In New York City, the sowing window for unusual root crops opens around the last spring frost, which NOAA’s 1991-2020 normals place between March 23 and April 3. It closes ahead of the first fall frost, due between November 14 and November 27. Hardy roots go in first and tender ones wait. These are city dates, and upstate they shift a lot.
The short answer for New York
Sow hardy roots such as salsify, scorzonera and parsnip as soon as the soil can be worked in spring. Set out tender ones such as oca and yacon only after the last frost window closes in early April. Both calls rest on New York City figures: the 1991-2020 NOAA climate normals put the last spring freeze between March 23 and April 3, and the first fall freeze between November 14 and November 27.
Those dates are probabilities of a 32°F freeze, specifically the band where the odds fall between 30 and 70 percent. Read them as a coin flip that slowly tilts, not as a deadline. A garden planted on March 25 is gambling a little. One planted on April 10 is gambling much less.
Count the gap between the end of the spring band and the start of the fall one and you get more than seven months of mostly frost-free ground in the city. That is generous for most roots. The slow ones need all of it, and the tender ones need the warm middle of it.
| Type | Examples | Timing in New York City |
|---|---|---|
| Hardy, slow-growing | Salsify, scorzonera, parsnip | Sow in early spring once soil is workable, even inside the frost band |
| Tender, warm-season | Oca, yacon, mashua | Plant after April 3, lift before the November 14 to 27 band |
The city’s coldest month has a mean daily minimum of 27.9°F, according to the same NOAA normals. That is an average of the lows, not the coldest night ever recorded, so some nights run colder. It does explain why hardy roots left in mulched ground can carry through winter in the city while tender ones cannot. For crop-by-crop picks, see The Best Unusual Roots to Grow in New York.
What will not work here
The most common failure is borrowing the city’s dates for a garden that isn’t in the city. Central Park is a dense urban site, and it holds heat. Upstate New York and the Adirondacks frost much earlier in fall and later in spring. A reader in the Adirondacks who sows on April 1 because the city allows it is planting into frozen or cold, waterlogged ground.
Second, tender roots on a short clock. Oca, yacon and mashua are plants of long, frost-free seasons. In the city, a window running from early April to mid-November gives them room. Move that window north and it shrinks from both ends, and the plants may be hit by frost before the tubers have bulked up. That is a disappointing harvest of pencil-sized tubers, not a catastrophe, but it is the usual result.
Third, the slowest hardy roots punished by late sowing. Salsify and scorzonera are not fast. Sow them in June because spring got away from you and they will meet the first fall freeze (November 14 to 27 in the city, earlier elsewhere) as small, thin roots. Parsnips behave the same way. Early sowing is the whole strategy, which is why the coin-flip frost band matters less for them than the soil being workable.
Fourth, the March 23 gamble for anything tender. The band is a 30 to 70 percent chance of a 32°F freeze, so planting a frost-tender root at the front edge means you could lose it to a single clear night. Tubers and slips of tropical roots don’t recover from a hard freeze the way a parsnip seedling shrugs off a light one.
Last, a caveat on what this page lacks: it carries no rainfall or humidity figure for the state, so it can’t say how tightly to space plants in a wet summer. As a general rule, crowded foliage dries slowly and invites leaf disease, so lean toward wider spacing if your summers run humid.
What changes across New York
New York is not one garden. The USDA Plant Hardiness Zone Map (2023 edition, built on 1991-2020 normals) lists the state as spanning zones 3b to 7b. That is four full zones, and the system rests on a single variable, the average annual extreme minimum temperature. There is no single answer for the whole state, only a spread, with the Adirondacks and high ground at the cold end and the New York City area at the warm end.
The zone number is a winter-survival score, not a planting date. It tells you whether a perennial root such as Jerusalem artichoke or a hardy biennial left in the ground will make it through, and it says little about how many frost-free weeks you have. The two usually move together anyway, since colder places also tend to start later and stop earlier.
If you garden north or at altitude
Shift three things. Sow hardy roots later in spring, once the ground has truly thawed and dried, because the city’s March band does not apply to you. Bring your fall deadline forward and favor roots that tolerate a cold finish. Treat tender crops as a bigger gamble, and consider starting them indoors or skipping them. This page does not have county-level frost dates, so it cannot put a number on the shift.
Which zone you are in is not something this page can tell you. Look your location up on the USDA map by ZIP code. For a broader overview of these crops across the state, see Growing Unusual Root Crops in New York.
Where to check this for your own county
Your state extension service is the next stop. In New York that is Cornell Cooperative Extension, which runs offices at the county level. Staff there know the local frost pattern, the local soils and what has actually grown in your area.
Look for two things. First, a local planting calendar, which will usually be published by crop and will give dates for your part of the state. Second, any varieties trialled in your county, meaning grown side by side and compared, as opposed to simply listed in a catalog. A variety that performed in a trial a few counties over is better evidence than any general rule.
A county recommendation beats a state one, and this page is the state one. It runs on a single reference station, New York City, and it has no extension calendar for unusual roots to cite. If your county office gives a date that disagrees with the one here, trust the county.
Go in with a question that is easy to answer, like: “When do you stop expecting a hard freeze here, and which root crops have done well in trials nearby?” Extension staff get plenty of vague questions, and specific ones get specific answers. Ask about the first fall frost too, since it sets the other end of your window.
Checking this against your own garden
Every date above is an average over thirty years, and your yard is one particular place. What you observe outranks the calendar. Three things are worth watching, and none needs an instrument.
- Soil warmth by feel. Push a bare hand a few inches into the bed in the morning. If it feels cold and clammy and clumps in a wet ball, wait. Beds that warm early are sheltered or well drained, and beds that lag are low or shaded.
- The first male flowers on squash. Squash and zucchini put out male blooms before female ones. The date they appear, in your beds or a neighbor’s, is a marker of how warm your site runs. Write it down and compare year to year.
- The first true leaves. After the rounded seed leaves come the first true leaves. How fast your direct-sown roots reach that stage tells you about germination conditions. A slow bed has a cooler microclimate, and it tells you to sow there earlier next time.
Keep a few lines in a notebook each year. After three seasons you will have a local calendar that no state page can match.
Common questions
Can I plant unusual roots in New York before the last frost date?
Hardy ones, yes, once the soil can be worked. Salsify, scorzonera and parsnip tolerate cold. Tender roots like oca and yacon should wait until after the March 23 to April 3 band, the New York City figure, has passed.
Are the March 23 to April 3 dates right for all of New York?
No. They are the NOAA 1991-2020 figures for New York City. Upstate and the Adirondacks see later spring frosts and earlier fall ones, so your dates will differ.
What does the fall frost date mean for roots?
In New York City the first fall freeze falls between November 14 and November 27. Tender roots must be lifted before then. Hardy roots can stay in mulched ground, though you will want to harvest some before the soil freezes hard.
Which hardiness zone is New York?
The USDA map spans 3b to 7b across the state, so there is no single zone. Check the USDA Plant Hardiness Zone Map for your own location.