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Place guide

Planting zones in Huntsville, AL

This metro spans USDA zones 7b to 8a, so there is no single zone for Huntsville, AL and anyone who gives you one is rounding. 81% of its ZIP codes are zone 8a; the rest are not.

USDA zones 7b–8a 2 zones across 32 ZIP codes
ZIP codes 32 32 have a NOAA station within range
Weather stations 8 NOAA 1991–2020 normals, across 1,365 sq mi

Your ZIP code

Get the exact answer for your address

Everything above describes Huntsville, AL as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact β€” 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.

Huntsville, AL does not have one planting answer

Its own weather stations disagree about 12 of the 32 crops in this table right now, so any single list would be wrong for part of the metro area. That is not a gap in the data β€” it is what the data says.

Shortest season
201 days
FAYETTEVILLE WTP, TN US (USC00403074)
Longest season
238 days
ATHENS, AL US (USC00010390)

37 days of growing season separate those two stations, and both serve ZIP codes in Huntsville, AL. The ZIP lookup above answers for one address instead of averaging a place that has no average.

Why the hardiness zone does not settle this

A USDA zone is a winter-minimum statistic. It was never a growing-season one, and it does not behave like one: within a single zone the growing season runs a median 54 days wider at the 10th–90th percentile, and annual growing degree days vary by 2.02Γ—.

The zones also overlap rather than stack β€” 30% of zone 6b freezes before the median zone 6a station. The zone tells you what survives your winter; the station tells you what finishes before your autumn.

The whole dataset behind that β†’

Growing season across Huntsville, AL A one-year bar. Every one of the 8 NOAA stations serving this metro area counts April 7 to October 28 as growing season, 204 days. At least one counts March 20 to November 12, 237 days. The same figures are written out below this chart. JFMAMJJASONDApril 7October 28

All 8 stations agreeAt least one station

Every one of the 8 NOAA stations serving this metro area counts April 7 – October 28 as growing season (204 days). Widening to any single station gives March 20 – November 12 (237 days).

That is a 33-day difference inside one metro area β€” 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

Huntsville, AL covers 2 hardiness zones. A guide that gives the metro one zone has picked whichever is largest and rounded everyone else into it β€” which is fine for the 81% in zone 8a and wrong for the other 19%. Here is the actual split.

Zone ZIP codes Share  
8a 26 81%
7b 6 19%

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

Your freeze dates

Last spring freeze March 20 – April 7
First fall freeze October 28 – November 12

Those are the earliest and latest medians among the 8 stations serving this metro β€” not an average, and not one station standing in for the rest. Half of years freeze later than a station's own median.

The spread is the point. Even in a metro that is one hardiness zone throughout, its stations disagree about the last spring freeze. Hardiness zone and frost date measure different things β€” a zone is the average annual coldest night, a freeze date is when the season turns β€” and a place can be uniform in one and varied in the other. Use the tools below with your own ZIP rather than the ends of this range.

Your growing season

NOAA publishes a growing-season length for each station, and across the 8 stations serving Huntsville, AL it runs 201–238 days . That figure is published, not computed from the two freeze dates β€” subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 87–91 Β°F , at or above the 90 Β°F point where cool-season crops bolt and tomato and pepper pollen fails β€” so midsummer sowings of lettuce and its relatives are worth holding here. Summer rain over the same months runs 10.7–14.0" across those 8 stations, against the rough inch a week β€” about 13 inches over the same 92 days β€” that a vegetable garden is usually reckoned to want. The middle station covers about 95% 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 89 Β°F summer afternoon drying the soil faster than a cool one.

When to start seeds in Huntsville, AL

Every spring job for 63 crop dates, counted from this metro's own last spring freeze. Each is a range across all 8 stations β€” the earliest and latest that job falls anywhere in the metro β€” because no one station speaks for the whole area.

Crop Job When Offset
Green Onions Start indoors January 23 – February 10 8 weeks before
Peppers Start indoors January 23 – February 10 8 weeks before
Broccoli Start indoors February 6 – February 24 6 weeks before
Cabbage Start indoors February 6 – February 24 6 weeks before
Collards Start indoors February 6 – February 24 6 weeks before
Kale Start indoors February 6 – February 24 6 weeks before
Leaf Lettuce Start indoors February 6 – February 24 6 weeks before
Peas Direct sow February 6 – February 24 6 weeks before
Spinach Direct sow February 6 – February 24 6 weeks before
Sweet Potato Start indoors February 6 – February 24 6 weeks before
Tomatoes Start indoors February 6 – February 24 6 weeks before
Bok Choy Start indoors February 13 – March 3 5 weeks before
Kohlrabi Start indoors February 13 – March 3 5 weeks before
Swiss Chard Start indoors February 13 – March 3 5 weeks before
Arugula Direct sow February 20 – March 10 4 weeks before
Baby Salad Greens Direct sow February 20 – March 10 4 weeks before
Beets Direct sow February 20 – March 10 4 weeks before
Green Onions Direct sow February 20 – March 10 4 weeks before
Mustard Greens Direct sow February 20 – March 10 4 weeks before
Okra Start indoors February 20 – March 10 4 weeks before
Radishes Direct sow February 20 – March 10 4 weeks before
Turnips Direct sow February 20 – March 10 4 weeks before
Cabbage Set out February 27 – March 17 3 weeks before
Carrots Direct sow February 27 – March 17 3 weeks before
Collards Direct sow February 27 – March 17 3 weeks before
Collards Set out February 27 – March 17 3 weeks before
Cucumbers Start indoors February 27 – March 17 3 weeks before
Green Onions Set out February 27 – March 17 3 weeks before
Kale Direct sow February 27 – March 17 3 weeks before
Kale Set out February 27 – March 17 3 weeks before
Kohlrabi Direct sow February 27 – March 17 3 weeks before
Kohlrabi Set out February 27 – March 17 3 weeks before
Leaf Lettuce Direct sow February 27 – March 17 3 weeks before
Pumpkins Start indoors February 27 – March 17 3 weeks before
Summer Squash Start indoors February 27 – March 17 3 weeks before
Winter Squash Start indoors February 27 – March 17 3 weeks before
Zucchini Start indoors February 27 – March 17 3 weeks before
Bok Choy Direct sow March 6 – March 24 2 weeks before
Bok Choy Set out March 6 – March 24 2 weeks before
Broccoli Set out March 6 – March 24 2 weeks before
Cilantro Direct sow March 6 – March 24 2 weeks before
Leaf Lettuce Set out March 6 – March 24 2 weeks before
Swiss Chard Direct sow March 6 – March 24 2 weeks before
Swiss Chard Set out March 6 – March 24 2 weeks before
Dill Direct sow March 13 – March 31 1 week before
Bush Beans Direct sow March 27 – April 14 1 week after
Cucumbers Set out March 27 – April 14 1 week after
Pumpkins Direct sow March 27 – April 14 1 week after
Pumpkins Set out March 27 – April 14 1 week after
Summer Squash Direct sow March 27 – April 14 1 week after
Summer Squash Set out March 27 – April 14 1 week after
Sweet Corn Direct sow March 27 – April 14 1 week after
Tomatoes Set out March 27 – April 14 1 week after
Winter Squash Direct sow March 27 – April 14 1 week after
Winter Squash Set out March 27 – April 14 1 week after
Zucchini Direct sow March 27 – April 14 1 week after
Zucchini Set out March 27 – April 14 1 week after
Cucumbers Direct sow April 3 – April 21 2 weeks after
Okra Direct sow April 3 – April 21 2 weeks after
Okra Set out April 3 – April 21 2 weeks after
Peppers Set out April 3 – April 21 2 weeks after
Southern Peas Direct sow April 3 – April 21 2 weeks after
Sweet Potato Set out April 3 – April 21 2 weeks after

The week offsets are conventional extension guidance and vary by variety; the freeze dates they are counted from are measured. For a single date rather than a range, run when do I start my seeds? with your own ZIP code.

What survives the winter changes across Huntsville, AL

Of 74 perennial fruits, nuts, berries, vegetables and herbs, 57 come through the winter in zone 8a and only 56 in zone 7b. That is a different garden at each end of the same metro.

Zone ZIPs Survive Fail for being too warm
7b 6 56 of 74 3
8a 26 57 of 74 8

The last column is the counterintuitive one, and it is why the totals do not simply rise as the winters get milder. Most temperate fruit needs a documented number of hours below about 45 Β°F to break dormancy and set a crop, so an apple fails in a winter that is too warm; currants and rhubarb cook in the summer heat that comes with it. See the full list with reasons.

How certain the freeze dates are in Huntsville, AL 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 β€” shortens the seasonMedian across stationsOptimistic

Last spring freeze
Plan to April 22 to be careful. Median March 20 – April 7 across 8 stations; March 1 is the optimistic end.
First fall freeze
Plan to October 13 to be careful. Median October 28 – November 12 across 8 stations; December 1 is the optimistic end.

NOAA publishes these as probabilities, not averages β€” 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 8 stations behind these numbers

The 8 NOAA stations serving Huntsville, AL A relative sketch of where the stations sit, about 65 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. ARDMORE, TN US (USC00400235)ATHENS, AL US (USC00010390)BELLE MINA 2 N, AL US (USC00010655)DECATUR PRYOR FLD, AL US (USW00053852)FAYETTEVILLE WTP, TN US (USC00403074)HUNTSVILLE INTL AP, AL US (USW00003856)LEXINGTON, AL US (USC00010260)OWENS CROSS ROADS 3S, AL US (USC00016196) ~65 km north to south

All 8 NOAA stations whose normals this page quotes, spanning about 65 km north to south. Every one is named with its identifier in the station list below β€” this page does not single one out, because no one station speaks for a whole metro area.

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.

Every figure above comes from these, and each is named so you can check it. Which station serves a given ZIP code, and how far away it is, varies across the metro β€” the table below gives it per ZIP code rather than this page averaging it.

Station NOAA ID Last spring freeze First fall freeze Season
Ardmore, TN USC00400235 March 30 November 4 223 days
Athens, AL USC00010390 March 20 November 12 238 days
Belle Mina 2 N, AL USC00010655 March 31 November 1 214 days
Decatur Pryor FLD, AL USW00053852 March 27 November 3 221 days
Fayetteville Wtp, TN USC00403074 April 7 October 28 201 days
Huntsville INTL AP, AL USW00003856 March 24 November 8 229 days
Lexington, AL USC00010260 March 29 November 4 219 days
Owens Cross Roads 3S, AL USC00016196 April 4 October 30 210 days

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

Every ZIP code in Huntsville, AL

Zones are published per ZIP code, not per metro area, so this is the exact answer rather than the metro area's average. The station column is the nearest one to that ZIP code's centroid and how far away it is β€” 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
35611 8a Athens, AL 12.2 km
35613 8a Athens, AL 8.0 km
35614 8a Athens, AL 15.0 km
35615 8a Belle Mina 2 N, AL 3.0 km
35620 7b Ardmore, TN 16.5 km
35647 7b Lexington, AL 23.2 km
35649 8a Belle Mina 2 N, AL 7.2 km
35671 8a Decatur Pryor FLD, AL 1.9 km
35739 7b Ardmore, TN 6.5 km
35741 8a Owens Cross Roads 3S, AL 19.7 km
35748 8a Owens Cross Roads 3S, AL 20.2 km
35749 8a Athens, AL 18.4 km
35750 7b Fayetteville Wtp, TN 20.3 km
35756 8a Huntsville INTL AP, AL 2.9 km
35757 8a Huntsville INTL AP, AL 16.1 km
35758 8a Huntsville INTL AP, AL 8.3 km
35759 8a Fayetteville Wtp, TN 29.6 km
35760 8a Owens Cross Roads 3S, AL 5.7 km
35761 7b Fayetteville Wtp, TN 27.7 km
35763 8a Owens Cross Roads 3S, AL 7.0 km
35773 7b Ardmore, TN 17.6 km
35801 8a Owens Cross Roads 3S, AL 22.1 km
35802 8a Owens Cross Roads 3S, AL 17.0 km
35803 8a Owens Cross Roads 3S, AL 6.9 km
35805 8a Huntsville INTL AP, AL 16.6 km
35806 8a Huntsville INTL AP, AL 16.5 km
35808 8a Huntsville INTL AP, AL 12.0 km
35810 8a Huntsville INTL AP, AL 24.3 km
35811 8a Owens Cross Roads 3S, AL 27.9 km
35816 8a Huntsville INTL AP, AL 17.6 km
35824 8a Huntsville INTL AP, AL 3.1 km
35896 8a Huntsville INTL AP, AL 17.3 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.

Your own ZIP

Work out your own dates

Each of these takes a ZIP code and answers for that ZIP alone, citing the station it used and how far away it is. There is a ZIP box in the header of every page.

Other places to compare

These metros span exactly the same zones β€” 7b–8a β€” so the same plants are in and out of range across them. The freeze dates and the spring calendar are their own.

Gardening in Alabama β€” zones 7b– 9b covers the whole state: how its 652 ZIP codes divide between 5 hardiness zones, and the freeze dates across every NOAA station in it.

Other metro areas in AL:

All 388 metro areas, by state

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 β€” 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

The hardiness zone is the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. The freeze dates are NOAA's 1991–2020 Climate Normals, read from every station whose normals cover a ZIP code in this metro. Nothing here is estimated, and no station stands in for another.

This page names no single station on purpose. Picking one to represent a metro sounds reasonable and is not: the station serving the most ZIP codes is an artifact of where ZIP centroids happen to fall, and it selects a lock on the Monongahela for Pittsburgh and a far southern suburb for Chicago. A range across every station is true; a single cited date for a whole metro is not.

All metro areas