Hamilton College Community Farm

Plant: Onions

Family: Allium

Seed Varieties:
  • Yellow Cortland (F1) - Standard yellow storage variety. They grow uniformly and have a thick, hard skin for long storage.
  • Redwing - This is a standard red bulb storage variety, with a nice color in the rings, and a thick, hard skin.
  • White Spear (bunching/scallion variety) - Standard bunching onion with tall, upright blue-green leaves and bright white stems
Indoor Start Date and Cell Size:

Yellow Cortland - 3/10 and 3/14 in open 200s

Redwing - 3/28, 4/11 in open 200s

Bunching Onions - 3/10 in open 200s or 4 to 5 seeds per-cell in 50s; seed every two weeks until the end of April

Planting Tips:

It is critical to keep on top of watering in the greenhouse. If the onion seedlings dry out for even a few hours, the older leaves will die and growth will be tremendously set back.

Greenhouse Transplant Date and Cell Size:

Onions do not need to be transplanted in the greenhouse.

Outdoor Transplant Date and Bed Specifications:

Onions can withstand light frosts, but hold off on outdoor planting until plants are more mature (after 7-9 weeks in the greenhouse). Plant the seedlings 4 inches apart with four rows per bed. Plant bunching onions 1 to 2 inches (or 4 if they are planted in a clump from a 50 cell), again with four rows per bed. Row cover can be used the first month to speed growth.

Plant Needs:

Alliums do a poor job of shading out weeds and so attention must be paid particularly early on so that weeds do not encroach. Weeds stunt growth remarkably.

Cultivation Techniques:

To control weeds, cultivating by hand early on is the only option, particularly when the seedlings look so much like grass. As the plants mature, the blue ‘snake’ hand cultivator works well.

Pests and Pest Control:

Problems with pests have been minimal.

Harvest Techniques:

When they have reached a mature size, harvest onions by carefully pulling free from the earth by the leaves. Be careful not to rip the leaves from the onion. If the onion is not coming up easily, a trowel can be used to loosen it. When harvesting onions to sell fresh with the leaves still on, cut off the roots and clean of dirt as much as possible, but do not wash. Onions can also be harvested when they are approximately 1 inch diameter and dried and sold as baby onions by the pound. Harvest bunching onions in a bunch of approximately 10 when they reach 1⁄2 to 1cm diameter. In late summer or early fall, the leaves of the onions will begin to yellow and die back. When most have done so, harvest all the onions and allow to dry in a shaded location with good air circulation for several weeks. (The wire drying rack placed under the shed awning works well.) When completely dry, cut off roots and leaves, and remove any dirt and loose skin. The onions are now ready for sale as storage onions.


When fully cured, unbruised onions can be stored in a cool dry location and will keep for several months.


For retail, sell fresh onions at $1.50 a pair, baby onions at $2.00 per pound, bunching onions at $1.50 per bunch and dried onions at $1.50 per pound. Sell at $0.75 per pound for wholesale.