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Maine

Planting zones in Aroostook County, Maine

This county spans USDA zones 3b to 5a, so there is no single zone for Aroostook County and anyone who gives you one is rounding. 54% of its ZIP codes are zone 4a; the rest are not.

USDA zones 3b–5a 4 zones across 41 ZIP codes
ZIP codes 41 41 have a NOAA station within range
Weather stations 14 NOAA 1991–2020 normals, across 6,671 sq mi

Your ZIP code

Get the exact answer for your address

Everything above describes Aroostook County, Maine as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact — enter it and this page will tell you your zone, which NOAA station it comes from and how far away that station is.

Works for all 40,502 US ZIP codes. Freeze dates need a NOAA station within 100 km; where there is none, the page says so rather than estimating one.

The growing season in Aroostook County is closing

Nothing in the 32-crop table still has time to mature here. The first fall freeze normally arrives September 13 – October 2 across the 14 NOAA stations serving this county .

Your next season already has a date

The first job of it is 🧅 Green Onions, start indoors, around March 11 – April 7 — counted back from a last spring freeze of May 6 – June 2 here.

Every spring date for your ZIP →

These are ranges across the whole county. The ZIP lookup above gives the dates from your own nearest station instead.

Growing season across Aroostook County A one-year bar. Every one of the 14 NOAA stations serving this county counts June 2 to September 13 as growing season, 103 days. At least one counts May 6 to October 2, 149 days. The same figures are written out below this chart. JFMAMJJASONDJune 2September 13

All 14 stations agreeAt least one station

Every one of the 14 NOAA stations serving this county counts June 2 – September 13 as growing season (103 days). Widening to any single station gives May 6 – October 2 (149 days).

That is a 46-day difference inside one county — which is why this page gives ranges rather than a single planting date. The ZIP lookup above resolves it to one station.

Which zone you are in depends where you are

Aroostook County covers 4 hardiness zones. A guide that gives the county one zone has picked whichever is largest and rounded everyone else into it — fine for the 54% in zone 4a and wrong for the other 46%. Here is the actual split.

Zone ZIP codes Share  
4a 22 54%
4b 14 34%
5a 4 10%
3b 1 2%

Zones are published per ZIP code, so yours is exact even though the county's is not. The hardiness tool will tell you which one you are in.

Your freeze dates

Last spring freeze May 6 – June 2
First fall freeze September 13 – October 2

Across the 14 NOAA stations serving this county. These are medians — half of years freeze later than the date shown — so treat the later end of each range as the cautious one.

The growing season runs 102–147 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 72.9–76.9 °F in June–August. Summer rain over the same months runs 11.2–12.7" across those 13 stations, against the rough inch a week — about 13 inches over the same 92 days — that a vegetable garden is usually reckoned to want. The middle station covers about 90% of it, so expect to make up the rest. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 75 °F summer afternoon drying the soil faster than a cool one.

Every ZIP code in Aroostook County

Zones are published per ZIP code, not per county, so this is the exact answer rather than the county's average. The station column is the nearest one to that ZIP code's centroid and how far away it is — the same figure the tools use, shown here so you can see which ZIP codes are well covered and which are reaching.

ZIP code USDA zone Nearest NOAA station Distance
04451 5a Danforth, ME 28.8 km
04459 5a Millinocket Wastewater, ME 26.7 km
04471 4b Houlton INTL AP, ME 23.5 km
04497 4b Danforth, ME 16.9 km
04730 4b Houlton 5N, ME 2.2 km
04732 4a Presque Isle, ME 38.0 km
04733 5a Millinocket Wastewater, ME 23.5 km
04734 4a Bridgewater, ME 8.8 km
04735 4b Bridgewater, ME 15.1 km
04736 4a Caribou Muni AP, ME 4.6 km
04737 3b Clayton Lake, ME 0.6 km
04739 4a Ft Kent, ME 29.1 km
04740 4a Presque Isle, ME 12.5 km
04742 4a Caribou Muni AP, ME 16.0 km
04743 4b Ft Kent, ME 12.5 km
04745 4b Frenchville Aroostook AP, ME 6.5 km
04746 4a Frenchville Aroostook AP, ME 13.4 km
04747 4b Patten 2, ME 23.2 km
04750 4a Limestone 4 Nnw, ME 2.0 km
04756 4b Frenchville Aroostook AP, ME 4.2 km
04757 4a Presque Isle, ME 17.1 km
04758 4a Bridgewater, ME 14.6 km
04760 4a Bridgewater, ME 11.9 km
04761 4b Houlton INTL AP, ME 14.1 km
04762 4a Caribou Muni AP, ME 13.9 km
04763 4b Houlton INTL AP, ME 25.3 km
04764 4b Bridgewater, ME 38.7 km
04766 4a Caribou Muni AP, ME 15.3 km
04768 4a Allagash, ME 32.5 km
04769 4a Presque Isle, ME 4.0 km
04772 4a Frenchville Aroostook AP, ME 5.6 km
04773 4b Frenchville Aroostook AP, ME 7.1 km
04774 4b Allagash, ME 4.0 km
04776 5a Patten 2, ME 27.2 km
04779 4a Frenchville Aroostook AP, ME 18.8 km
04780 4b Patten 2, ME 24.0 km
04781 4a Ft Kent, ME 9.8 km
04783 4a Caribou Muni AP, ME 22.4 km
04785 4a Van Buren 2, ME 8.9 km
04786 4a Caribou Muni AP, ME 15.7 km
04787 4a Presque Isle, ME 13.8 km

ZIP-code positions are area centroids, so a large rural ZIP code's listed distance is measured from the middle of its area rather than from any particular address in it.

When to start seeds in Aroostook County

Every date below is anchored on the last spring freeze at each station and reported as a range across all 14 of them, because no one station speaks for the county.

Crop Job When Offset
🧅 Green Onions Start indoors March 11 – April 7 8 wk before
🌶️ Peppers Start indoors March 11 – April 7 8 wk before
🥦 Broccoli Start indoors March 25 – April 21 6 wk before
🥬 Cabbage Start indoors March 25 – April 21 6 wk before
🥬 Collards Start indoors March 25 – April 21 6 wk before
🥬 Kale Start indoors March 25 – April 21 6 wk before
🥬 Leaf Lettuce Start indoors March 25 – April 21 6 wk before
🫛 Peas Direct sow March 25 – April 21 6 wk before
🥬 Spinach Direct sow March 25 – April 21 6 wk before
🍠 Sweet Potato Start indoors March 25 – April 21 6 wk before
🍅 Tomatoes Start indoors March 25 – April 21 6 wk before
🥬 Bok Choy Start indoors April 1 – April 28 5 wk before
🥬 Kohlrabi Start indoors April 1 – April 28 5 wk before
🥬 Swiss Chard Start indoors April 1 – April 28 5 wk before
🥬 Arugula Direct sow April 8 – May 5 4 wk before
🥬 Baby Salad Greens Direct sow April 8 – May 5 4 wk before
🥕 Beets Direct sow April 8 – May 5 4 wk before
🧅 Green Onions Direct sow April 8 – May 5 4 wk before
🥬 Mustard Greens Direct sow April 8 – May 5 4 wk before
🌶️ Okra Start indoors April 8 – May 5 4 wk before
🌱 Radishes Direct sow April 8 – May 5 4 wk before
🥔 Turnips Direct sow April 8 – May 5 4 wk before
🥬 Cabbage Set out April 15 – May 12 3 wk before
🥕 Carrots Direct sow April 15 – May 12 3 wk before
🥬 Collards Direct sow April 15 – May 12 3 wk before
🥬 Collards Set out April 15 – May 12 3 wk before
🥒 Cucumbers Start indoors April 15 – May 12 3 wk before
🧅 Green Onions Set out April 15 – May 12 3 wk before
🥬 Kale Direct sow April 15 – May 12 3 wk before
🥬 Kale Set out April 15 – May 12 3 wk before
🥬 Kohlrabi Direct sow April 15 – May 12 3 wk before
🥬 Kohlrabi Set out April 15 – May 12 3 wk before
🥬 Leaf Lettuce Direct sow April 15 – May 12 3 wk before
🎃 Pumpkins Start indoors April 15 – May 12 3 wk before
🎃 Summer Squash Start indoors April 15 – May 12 3 wk before
🎃 Winter Squash Start indoors April 15 – May 12 3 wk before
🥒 Zucchini Start indoors April 15 – May 12 3 wk before
🥬 Bok Choy Direct sow April 22 – May 19 2 wk before
🥬 Bok Choy Set out April 22 – May 19 2 wk before
🥦 Broccoli Set out April 22 – May 19 2 wk before
🌿 Cilantro Direct sow April 22 – May 19 2 wk before
🥬 Leaf Lettuce Set out April 22 – May 19 2 wk before
🥬 Swiss Chard Direct sow April 22 – May 19 2 wk before
🥬 Swiss Chard Set out April 22 – May 19 2 wk before
🌿 Dill Direct sow April 29 – May 26 1 wk before
🫘 Bush Beans Direct sow May 13 – June 9 1 wk after
🥒 Cucumbers Set out May 13 – June 9 1 wk after
🎃 Pumpkins Direct sow May 13 – June 9 1 wk after
🎃 Pumpkins Set out May 13 – June 9 1 wk after
🎃 Summer Squash Direct sow May 13 – June 9 1 wk after
🎃 Summer Squash Set out May 13 – June 9 1 wk after
🌽 Sweet Corn Direct sow May 13 – June 9 1 wk after
🍅 Tomatoes Set out May 13 – June 9 1 wk after
🎃 Winter Squash Direct sow May 13 – June 9 1 wk after
🎃 Winter Squash Set out May 13 – June 9 1 wk after
🥒 Zucchini Direct sow May 13 – June 9 1 wk after
🥒 Zucchini Set out May 13 – June 9 1 wk after
🥒 Cucumbers Direct sow May 20 – June 16 2 wk after
🌶️ Okra Direct sow May 20 – June 16 2 wk after
🌶️ Okra Set out May 20 – June 16 2 wk after
🌶️ Peppers Set out May 20 – June 16 2 wk after
🫘 Southern Peas Direct sow May 20 – June 16 2 wk after
🍠 Sweet Potato Set out May 20 – June 16 2 wk after

Offsets are published guidance; the dates they land on are computed from measured NOAA normals. The seed-starting tool does this for your own ZIP code and counts the days.

What survives the winter changes across Aroostook County

Zone 5a carries 48 of 74 perennial edibles; zone 3b carries 17. The best number is not always the warmest zone — the count peaks in the middle and falls both ways, because the warm end loses plants to insufficient winter chill and summer heat, not to cold.

Hardiness ranges are a judgement, published by growers rather than measured; the zone they are compared against is measured. On a warm-end verdict, check with your local extension service — a coastal zone 8 and an inland zone 8 are not the same summer.

How certain the freeze dates are in Aroostook County Two rows. Each runs from the cautious date, which shortens the growing season, to the optimistic one. The median dates sit between them. Every figure is repeated in the text below this chart. JFMAMJJASONDLast spring freezeFirst fall freeze

Cautious — shortens the seasonMedian across stationsOptimistic

Last spring freeze
Plan to June 21 to be careful. Median May 6 – June 2 across 14 stations; April 25 is the optimistic end.
First fall freeze
Plan to August 29 to be careful. Median September 13 – October 2 across 14 stations; October 17 is the optimistic end.

NOAA publishes these as probabilities, not averages — the middle figure is a median, so half of years fall either side of it. The cautious end is the 10% tail: in roughly nine years in ten the freeze falls on the safe side of it.

The 14 stations behind these numbers

The 14 NOAA stations serving Aroostook County A relative sketch of where the stations sit, about 183 kilometres north to south. Each is named with its NOAA identifier in the station list on this page, which carries the same information as text. ALLAGASH, ME US (USC00170200)BRIDGEWATER, ME US (USC00170833)CARIBOU MUNI AP, ME US (USW00014607)CLAYTON LAKE, ME US (USC00171472)DANFORTH, ME US (USC00171833)FRENCHVILLE AROOSTOOK AP, ME US (USW00004836)FT KENT, ME US (USC00172878)HOULTON 5N, ME US (USC00173944)HOULTON INTL AP, ME US (USW00014609)LIMESTONE 4 NNW, ME US (USW00094645)MILLINOCKET WASTEWATER, ME US (USC00175305)PATTEN 2, ME US (USC00176594)PRESQUE ISLE, ME US (USC00176937)VAN BUREN 2, ME US (USC00178965) ~183 km north to south

All 14 NOAA stations whose normals this page quotes, spanning about 183 km north to south. Every one is named with its identifier in the station list below — this page does not single one out, because no one station speaks for a whole county.

A relative sketch, not a map with a projection: longitude is adjusted for latitude so the shape is not stretched, and there is no basemap. For the one station nearest a specific address, with its real distance, use the ZIP lookup above.

These are the stations this county's ZIP codes actually cite as nearest — not a claim that each one sits inside its boundary, since a rural ZIP legitimately reaches over it. Every figure above comes from them, and each is named so you can check it.

Station NOAA ID Last spring freeze First fall freeze Season
Allagash, ME USC00170200 June 2 September 15 102 days
Bridgewater, ME USC00170833 May 25 September 18 115 days
Caribou Muni AP, ME USW00014607 May 7 October 1 143 days
Clayton Lake, ME USC00171472 May 30 September 13 106 days
Danforth, ME USC00171833 May 25 September 24 119 days
Frenchville Aroostook AP, ME USW00004836 May 6 October 2 147 days
Ft Kent, ME USC00172878 May 23 September 24 121 days
Houlton 5N, ME USC00173944 May 19 September 23 125 days
Houlton INTL AP, ME USW00014609 May 27 September 18 115 days
Limestone 4 Nnw, ME USW00094645 May 16 September 24 129 days
Millinocket Wastewater, ME USC00175305 May 17 September 29 133 days
Patten 2, ME USC00176594 May 13 September 30 138 days
Presque Isle, ME USC00176937 May 14 September 26 131 days
Van Buren 2, ME USC00178965 May 23 September 26 125 days

These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.

Your own ZIP

Work out your own dates

This page describes a whole county. Every tool below answers for one ZIP code, which is the grain the underlying data is published at.

Other places to compare

Aroostook County sits in Maine. That page carries the whole state's zone spread, its metro areas, and every other county in it with a page here.

More of Maine

Gear

If you want to act on this

Each link opens an Amazon search rather than a product we picked. We have not tested these and do not rank them — the search is the honest version, and you choose.

As an Amazon Associate we earn from qualifying purchases. That costs you nothing extra, and it buys no influence over anything on this site: the dates come from NOAA normals and the zones from the USDA, and no product affects either.

Sources

Where these numbers come from

Hardiness zones are the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. Freeze dates and growing-season lengths are NOAA 1991–2020 Climate Normals, taken per station and cited above by name and NOAA ID.

County boundaries come from the Census ZCTA-to-county relation, which is what places each ZIP code — and which treats parishes, boroughs and census areas as county equivalents. No station is chosen to represent this county: every range above is taken across all of them and the count is stated, because picking one would be a judgement dressed as a measurement.