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
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
- Sustainable wildcrafting of ramps, by North Carolina Extension Horticultural Specialist Jeanine M. Davis;
- Having Your Ramps and Eating Them Too by the “Johnny Appleseed of Ramps”
- Ramps, part 1: Wild Delicacies Under the Forest Floor By Bjorn Bergman
- Sustainable ramp harvesting Bjorn Bergman: only 5 to 10 percent of the ramps in a patch should be harvested each year to ensure their future survival
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.
Special Allium Topics for March: Sowing leeks, transplanting onions, harvesting garlic scallions, onion bolting factors
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.
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.
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 growth — vegetative, 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.