Yes — Strong Match
radicchio is grown in zones 3-10, which covers every zone New Hampshire contains (3b-6b). Whether the season is long enough is the question that remains.
Radicchio in New Hampshire — the short answer
Radicchio in New Hampshire: grown in zones 3–10, full sun.
- Plant zones
- 3-10
- Not verified — NC State Extension Gardener Plant Toolbox lists zones 3a–8b
- New Hampshire zones
- 3b-6b
- USDA PHZM 2023
- Frost window
- Apr 22 - May 4 – Oct 10 - Oct 21
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 145 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 65 days
- Growable Ground Plant Database
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
New Hampshire spans zones 3b-6b, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score radicchio against your parcel's actual hardiness, soil, and sun.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your parcel report in seconds — read in full free for your first 14 days
New Hampshire is not one climate
A single New Hampshire answer averages 10 counties whose growing seasons are 43 days apart — from 145 frost-free days in Coos County to 188 in Rockingham County. Which end of that your land sits nearer changes what radicchio can finish before the first hard freeze.
The middle half of 10 counties runs 159–183 days, with a median of 169 days — a 43-day span end to end.
Measured across 10 New Hampshire counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where in New Hampshire Fits Best
Even within New Hampshire's zones 3b-6b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for radicchio (USDA PHZM 2023):
Zone Comparison
Radicchio Needs
- USDA Zones: 3-10
- Sun: Full Sun
- Mature size: 1 ft tallWe haven't confirmed this against a published source yet.
- Picking window: ~14 days of harvestWe haven't confirmed this against a published source yet.
- Drought tolerance: Medium
New Hampshire Has
- USDA Zones: 3b-6b
- Last Hard Freeze (28°F): Apr 22 - May 4
- First Hard Freeze (28°F): Oct 10 - Oct 21
- Annual Rainfall: 36-50 inches
- Common Soils: Glacial till, Sandy loam, Rocky loam
Plant Zone Range (zones 3-10)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Radicchio in New Hampshire
The frost window
Across New Hampshire, the last spring hard freeze (28°F) clears between Apr 22 and May 4, and the first fall hard freeze lands between Oct 10 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 159-day window you can count on — up to 182 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
When to start the seed
Those dates are when radicchio goes out, not when it starts. It is sown under cover about 4 weeks ahead, so counting back from New Hampshire's late-side last freeze of May 4 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Winter standing
New Hampshire runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for radicchio, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether radicchio is a permanent planting or a replant-every-spring crop for you turns on your own zone within New Hampshire; check its hardiness range against that before treating it as long-lived ground.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
Radicchio is grown in zones 3–10, which covers every zone New Hampshire contains (3b-6b). We have no sourced winter-survival figure for radicchio, so this page does not say whether it overwinters here. New Hampshire's typical season runs ~171 frost-free days against the ~90 radicchio needs.
Growing degree days
Radicchio needs ~1300 GDD (base 50°F) to ripen. We haven't confirmed this against a published source yet. The state median runs ~1870 GDD (from PRISM 1991-2020 climate normals), so New Hampshire's typical season clears that easily.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Radicchio tolerates a wide pH range (pH 4.5-8.3) — 3.8 units, acid ground through alkaline — so soil acidity is rarely what limits it in New Hampshire. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 6 and 7.5 — worth knowing before you decide whether a New Hampshire soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your New Hampshire site is heavier clay or sits in a low spot, a raised bed lifts the roots above wet ground, or work in compost.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. New Hampshire soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Before you plant radicchio for food
Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before radicchio goes in. What follows is New Hampshire’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.
Safe to Grow Here?
What the federal record shows across New Hampshire — and how to grow with it.
We checked the federal record across New Hampshire — 5,738 documented sites across 7 of the 8 source types we track.
The most significant on record: 82 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
New Hampshire carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds of imported, lab-tested soil grow well almost anywhere in the meantime.
Sources Checked
across New Hampshire
Severity Distribution
across New Hampshire
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •TRI facilities report what they release. Check the wind — downwind beds catch more of it.
- •Near a brownfield, a raised bed of imported, lab-tested soil lowers contact with the ground; it does not remove it.
Sources: EPA, USGS — 950K documented sites tracked nationwide across 8 federal source types.
What Else to Consider for Radicchio in New Hampshire
The zone range tells you where radicchio is grown — but New Hampshire growers also need to think about:
Very short season in the White Mountains (80-100 frost-free days)
Rocky glacial soils throughout the state
Harsh winters with deep snow cover
What to actually do about these — and the constraints that apply to every New Hampshire grower, not just radicchio — is covered on the New Hampshire growing guide.
Where in New Hampshire Radicchio Is Zone-Hardy
Radicchio is rated for USDA zones 3–10. Every one of New Hampshire’s 10 counties sits inside that band — from Coos County at zone 4b to Strafford County at zone 6a — so winter cold is not what decides this plant anywhere in the state. What is left to vary is your own parcel: slope, shelter and cold-air drainage routinely move a site half a zone either way from the county figure.
Across those 10 counties New Hampshire’s winter-low ladder runs from zone 4b in Coos County to zone 6a in Strafford County — 1.5 USDA zones of spread, which is 15°F between the two counties’ average coldest night of the year. That is why a statewide hardiness answer is where you start and not where you finish.
The planting window moves with it. Coos County holds its last hard freeze (28°F) until about May 13, while Rockingham County is clear by Apr 17 — 26 days apart. Set radicchio out on your county’s date, not the state’s.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F killing freeze — earlier than the folk 32°F "last frost". Radicchio’s zone 3–10 band: Not verified — NC State Extension Gardener Plant Toolbox lists zones 3a–8b. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Radicchio draws honeybees and native bees (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, radicchio can only work that bloom inside New Hampshire's frost window — roughly 171 days, opening after the last 28°F freeze (Apr 22 - May 4) and closing at the first (Oct 10 - Oct 21), per NOAA Regional Climate Centers ACIS, 1991-2020. Pollinator value: We haven't confirmed this against a published source yet.
New Hampshire Cooperative Extension
For New Hampshire-specific cultivar recommendations, planting calendars, and pest pressure for radicchio, the canonical source is UNH Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Radicchio native to New Hampshire?
No — the USDA PLANTS Database lists Radicchio as introduced rather than native in the Lower 48, so it is not part of New Hampshire's native flora. It grows here as a garden plant; pairing it with a few New Hampshire natives keeps local pollinators fed too.
Looking for plants that belong here? The New Hampshire growing guide lists plants that USDA PLANTS records growing in New Hampshire and that Kew and NatureServe Explorer both list in its native range, leaving out any that NatureServe flags as exotic there or that our audit holds.
State records: USDA PLANTS Database state-distribution data (presence, not state-level nativity), accessed 2026-10-19.
Common Questions About Growing Radicchio in New Hampshire
When can I plant Radicchio in New Hampshire?
New Hampshire's last spring hard freeze (28°F) clears between Apr 22 and May 4, and the first fall hard freeze lands between Oct 10 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Radicchio, so this page does not state whether it overwinters in New Hampshire and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.
What hardiness zone is Radicchio grown in across New Hampshire?
New Hampshire spans USDA hardiness zones 3b-6b (USDA ARS PHZM 2023). Radicchio carries a range of zones 3-10, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical New Hampshire site have?
A typical New Hampshire site sees ~171 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Radicchio needs 90+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Radicchio native to New Hampshire?
No — the USDA PLANTS Database lists Radicchio as introduced rather than native in the Lower 48, so it is not part of New Hampshire's native flora. It grows here as a garden plant; pairing it with a few New Hampshire natives keeps local pollinators fed too.
How should I amend the soil for Radicchio in New Hampshire?
Radicchio tolerates pH 4.5-8.3 and well (dry spells) drainage (FAO ECOCROP). That is a 3.8-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a New Hampshire site — amend for drainage and organic matter first.
Will Radicchio actually grow on my specific land in New Hampshire?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores radicchio against your address's mapped soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in New Hampshire
State-level data is a sketch. Your Growable Ground report scores radicchio against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.
Three things about your lot that New Hampshire radicchio averages can't show:
We read public map data around New Hampshire — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the New Hampshire radicchio average
Explore More
Growing guides for radicchio
Explore New Hampshire county by county
New Hampshire carries 10 counties with their own USDA zone — a sample of the growing pages for radicchio there:
Where else radicchio grows
Radicchio's zone band crosses state lines — these are the states closest to New Hampshire in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in New Hampshire
New Hampshire has a growing page for 807 plants — a rotating sample of the rest of the shelf.
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