What does USDA hardiness zone 6b mean in Tennessee?

Zone 6b means an average annual extreme minimum winter temperature of −5 to 0 °F — the standard USDA measure of which perennials survive winter. 1 location in Tennessee fall in this zone. It does not set planting dates; see the frost calendar below for that.

When should I plant tomatoes in Tennessee's zone 6b?

Using Roan Mountain's frost dates (this page's median-season location): start seeds indoors about Mar 5 – Mar 19, then transplant outside about May 7 – May 14. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.

Does every location in Tennessee's zone 6b have the same frost dates?

No — they do not all share a weather station, so frost dates vary by a week or more across the 1 locations listed (see the table above for each location's own dates).

USDA zone 6b in Tennessee

−5 to 0 °F avg. annual extreme minimum · 1 location in this group · NOAA 1991–2020 normals

USDA plant hardiness zone 6b covers 1 location across Tennessee (average annual extreme minimum −5 to 0 °F): Roan Mountain, TN. Average last spring frost across this group ranges April 30 and growing seasons run 165 days — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Tennessee location's own frost dates; the printable planting calendar uses Roan Mountain, this group's median-season location.

USDA zone: 6b−5 to 0 °F
Last frost range: Apr 30avg, 32°F
First frost range: Oct 12avg, 32°F
Growing season range: 165days

Locations in this group

Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.

Own frost dates per location.
Location	Also covers	Nearest station	Last frost	First frost	Season (days)
Roan Mountain *	—	Roan Mtn 3sw	Apr 30	Oct 12	165

* Roan Mountain is this group's median-season location — the calendar below is computed from its data.

Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.

Planting calendar (Roan Mountain, representative)

Computed from Roan Mountain's average frost dates — the median-season location in this Tennesseezone 6b group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).

Crop

JanFebMarAprMayJunJulAugSepOctNovDec

Tomato

Pepper

Cucumber

Summer squash / zucchini

Start indoors
Plant out
Fall sowing
First harvest

Planting windows for Roan Mountain (Tennessee, zone 6b), this group's representative location.
Crop	Frost tolerance	Start indoors	Plant out	First harvest	Fall planting	Season fit
Tomato	Tender	Mar 5 – Mar 19	May 7 – May 14	Jul 6 – Jul 26	—	matures comfortably
Pepper	Very tender	Feb 19 – Mar 5	May 14 – May 21	Jul 13 – Aug 12	—	matures comfortably
Cucumber	Tender	Apr 2 – Apr 9	May 7 – May 14	Jun 26 – Jul 16	—	matures comfortably
Summer squash / zucchini	Tender	—	May 7 – May 14	Jun 21 – Jul 6	—	matures comfortably
Bush bean	Tender	—	May 7 – May 14	Jun 26 – Jul 6	Aug 13 – Aug 23	matures comfortably
Sweet corn	Tender	—	Apr 30 – May 14	Jun 29 – Jul 29	—	matures comfortably
Basil	Very tender	Mar 19 – Apr 2	May 7 – May 14	Jun 6 – Jun 21	—	matures comfortably
Lettuce	Half-hardy	Mar 19 – Apr 2	Apr 2 – Apr 16	May 17 – Jun 1	Jul 30 – Aug 14	matures comfortably
Pea	Hardy	—	Mar 19 – Apr 2	May 13 – May 28	Jul 20 – Aug 4	matures comfortably
Spinach	Hardy	—	Mar 19 – Apr 2	Apr 28 – May 8	Aug 9 – Aug 19	matures comfortably
Carrot	Half-hardy	—	Apr 9 – Apr 16	Jun 8 – Jun 28	Jul 10 – Jul 30	matures comfortably
Broccoli	Half-hardy	Mar 5 – Mar 19	Apr 2 – Apr 16	May 27 – Jun 16	Jul 15 – Aug 4	matures comfortably

Which crops fit this growing season

Using Roan Mountain's own 165-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.

Frost & freeze dates (Roan Mountain)

From NOAA's 1991–2020 Climate Normals at station USC00407770. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.

Freeze probabilities by temperature threshold (MM/DD, NOAA 1991–2020), Roan Mountain.
Threshold	Last spring — avg	Last spring — 90%-safe	First fall — avg	First fall — 90%-safe	Season (days)
36°F	May 10	May 24	Oct 3	Oct 15	145
32°F (freeze)	Apr 30	May 16	Oct 12	Oct 25	165
28°F	Apr 20	May 6	Oct 23	Nov 4	185
24°F	Apr 7	Apr 20	Nov 1	Nov 14	207

Growing degree days

Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 1 locations is 2,679; Roan Mountain's own reading is shown below.

Annual growing degree days for Roan Mountain (°F·days, NOAA 1991–2020).
Model	°F·days	Used for
Base 50°F (warm-season)	2,679	standard warm-season base (tomato, corn, beans)
Base 40°F (cool-season)	5,123	cool-season crops (brassicas, greens)

Hardiness zone 6b in Tennessee

Zone 6b means an average annual extreme minimum winter temperature of about −5 to 0 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Tennessee spans 4 hardiness zones in this dataset — see all Tennessee locations for the full range, including zones7a, 7b, 8a.

Explore zone 6b in other states at zone 6b, or see all USDA hardiness zones.

Frequently asked questions

What does USDA hardiness zone 6b mean in Tennessee?: Zone 6b means an average annual extreme minimum winter temperature of −5 to 0 °F — the standard USDA measure of which perennials survive winter. 1 location in Tennessee fall in this zone. It does not set planting dates; see the frost calendar below for that.
When should I plant tomatoes in Tennessee's zone 6b?: Using Roan Mountain's frost dates (this page's median-season location): start seeds indoors about Mar 5 – Mar 19, then transplant outside about May 7 – May 14. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
Does every location in Tennessee's zone 6b have the same frost dates?: No — they do not all share a weather station, so frost dates vary by a week or more across the 1 locations listed (see the table above for each location's own dates).

Sources & method

Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.