The Best Onion Varieties for New York

New York sits at 40.78°N (the latitude of the Central Park weather station in Manhattan), and on the longest day of the year the sun stays up for 14 hours and 56 minutes there. That single number decides which onions will actually form a bulb in a New York garden: long-day and intermediate-day varieties are built for exactly this kind of daylight, and 19 of the varieties documented on this site fall within a range that covers this latitude.

The short answer for New York

An onion doesn’t bulb because the weather warms up. It bulbs because the days get long enough to trigger the switch from leaf growth to bulb growth, and different varieties are bred to wait for different day lengths. At 40.78°N, with just under 15 hours of daylight at the peak of summer, New York gardens sit squarely in long-day and upper intermediate-day territory. That’s the group to shop from, full stop.

Long-day varieties for New York

These varieties wait for something close to 14 to 16 hours of daylight before they start swelling underground, which is exactly what a New York summer delivers. Ten of them have published ranges that cover 40.78°N:

• Ailsa Craig
• Barolo
• Blush
• Bridger
• Frontier
• New York Early
• Patterson
• Red Carpet
• Rossa di Milano
• Walla Walla Sweet

Intermediate-day varieties for New York

Intermediate-day types split the difference, bulbing around 12 to 14 hours of daylight. Nine of them are documented as covering this latitude:

• Cabernet
• Calibra
• Elsye
• Expression
• Monastrell
• Red Long of Florence
• Red Long of Tropea
• Scout
• Sierra Blanca

Three more sit close enough to the edge of their published range that they belong in a separate category rather than a flat yes: Candy, Safrane, and Talon. They may bulb reliably in New York, but a gardener choosing one of these three is working at the margin of what the catalog data supports, not in the middle of it.

What will not work here

This is the part of the conversation most seed racks skip, and it’s the reason a lot of home gardeners end up with a bed of onion leaves and nothing underneath. Day length is not a soft preference for an onion, it’s a trigger, and a variety built for the wrong trigger doesn’t just underperform. It fails in a specific, predictable way depending on which direction it’s wrong in.

Short-day varieties: bulbs that stay tiny

Short-day onions are built to start bulbing at around 12 hours of daylight, which in a place like New York arrives in early spring, long before the plant has had time to grow much leaf. The plant obeys the signal anyway. It starts making a bulb out of whatever small amount of leaf it has, and the result is an onion the size of a golf ball, sometimes smaller. Seven varieties in this line fall into that category for New York:

• Gabriella — short-day, rated for 20-35°N, bulbs far too early here and stays small
• Madalyn — short-day, rated for 20-35°N, same problem
• Red Rock — short-day, rated for 30-36°N, triggers before the plant has grown
• Red Sensation — short-day, rated for 25-35°N, undersized bulbs in New York’s longer days
• Texas Grano 1015Y — short-day, rated for 25-35°N, bulbs too soon to size up
• Vidora — short-day, rated for 25-35°N, same early-trigger issue
• White Castle — short-day, rated for 30-38°N, still too far south for this latitude

Long-day varieties bred for even longer days: no bulb at all

Two varieties fail in the opposite direction, and the failure is worse. Powell (rated for 43-47°N) and Redwing (rated for 43-65°N) are bred for day lengths that New York’s summer never reaches. These plants don’t just underperform, they never get the signal to bulb. They spend the season making leaves, and when fall arrives and the plant goes into decline, what’s under the soil rots instead of curing. Planting either one in a New York garden is not a small mistake with a small onion at the end. It’s a full season with no onion at all.

What changes across New York

New York City, where the 40.78°N reference figure comes from, sits at the southern edge of the state. Long Island runs a little south of that, and the state stretches north from there past Albany and into the North Country near the Canadian border, where latitude climbs into the mid-40s. That’s not a rounding error. It’s the difference between a garden that behaves exactly like the reference numbers on this page and one that runs closer to a different day-length group entirely.

A gardener in Plattsburgh isn’t gardening under the same sky as a gardener in Brooklyn, even though both are technically “New York.” If you’re near either edge of the state, the honest move is to check your own latitude rather than borrow the Central Park number wholesale.

Sweet now, or onions that last

Every onion grower eventually runs into this trade-off, and it isn’t a matter of luck or variety marketing. It’s chemistry. The compounds that give an onion its sharp bite and make your eyes water when you cut into it are volatile sulfur compounds, and those same compounds double as a preservative. According to University of Missouri Extension, “‘sweet’ onions do not store as well as the more pungent types.” Fewer sulfur compounds means a milder onion on the cutting board today and a softer, sprouting onion in the pantry by January.

This lines up with the day-length pattern that already shapes what grows where. Southern gardens, running on short-day varieties, tend to produce sweeter onions with a shorter shelf life. Northern gardens like New York’s, working with long-day and intermediate-day varieties, tend toward the sharper end of the spectrum, and that sharpness is exactly what buys extra months in storage. A New York gardener isn’t stuck choosing between “good” and “bad” onions. The choice is closer to eating well this fall or eating onions you grew yourself well into March. If you want the sweeter, milder eating experience, look for a variety described as mild or sweet and plan to use it up within a few weeks of harvest. If you want a pantry that’s still stocked at the end of winter, favor the pungent end and store the bulbs somewhere cool, dark, and dry.

Checking this against your own garden

None of the numbers above replace a look at your own backyard. The 40.78°N figure describes New York City specifically, and a garden fifty or a hundred miles away is working with a different sky. Before you commit to a variety, run through a short list of checks that take less time than reading a seed catalog cover to cover:

• Look up your own latitude if you’re more than about half a degree away from New York City, especially if you’re in the North Country or along Lake Ontario
• Confirm your local last and first frost dates rather than assuming they match downstate figures
• Call or check the website of your county’s Cornell Cooperative Extension office, which keeps localized planting calendars for exactly this reason
• If you’re growing Safrane, Talon, or Candy, treat the first season as a trial rather than a guarantee, since these sit right at the edge of their published range
• Note your soil’s drainage and typical spring wetness, since bulbing onions still need the basic growing conditions right even when the day-length math checks out

A latitude figure tells you which group of onions to buy. It doesn’t replace the ten minutes it takes to confirm your own frost dates before seed goes in the ground.