Metro areas

Gardening in Birmingham, AL

This metro spans USDA zones 8a to 8b, so there is no single zone for Birmingham, AL and anyone who gives you one is rounding. 76% of its ZIP codes are zone 8a; the rest are not.

USDA zones 8a–8b 2 zones across 119 ZIP codes
ZIP codes 119 119 have a NOAA station within range
Weather stations 17 NOAA 1991–2020 normals, across 5,280 sq mi

Which zone you are in depends where you are

Birmingham, AL covers 2 hardiness zones. A guide that gives the metro one zone has picked whichever is largest and rounded everyone else into it — which is fine for the 76% in zone 8a and wrong for the other 24%. Here is the actual split.

Zone ZIP codes Share  
8a 90 76%
8b 29 24%

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 8 – April 6
First fall freeze October 29 – November 18

Those are the earliest and latest medians among the 17 stations serving this metro — 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 — a zone is the average annual coldest night, a freeze date is when the season turns — 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 17 stations serving Birmingham, AL it runs 205–254 days . That figure is published, not computed from the two freeze dates — subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 87–92 °F , at or above the 90 °F point where cool-season crops bolt and tomato and pepper pollen fails — so midsummer sowings of lettuce and its relatives are worth holding here.

When to start seeds in Birmingham, AL

Every spring job for 63 crop dates, counted from this metro's own last spring freeze. Each is a range across all 17 stations — the earliest and latest that job falls anywhere in the metro — because no one station speaks for the whole area.

Crop Job When Offset
Green Onions Start indoors January 11 – February 9 8 weeks before
Peppers Start indoors January 11 – February 9 8 weeks before
Broccoli Start indoors January 25 – February 23 6 weeks before
Cabbage Start indoors January 25 – February 23 6 weeks before
Collards Start indoors January 25 – February 23 6 weeks before
Kale Start indoors January 25 – February 23 6 weeks before
Leaf Lettuce Start indoors January 25 – February 23 6 weeks before
Peas Direct sow January 25 – February 23 6 weeks before
Spinach Direct sow January 25 – February 23 6 weeks before
Sweet Potato Start indoors January 25 – February 23 6 weeks before
Tomatoes Start indoors January 25 – February 23 6 weeks before
Bok Choy Start indoors February 1 – March 2 5 weeks before
Kohlrabi Start indoors February 1 – March 2 5 weeks before
Swiss Chard Start indoors February 1 – March 2 5 weeks before
Arugula Direct sow February 8 – March 9 4 weeks before
Baby Salad Greens Direct sow February 8 – March 9 4 weeks before
Beets Direct sow February 8 – March 9 4 weeks before
Green Onions Direct sow February 8 – March 9 4 weeks before
Mustard Greens Direct sow February 8 – March 9 4 weeks before
Okra Start indoors February 8 – March 9 4 weeks before
Radishes Direct sow February 8 – March 9 4 weeks before
Turnips Direct sow February 8 – March 9 4 weeks before
Cabbage Set out February 15 – March 16 3 weeks before
Carrots Direct sow February 15 – March 16 3 weeks before
Collards Direct sow February 15 – March 16 3 weeks before
Collards Set out February 15 – March 16 3 weeks before
Cucumbers Start indoors February 15 – March 16 3 weeks before
Green Onions Set out February 15 – March 16 3 weeks before
Kale Direct sow February 15 – March 16 3 weeks before
Kale Set out February 15 – March 16 3 weeks before
Kohlrabi Direct sow February 15 – March 16 3 weeks before
Kohlrabi Set out February 15 – March 16 3 weeks before
Leaf Lettuce Direct sow February 15 – March 16 3 weeks before
Pumpkins Start indoors February 15 – March 16 3 weeks before
Summer Squash Start indoors February 15 – March 16 3 weeks before
Winter Squash Start indoors February 15 – March 16 3 weeks before
Zucchini Start indoors February 15 – March 16 3 weeks before
Bok Choy Direct sow February 22 – March 23 2 weeks before
Bok Choy Set out February 22 – March 23 2 weeks before
Broccoli Set out February 22 – March 23 2 weeks before
Cilantro Direct sow February 22 – March 23 2 weeks before
Leaf Lettuce Set out February 22 – March 23 2 weeks before
Swiss Chard Direct sow February 22 – March 23 2 weeks before
Swiss Chard Set out February 22 – March 23 2 weeks before
Dill Direct sow March 1 – March 30 1 week before
Bush Beans Direct sow March 15 – April 13 1 week after
Cucumbers Set out March 15 – April 13 1 week after
Pumpkins Direct sow March 15 – April 13 1 week after
Pumpkins Set out March 15 – April 13 1 week after
Summer Squash Direct sow March 15 – April 13 1 week after
Summer Squash Set out March 15 – April 13 1 week after
Sweet Corn Direct sow March 15 – April 13 1 week after
Tomatoes Set out March 15 – April 13 1 week after
Winter Squash Direct sow March 15 – April 13 1 week after
Winter Squash Set out March 15 – April 13 1 week after
Zucchini Direct sow March 15 – April 13 1 week after
Zucchini Set out March 15 – April 13 1 week after
Cucumbers Direct sow March 22 – April 20 2 weeks after
Okra Direct sow March 22 – April 20 2 weeks after
Okra Set out March 22 – April 20 2 weeks after
Peppers Set out March 22 – April 20 2 weeks after
Southern Peas Direct sow March 22 – April 20 2 weeks after
Sweet Potato Set out March 22 – April 20 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 Birmingham, AL

Of 74 perennial fruits, nuts, berries, vegetables and herbs, 57 come through the winter in zone 8a and only 54 in zone 8b. That is a different garden at each end of the same metro.

Zone ZIPs Survive Fail for being too warm
8a 90 57 of 74 8
8b 29 54 of 74 11

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 °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.

The 17 stations behind these numbers

Every figure above comes from these, and each is named so you can check it. Distances vary by ZIP code, so the tools report yours rather than this page guessing.

Station NOAA ID Last spring freeze First fall freeze Season
Alabaster Shelby Co AP, AL USW00053864 March 12 November 16 248 days
Bankhead L&D, AL USC00010505 March 20 November 11 235 days
Bessemer 3 Wsw, AL USC00010764 March 23 November 10 231 days
Birmingham AP, AL USW00013876 March 21 November 11 236 days
Centreville 6 SW, AL USW00003881 April 2 November 2 215 days
Childersburg Wtp, AL USC00011620 March 31 November 2 216 days
Clanton 2 NE, AL USW00063891 March 22 November 10 237 days
Clanton, AL USC00011694 March 24 November 10 233 days
Hanceville, AL USC00013655 April 6 October 29 205 days
Helena, AL USC00013781 March 19 November 8 236 days
Jasper, AL USC00014226 March 30 November 4 220 days
Oneonta, AL USC00016121 March 26 November 10 230 days
Pinson, AL USC00016478 April 4 November 1 212 days
Selma, AL USC00017366 March 8 November 18 254 days
Talladega 10 Nne, AL USW00073803 March 26 November 4 225 days
Talladega, AL USC00018024 April 5 November 1 208 days
Thorsby Exp Stn, AL USC00018209 March 21 November 11 235 days

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

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.

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.

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