in Feb (and the 11/18 sowing from mid-March.)
  • Harvest perennial leeks as leeks (see Jan or Dec) Sept-Feb last month. See Alliums for December
  • Harvest leaves of Egyptian onions & perennial leeks, Sept- April
  • Harvest winter leeks Dec- March. See Alliums for January and Alliums for November
A colorful salad of rainbow chard, onion scallions and garlic scallions.
Photo (and salad) by Bridget Aleshire.

Special Allium Topic for February:: Harvesting Leeks from Frozen Soil.

When the soil is frozen there are two risks with trying to pry leeks out of the ground. One is breaking the frozen leek. The other is breaking your digging fork. If you only need a few leeks, there is a less risky method. (It’s still less risky for larger quantities, but also less practical.) Gather your digging fork, trimming knife and a container for the liberated leeks. Boil a kettle or two of water and pour the water on the soil around the leeks. If you still can’t dig the leeks up, go boil more water. If two trips with boiling water doesn’t work, I’d give up at that point! Obviously this isn’t going to work in climates with solidly frozen ground, until warmer weather arrives. But at some point it will get warm enough to use this trick and enjoy the leeks you’ve been craving.

This long view of our winter leeks was taken in December.
Photo Pam Dawling

Alliums to Eat from Storage in February

  • Eat softneck garlic from storage once all the hardneck has been used (softneck stores longer)
  • Eat bulb onions from storage, including bulbils from Egyptian onions if you stored those. Read more about garlic and onion storage in the Alliums for September 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

Garlic and Onions drying.
Photo Southern Exposure Seed Excahnge

Alliums for January: sow scallions, cipollini, shallots

Clumps of scallion transplants in a plug flat, ready to transplant.
Photo Pam Dawling

Plant scallions, shallots, cipollini mini-onions, small potato onions

In January, one of the first crops we sow is scallions for transplant. We sow in 200-cell plug flats, on January 17, aiming to get 4-6 seeds per cell. It takes 4 gm of seed for 200 cells. We transplant these clumps on March 21, with 3″ (7 cm) space between plugs. We need about 50 row feet (15 m) This grows us scallions already in bunches, and makes excellent use of the space. We make a second sowing of the same size on February 17 and transplant April 14. We also grow scallions in the hoophouse in winter.

French Red Shallot bulbs. Photo Raddysh Acorn

 Plant shallot bulbs January-February, if you haven’t done so before the winter.

Between late January and mid-February, sow shallot seeds. Transplant in late March. Shallots from seed will be ready for harvest 7/4-7/30, about a month later than harvests from replanted bulbs.

Cipollini, Mini-onions, Pickling Onions

Like bulb onions and scallions, cipollini are a biennial crop grown as an annual (A. cepa var. cepa). They are small bulb onions used whole for kebabs, pickles, casseroles, and stews. Depending on your latitude and the variety’s adaptation, these will provide bulbs from the size of large cherries to ping-pong balls. They tend to dry down nicely and store well. White varieties get sunburn here. Red Marble is good, stores well. Purplette doesn’t store well.

Mini-onions are viewed as a gourmet item, so the prices you can get may justify giving them greenhouse bench space, or even growing space in a hoophouse. We can grow these outdoors from seed sown 1/17-1/25, transplanting 3/10-3/21, leading to harvest 7/1-7/17.

Red Marble cipollini.
Photo Fedco Seeds

Small potato onions

In late January, plant small potato onions (smaller than 1.5″/4 cm) late January as soon as the ground can be worked. Or early February, if January is not possible. See Alliums for December for planting medium-sized bulbs, Alliums for September for information on planting the large ones. In order to make January planting possible, we prepare the bed for the small potato onions in the late fall and cover it with mulch for the winter. In late January or early February, we remove the mulch, make 4 deep furrows, plant the small onions (<1½”, 4 cm) on 4″ (10 cm) centers, cover with ½”-1″ (1-3 cm) soil, tamp down, and replace 4″-8″ (10-20 cm) of mulch. Label and write down how much seed was used. Eat any leftovers or give them to a friend. For 360′ (111 m) at 4″ (10 cm), we need 1080 bulbs plus 20% spare. (Approx 1300 bulbs). 425 bulbs = 18-20lbs (8-9 kg), 1lb (500 gm) =20-33 bulbs.

Harvesting and Eating

Eat onions and garlic from storage, including bulbils from Egyptian onions if you stored those.

You can enjoy eating Perennial leeks as leeks, September to February. See Alliums for December

If still green and visible, you can eat leaves of Egyptian onions and perennial leeks, September to April.

This is the time to enjoy winter leeks. We try to grow enough to supply 1 bed (720 leeks) each month, December to February

Other Allium Tasks

How to harvest and trim leeks.

Use a sturdy digging fork to harvest leeks.
Photo Pam Dawling

Be sure to get the prongs/times of the fork downwards into the soil, not at an angle that will stab the leek. Step on the fork and go deep enough to dislodge the leek when you lever back on the fork.

Trim the leek roots off with a big knife.
Photo Pam Dawling

After removing the roots, hold the leek upside down and slash diagonally at the leaves. This will remove the damaged parts of the tougher outer leaves and leave the tender inner leaves to eat.

A trimmed leek showing how the inner leaves are left longer than the outer ones.
Photo Pam Dawling

If you haven’t done it already, free trapped garlic shoots. Look for garlic shoots at whatever spacing you used.

Young garlic shoots which emerged through the mulch on their own.
Photo Pam Dawling
A trapped garlic shoot that was freed with human intervention.
Photo Pam Dawling

If you don’t see a garlic shoot where there should be one, part the mulch just enough to let the pale shoot see the light. Don’t leave any soil bare, it only leads to weeds!

Unusual Alliums List. (There are others)

While you are perusing seed catalogs, look out for these less common alliums, and consider if they have a place in your garden. The Clove Garden has lots of info on all types of onion. The Backyard Larder: Ali’s Alliums is also a good read.

  1. Pearl onions (Allium ampeloprasum sectivum), also known as button or baby onions in the UK, or creamers in the US, are a close relative of leeks, with thin skins and a mild, sweet flavor. They grow up to 1′ (2.5 cm) in diameter. They are especially popular in the Netherlands and Germany. Unlike bulb onions, they do not have layers of storage leaves but only a single storage leaf, like the non-layered cloves of garlic. The onions are ready to harvest 90 days from sowing. They are mostly used for pickling. Most onions grown for pickling today are simply small crowded bulb onions, with layers. Also see the Useful Temperate Plants Site  and How to grow Pearl Onions by Jenny Harrington
  2. Perennial Rakkyo (aka as true pearl onions, Japanese scallions, Vietnamese leeks) are Allium Chinense. These small onion bulbs are generally pickled.
  3. Canada onion (aka Wild onion) (Allium canadense) is a perennial sounding very like what we call onion grass or wild garlic in Virginia, although that is Allium vineale (crow garlic). The leaves of onion grass are hollow and round, while those of Canada onion are more flat and ‘solid’.
  4. Kurrat ( kurrat), is a Middle-Eastern cultivated leek, used mainly for the greens, which may be cut from the plant repeatedly.
  5. Field garlic Allium oleraceum is native to most of Europe, where it is a wild perennial, growing tall leaves (the part that is used).
  6. Ramsons Allium ursinum, buckrams, wild garlic, broad-leaved garlic, wood garlic, bear leek, or bear’s garlic, common in Europe. Looks like Ramps, (Allium tricoccum) but is not the same. The broad flat leaves are the part used.
  7. Japanese bunching onion and Welsh onion (native to Siberia or China, not Wales) are Allium fistulosum. They are sometimes used as scallions, as are some A. cepa. 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 which is eaten.

Alliums for December: Free trapped garlic shoots, divide perennial leeks

Sorry for the delayed post. We lost our internet in the storm 5 days ago. Just got it back. Ah rural life!

Perennial leeks (small ones)

Planting Alliums in December

Sow backup bulb onions 12/5 in the hoophouse, see Alliums for November. These will be transplanted outdoors March 1st or as soon after that as feasible. If this sowing is not needed for transplants, they can be used as scallions. Regular bulb onions are a biennial crop grown as an annual (Allium cepa var. cepa)

Divide clumps of perennial leeks and replant (see Special Topic below)

Egyptian onions, aka Top-setting onions, tree onions, walking 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. Divide clumps in Spring (March, April) and fall (late September to November, depending on your climate)

Further south, warmer than zone 7, plant garlic and elephant garlic. Elephant garlic is botanically a leek (A. ampeloprasum var. ampeloprasum).

Yellow Potato Onions.
Photo Southern Exposure Seed Exchange

Potato onions and shallots (which develop in the ground) are Allium cepa var. aggregatum. Plant medium-sized (1½”-2″, 4-5 cm) potato onions in late November-early December in zone 7. See Alliums for September on planting the large ones. Save the small ones to plant in January, as they won’t survive the winter well in the ground. On the plus side, the small ones store really well indoors, unlike the large ones.

  • For 360′ (110 m) @ 6″ (15cm) you need 720 bulbs plus 20% spare. Approximately 940 bulbs. 150 medium bulbs weigh about 20-21# (9 kg). 1# = 8 bulbs
  • Plant them at 6″ (15cm). If there are not enough medium-sized onions available, increase spacing or fill out with small onions.
  • Cover with ½-1″ (1-2 cm) soil, and add 4″-8″ (10-20 cm) mulch.
  • Store any leftovers till January, when the small ones get planted, if you want more.
A yellow potato onion plant in spring, showing how a cluster of onions forms.
Photo Kathryn Simmons

Here’s more information about Potato onions and shallots from Southern Exposure Seed Exchange:

The potato onion is closely related to the shallot. Like the walking onion they aren’t largely referenced until the 1790s when they gain popularity in English and American gardens. Shallots on the other hand, have been recorded in use for centuries and date back to Roman times. Southern Exposure’s yellow potato onion variety is an heirloom that dates back to prior to 1790. Both the potato and walking onions saw widespread use in colonial America. They were often easy to grow in conditions that were less than ideal and easy to keep year after year. Sadly these perennial onions fell out of favor during the 20th century. People chose to grow more seed onions as onion seeds and sets became more widely available.

Benefits of potato onions and shallots

  • They are not as readily bothered by the onion fly as are seed onions.
  • Once you have enough potato onions or shallots you need not buy seeds or sets again.
  • Some types of multiplier onions are in demand as gourmet items in restaurants.
  • Potato onions and many shallots store well, and can withstand subfreezing temperatures in every area of the continental U.S. when properly planted.
  • Perennial onions may be easier for you to grow. While some gardeners find seed onions to be an easy, productive crop others struggle with them. If you’re having a hard time with seed onions perennial onions are worth a shot.”

Harvesting alliums in December

Winter leeks, 12/8-3/1. Common leeks are Allium ampeloprasum var. porrum.

Scallions in the hoophouse at the end of November.
Photo Pam Dawling

Hoophouse scallions, (spring onions, escallions or salad onions). Like bulb onions, these are A. cepa var. cepa. Early Lisbon and Evergreen Hardy White scallion varieties are hardy to 0°F (−18°C), as are chives, garlic, a few leeks (Alaska, Durabel), some bulb onions, and yellow potato onions.

Perennial leeks as leeks (see Special Topic below).

Leaves of Egyptian onions and perennial leeks: Cut and use these September to April, as long as they are still green and in good shape.

Other Allium tasks for December

Garlic shoots emerging through the mulch.

Free trapped garlic shoots. Watch your mulched garlic beds and when the shoots start to emerge, choose the moment to free any trapped shoots, by working along the rows, investigating each spot where you expect a garlic plant to be, but see nothing. Your goal is simply to let the shoot see the daylight. Then it will right itself. Don’t reveal any bare soil, as that will grow weeds (and let colder winter air at the garlic.) Don’t over-work this – as soon as any part of a shoot is visible, leave that plant alone, and move on to the thousands of others. It isn’t necessary to make all the leaves visible, or to clear around the whole plant.

Choosing the right time might be tricky. I used to say when half or more of the shoots are visible, but one year we were having a crop disaster, and we waited too long – we were never going to have half visible. Usually, most of them emerge at the same time.

When properly planted and mulched, garlic can withstand winter lows of -30°F (-35°C). garlic roots will grow whenever the ground isn’t frozen, and the tops will grow whenever the temperature is above 40°F (4.5°C). If garlic gets frozen back to the ground, it can regrow and be fine.

Eat onions and garlic from storage, and if you harvested little bulbils from Egyptian onions in September, you can use them during the winter. They store well.

Cured garlic and onions hanging from a beam.
Photo Southern Exposure Seed Exchange

Special topic for December: Perennial Leeks (Allium ampeloprasum)

Divide clumps of perennial leeks and replant in late September to November and March-April. Harvest the larger leeks September to February, replant the rest. Ira Wallace of Southern Exposure Seed Exchange says:

“If divided and left to grow for 9-12 months, perennial leeks really make decent-sized leeks you harvest in October [or so]. This gives you something more like the early traditional leeks plus an assortment of smaller leeks to divide and let grow. [If you are] starting with only a few it’s best to just divide and grow larger for at least a year to get up to a decent quantity and size.”

In June, July and early August some people use larger bulbils in mixed pickles.

Perennial leeks will be dry bulbs in August and can be re-spaced between August and November into a larger planting for next year.

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.