Castine, Maine, sits in USDA hardiness zone 5b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Among the crops suited to this profile: cabbage, cranberry, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Castine, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Castine lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Castine — soil, climate, flood, and parcel records. How we handle your address.
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Castine — the short answer
Castine, Maine: USDA zone 5b, about 200 days between hard freezes, across 987 acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 13
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~200
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 987 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 5b is Castine's average, not your lot's — a low corner or a tree line moves it. Against Castine's 200-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Castine
Each reading below is measured for Castine itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCastine runs about 200 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredCastine sits in USDA hardiness zone 5b.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Castine is in
Castine sits in the Acadian Plains and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Castine's own centroid rather than borrowed from Hancock County.
What Grows in Castine
Every plant below cleared Castine's own zone 5b and its 200-day season. Each card opens that plant's Maine profile. How we score.
Is it too late to plant in Castine?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 16; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 30 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
Documented around Castine
Survey cells within 31 miles of Castine checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 33 miles off. What to watch for.
What's on the federal record near Castine
Closest first, within ~10 miles of Castine. Listing isn't leaking, and distance isn't exposure.
- ZEKESUnderground Storage Tanks · 1900 ft
- MAINE MARITIME ACADEMYUnderground Storage Tanks · 2300 ft
- POLLUTION CTRL CTR PUMP STAUnderground Storage Tanks · 2600 ft
- 12 WATER ST LLC DBA T & C GROCERYUnderground Storage Tanks · 0.6 mi
- MAINE MARITIME ACADEMYBrownfields · 0.6 mi
- EATONS BOAT YARD INCUnderground Storage Tanks · 0.6 mi
- Castine ProspectMining · 0.8 mi
- Abner GrayMining · 1.3 mi
- Emerson MineMining · 2.0 mi
- Emerson & North CastineMining · 2.0 mi
- Emerson-North Castine ProspecMining · 2.0 mi
- North Castine MineMining · 2.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Castine's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Castine.
Sources Checked
within ~10 miles of Castine
Severity Distribution
within ~10 miles of Castine
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Castine, two things run higher than the national average within ~10 miles of Castine — Mining (88 sites) and Superfund (3 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Castine
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Castine average
Your land is one point inside Castine
Everything above resolves to Castine as a whole — one PHZM band and one 28°F frost record, read across 987 acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at town scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Castine Average
Castine Average
- ●USDA Zones 5b, averaged across Castine
- ●One soil character for all of Castine
- ●Frost dates read at Castine's scale: Apr 13 to Oct 30
YOUR Parcel
- ✓Your exact zone, not Castine's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Castine
Pull a site-specific report for your exact address in Castine, Maine — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Castine averages can't show:
We read public map data around Castine — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Castine average
How we know this about Castine
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Castine’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Castine
When does frost risk typically end in Castine?
The last hard freeze (28°F) in Castine typically lands around Apr 13, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about May 4.
When is the first frost in Castine?
The first hard freeze (28°F) in Castine typically arrives around Oct 30, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 16, so the watching starts about Sep 30 — about 200 days after the spring freeze cleared.
How long is the growing season in Castine?
Measured between 28°F hard freezes, Castine sees about 200 frost-free days — roughly Apr 13 through Oct 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 4 to Oct 16, about 165 days.
Is the soil safe to grow vegetables in Castine?
The federal record around Castine runs heavier than most — 196 documented sites, mostly Mining entries (88), the nearest Underground Storage Tanks record about 0.4 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Castine?
From about Sep 30 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 30 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 30. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Castine's scale — its 5b band and its 200-day season. Your yard writes its own version of Castine's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Castine’s own scale
7 of the readings below were taken at Castine's own scale — its own ~200-day season between 28°F freezes, the 987 acres it covers and 196 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Castine's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Castine's own 28°F hard-freeze dates, about Apr 13 and Oct 30 and the ~200-day span between themNOAA 1991–2020 Climate Normals
- 196 documented contamination sites on the federal record near Castine, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Castine's boundary and the 987 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~200-day seasonGrowable Ground crop-matching engine
- The ecoregion at Castine's own centroid, the Acadian Plains and HillsUS EPA Level III Ecoregions
- Lanternfly survey cells around Castine checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Castine's 987 acres read through its county's SSURGO summaryfrom Hancock County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Hancock County
- The growing challenges every Maine grower plans around — written at state scale, so they stay on the state guidefrom Maine
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Hancock County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Castine's 987 acreswhy one lot differs from the next →
- Which side of Castine you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 987 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.4 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Castine-wide figureread your own land →
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