Walla Walla Yellow Summer Onion

This item will drop-ship via USPS directly from our supplier according to your planting zone (please see below). If you would like to request a different shipping week than the one recommended for your zone, you can do that at checkout.

Onion Plants

Allium cepa Onion plants are drop-shipped by Priority Mail directly from our Texas supplier, so shipments can arrive from January through April according to your planting zone (see chart). You may also request a shipping week when placing your order.

Onions are dug as live plants from the field; shipping schedule may change due to weather conditions or other variables. You will be notified via email when your order has shipped.

Onion plant ship dates

When Your Onion Plants Arrive

Remove plants from the box immediately! They may seem a little peaked from travel, but don’t fret! Plant them in the ground as soon as possible, watering well. If you can’t plant immediately, unbundle the plants and heel them into some moist potting medium in a seedling tray, or wrap the roots in damp paper towels and wrap loosely in plastic. After planting, keep onion plants well watered and well weeded, and you’ll be rewarded!

Planting instructions (for conventional growing) will arrive with your shipment. As always, a professional soil test should guide your fertilization program. Onions are particularly sensitive to deficiencies in calcium and sulfur, and require steady nitrogen availability through the season. Band a balanced slow-release fertilizer like soybean meal or NutriVeg into your planting row at 2 lbs per 100 row feet, or a couple teaspoons per transplant hole. Water seedlings in well with fish hydrolysate with kelp (diluted at 2 oz per gallon water). Repeat the fish/kelp fertigation or side-dress with a readily available N source like blood meal several times throughout the season.

Onions

All the varieties we list are suitable for northern growers. If you live farther south, note our latitude specifications at the end of each description.

• Long-day: Must be north of 36° latitude, though some long-day types perform best north of 40°. These onions need 14-16 hours of sun a day to trigger bulb formation. May not perform well in continually hot soil temps.
• Intermediate-day: Also called day-neutral onions, generally need 12-15 hours of daylight to bulb. Some can do well in parts of the upper southern U.S. all the way up through Maine. Others are best for mid-latitudes only (35-40°). All intermediate-day onions in our catalog have performed well repeatedly in our Maine trials.
• Short-day: Suited for the South, below latitude 36°, bulbing when the day length measures between 10–12 hours. We don’t offer seed for short-day varieties.)

About 200-250 seeds/g, 5,700-7,000 seeds/oz.

Growing Onions

Shallow rooted, onion require rich weed-free soil and consistent water. All other factors being equal, onions grown from seedlings will grow bigger and resist disease better than set-grown onions.

• Planting: Plant seedlings and sets in spring as soon as soil is workable (onion plants come with planting directions). Onions survive light frosts.
  • Seedlings: Set seedlings out in shallow trenches 1–2" deep. Plant 6–8" apart, with 1–2' between rows.
  • Sets: Plant onion sets 3" apart in rows 1' apart. Thin to 6" apart as they grow (or plant them 4–6" apart if you don’t want to thin).
• Growing: Mulch when they are 1' tall. During the season, pull any plants that begin to bolt and use them as scallions. It’s a good idea to sidedress once or twice a season, especially close to summer solstice.
• Harvest: After half the onion tops fall, push over the remainder and harvest within a week.
• Curing: Field-cure in the sun about 10 days until dry, covering with a tarp in wet weather. In the event of extreme heat or prolonged damp conditions, we recommend sheltered curing in a well-ventilated barn or greenhouse. Curing is essential for long storage.
• Storage: Store cured onions in mesh sacks in a cool dry well-ventilated place, periodically removing sprouting or rotting bulbs. Ideal storage conditions are temperatures at 32° with humidity of 60–70%. If you can’t do that, work to get a total number of 100. For example, at temperatures from 50–55°, humidity should be 45–50%. In spring, put your remaining onions in the fridge to extend storage until your new crop is ready.

Note: Onion seed is short-lived. Retest 1-year-old seed before using. Discard anything older.