Potato Onion
Allium cepa
HOW TO GROW ONION
Start indoors 8–10 weeks before last frost, plant out 4 weeks before frost. For fall harvest, transplant 11 weeks before first frost. Short-day onions produce bulbs in 11-12 hours of light, long-day onions in 14-16 hours. The dividing line is 36˚, about the KA/OK border. Plant long-day varieties north of this line and short-day south. Direct sow thickly as soon as soil can be worked. If tops reach 5” before transplant, cut to 1-3” to increase girth. Transplant seedlings in shallow trench 2-7” apart. Hill sides slightly after 4-5 weeks. Knock the rest of the tops over when 60 percent have fallen. After 3 days, pull and sun-cure 7–10 days in field rotating every few days before twisting off tops and storing. Soil pH 6.2-7.5. Hardiness zones 3-10. Biennial.
Days from maturity calculated from the date of seeding. Average 6,500 seeds per ounce. Average 580M seeds per acre. Federal germination standard: 70%. Usual seed life: 2–3 years. Isolation distance for seed saving: 1 mile.
Planting Depth 1/8-1/4”
Soil Temp. Germ. 55-75˚F
Days to Germ. 7-14
Plant Spacing 4-8”
Row Spacing 12-18”
Storage Refrigerate
Full Sun, Moist Well Drained
Days from maturity calculated from the date of seeding. Average 6,500 seeds per ounce. Average 580M seeds per acre. Federal germination standard: 70%. Usual seed life: 2–3 years. Isolation distance for seed saving: 1 mile.
Planting Depth 1/8-1/4”
Soil Temp. Germ. 55-75˚F
Days to Germ. 7-14
Plant Spacing 4-8”
Row Spacing 12-18”
Storage Refrigerate
Full Sun, Moist Well Drained
- 100 Seeds$3.50
- 1000 Seeds$18.50
Potato onions are a perennial bunching onion. Potato onions can be grown season after season similar to shallots. Like shallots, larger potato onions will start dividing after their first season of growth. This selection includes mostly white onions, but some of the onions have brown or even light red skins.
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Potato onions are a perennial bunching onion. Potato onions can be grown season after season similar to shallots. Like shallots, larger potato onions will start dividing after their first season of growth. This selection includes mostly white onions, but some of the onions have brown or even light red skins.
These potato onions are delicious, spicy and exceptionally good storage onions. They will keep for up to 12 months if stored on a shelf in a single layer with good air circulation in a cool room/garage/cellar. They also over-winter very well in our zone 7 winters. When grown from seed, onion bulbs can get quite large in their first year (up to and larger than baseball size) under the right conditions. Harvest onions when about half of the tops have fallen over. Harvest the whole cluster, or take just a few and leave the rest to continue to grow/spread.
Potato onions can also be grown as annuals from seed as you would grow any other standard onion, and they do very well that way. When grown perennially, I am finding that many of the first year onions will go to seed. I am saving those onions that don't go to seed for perennial growing and replanting early in the year after selecting the best storage onions from relatively warm conditions indoors. The larger onions that are replanted will split into 4-8 new onions.
You can grow perennial onions indefinitely this way but the cloned onions will no longer produce seed and may become successively smaller over several years until they reach shallot size onions. I personally will be introducing first year seed grown onions into my personal supply every year so that we can enjoy medium through large size onions year after year.
Our original seed came from Andy's Green Mountain Multiplier Onion and I want to acknowledge and thank him here for his hard work in breeding, saving seed and distributing seed, bringing this once popular, but now rare form of onion back from obscurity! Tags: Harvest: Mid, Size: Medium, Specialty: Storage, Heritage: Heirloom, Season: Spring Fall.
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