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Frost dates and planting calendar for Morristown, Tennessee

Updated October 30, 2026. Based on USDA, NOAA and Colorado State University Extension data. Published by Humblebee.

USDA hardiness zone
7b[1]
Median last spring frost
Apr 10[2]
Median first fall frost
Oct 28[3]
Growing season, median
201 days[4]

Morristown, Tennessee is in USDA hardiness zone 7b on the 2023 map[1]. In half of years the last spring frost comes after April 10, which is the median[2].

Frost dates

JanFebMarAprMayJunJulAugSepOctNovDecLast spring frost: 9 in 10 years after Mar 25, half of years Apr 10, 1 in 10 years after Apr 26Last frostmedian Apr 10First fall frost: 9 in 10 years before Nov 9, half of years Oct 28, 1 in 10 years before Oct 16First frostmedian Oct 28Frost riskHardyHardy vegetables: plant Mar 13 to Mar 27Mar 13 to Mar 27Semi-hardySemi-hardy vegetables: plant Mar 27 to Apr 10Mar 27 to Apr 10TenderTender vegetables: plant around Apr 10around Apr 10Very tenderVery tender vegetables: plant from Apr 24from Apr 24
Shaded: the span between the dates frost passes in 9 of 10 years and 1 of 10 years[2][3]. Green: planting windows from the CSU rules applied to the median last frost (GardenFacts calculation)[6]. Exact dates are in the tables below.

These frost dates are odds from NOAA records for 1991 to 2020, not a forecast[2]. They come from the Morristown Radio Wcrk weather station[5]. In 9 of 10 years the last spring frost comes after March 25, and in 1 of 10 years it comes after April 26[2]. In the fall, the median first frost is October 28[3]. In 1 of 10 years the first frost comes before October 16, and in 9 of 10 years it comes before November 9[3]. Any single year can be earlier or later than these dates[2].

Frost Likely (9 in 10 years) Even odds (5 in 10) Unlikely (1 in 10)
Last spring frost (32°F)[2] after March 25 after April 10 after April 26
First fall frost (32°F)[3] before October 16 before October 28 before November 9
  • Hard freeze (28°F): median last spring date March 29, median first fall date November 6[7].
  • Frost-free growing season: at least 181 days in 9 of 10 years, 201 days in half of years and 221 days in 1 of 10 years[4].
  • The low reached 32°F or colder in 100% of years and 28°F or colder in 100% of years[8].
  • Weather station: Morristown Radio Wcrk (USC00406271), 1.8 miles from the city center, 1,344 feet, 22 years of 1991 to 2020 records[5].

When to plant vegetables

The planting rules come from Colorado State University Extension, and their guide was written for Colorado[6]. We took the NOAA median last frost of April 10 as the average last frost and did the date math for Morristown[6]. Hardy vegetables such as broccoli, lettuce, peas and spinach can go in as early as 2 to 4 weeks before the median last frost, which is March 13 to March 27[6]. Semi-hardy vegetables such as carrots, potatoes and beets can go in as early as 2 weeks before it, from March 27 up to April 10[9]. Tender vegetables such as snap beans, sweet corn and cucumbers can be planted from seed around April 10[10]. Very tender vegetables such as tomatoes, peppers and eggplant typically wait 2 or more weeks after the median last frost, and April 24 is the earliest start[11].

  • Hardy (broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips): as early as 2 to 4 weeks before the median last frost (April 10) is March 13 to March 27[6]
  • Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (April 10) is March 27, up to the median date itself[9]
  • Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, April 10[10]
  • Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (April 10), is April 24[11]
Vegetable (CSU group) Plant from First harvest around
Broccoli (hardy)[12] Mar 13 May 17 (from transplants)
Cabbage (hardy)[12] Mar 13 Jun 6 (from transplants)
Kohlrabi (hardy)[12] Mar 13 May 2
Lettuce (hardy)[12] Mar 13 May 12
Onions (hardy)[12] Mar 13 Jul 1
Peas (hardy)[12] Mar 13 May 17
Radishes (hardy)[12] Mar 13 Apr 12
Spinach (hardy)[12] Mar 13 Apr 22
Turnips (hardy)[12] Mar 13 May 2
Beets (semi-hardy)[12] Mar 27 May 26
Carrots (semi-hardy)[12] Mar 27 Jun 5
Cauliflower (semi-hardy)[12] Mar 27 not listed
Parsnips (semi-hardy)[12] Mar 27 Jun 5
Potatoes (semi-hardy)[12] Mar 27 Jul 30
Swiss chard (semi-hardy)[12] Mar 27 May 26
Snap beans (tender)[12] Apr 10 Jun 9
Sweet corn (tender)[12] Apr 10 Jun 9
Cucumbers (tender)[12] Apr 10 Jun 4
Summer squash (tender)[12] Apr 10 May 30
Cantaloupe (very tender)[12] Apr 24 Jul 18
Eggplant (very tender)[12] Apr 24 Jun 23 (from transplants)
Peppers (very tender)[12] Apr 24 Jul 3 (from transplants)
Tomatoes (very tender)[12] Apr 24 Jun 28 (from transplants)
Winter squash (very tender)[12] Apr 24 Aug 2
Watermelon (very tender)[12] Apr 24 Jul 18
Spacing, depth and soil temperature (CSU Extension)
Vegetable Min. soil temp Depth Spacing Days to harvest
Broccoli[13] 40°F 1/2 in 18 in 65
Cabbage[13] 40°F 1/2 in 18 in 85
Kohlrabi[13] 40°F 1/2 in 7-9 in 50
Lettuce[13] 35°F 1/4 in 7-9 in 60
Onions[13] 35°F 1/4 in (seed), 1-2 in (sets) 4-6 in 110
Peas[13] 40°F 1 in 4-6 in 65
Radishes[13] 40°F 1/2 in 2-3 in 30
Spinach[13] 40°F 1/2 in 4-6 in 40
Turnips[13] 40°F 1/2 in 4-6 in 50
Beets[13] 40°F 3/4-1 in 4-6 in 60
Carrots[13] 40°F 1/4 in 2-3 in 70
Cauliflower[13] 40°F 1/2 in 18 in –
Parsnips[13] 35°F 1/2 in 5-6 in 70
Potatoes[13] 45°F – – 125
Swiss chard[13] 40°F 1 in 7-9 in 60
Snap beans[13] 55°F 1-1 1/2 in 6 in 60
Sweet corn[13] 50°F 1-1 1/2 in 12 x 30 in or 9 x 36 in 60-90
Cucumbers[13] 60°F 1 in 6 in trellised, 24-36 in untrellised 55
Summer squash[13] 60°F 1-1 1/2 in 36-48 in 50
Cantaloupe[13] 60°F 1-1 1/2 in 36-48 in 85
Eggplant[13] 60°F 1/4 in 18-24 in 60
Peppers[13] 60°F 1/4 in 15-18 in 70
Tomatoes[13] 50°F 1/4 in 24 in trellised 65
Winter squash[13] 60°F 1-1 1/2 in 36-48 in 100
Watermelon[13] 60°F 1-1 1/2 in 36-48 in 85

Hardiness zone

Zone 7b means the coldest night of a typical winter is 5°F to 10°F, averaged over 1991 to 2020[1]. The zone is based on winter lows, not on summer heat or frost dates[14]. All of Morristown's land area lies in ZIP code areas rated zone 7b, so the city does not span more than one zone[15].

Zone 7b: average annual extreme minimum temperature 5°F to 10°F (1991 to 2020)[1]. Modeled value at the city center: 7.3°F[1].

Share of the city's land area by ZIP code zone: zone 7b 100%[15].

All towns in zone 7b and what zone 7b means

Zone by ZIP code
ZIP code Zone Coldest night range
37814[15] 7b 5 to 10°F
37813[15] 7b 5 to 10°F
37877[15] 7b 5 to 10°F
37860[15] 7b 5 to 10°F

Questions people ask

What growing zone is Morristown, Tennessee?
The 2023 USDA Plant Hardiness Zone Map puts the center of Morristown in zone 7b[1]. All of the city's land area is in ZIP code areas rated 7b[15].
When is the last frost in Morristown?
In half of years the last spring frost at 32°F comes after April 10, which is the median[2]. In 1 of 10 years it comes after April 26[2].
When to plant tomatoes in Morristown?
CSU Extension says tomatoes typically wait 2 or more weeks after the average last spring frost, and its guide was written for Colorado[11]. Using the median last frost of April 10, the earliest start is April 24[11].
When is the first frost in Morristown?
In half of years the first fall frost at 32°F comes before October 28, which is the median[3]. In 1 of 10 years it comes before October 16[3].
How long is the growing season in Morristown?
The growing season between the last spring and first fall frost is at least 201 days in half of years[4]. It is at least 181 days in 9 of 10 years[4].

Facts and sources

  1. The 2023 USDA Plant Hardiness Zone Map puts the center of Morristown, Tennessee in zone 7b. Zone 7b means an average annual extreme minimum temperature of 5°F to 10°F over 1991 to 2020. The map's modeled value at the city center is 7.3°F. USDA zone map 2023 (PRISM, OSU)
  2. Last spring frost (32°F) at this station: in 9 of 10 years the last frost comes after March 25, in half of years after April 10, and in 1 of 10 years after April 26 (NOAA 1991 to 2020 normals). The median last frost date is April 10. NOAA Climate Normals 1991-2020
  3. First fall frost (32°F) at this station: in 1 of 10 years the first frost comes before October 16, in half of years before October 28, and in 9 of 10 years before November 9 (NOAA 1991 to 2020 normals). The median first frost date is October 28. NOAA Climate Normals 1991-2020
  4. Growing season (days between the last spring and first fall 32°F frost) at this station: at least 181 days in 9 of 10 years, at least 201 days in half of years, and at least 221 days in 1 of 10 years. NOAA Climate Normals 1991-2020
  5. Frost dates on this page come from NOAA climate normals for the Morristown Radio Wcrk weather station (USC00406271), 1.8 miles from the center of Morristown at 1,344 feet, using 22 years of records from 1991 to 2020. NOAA Climate Normals 1991-2020
  6. Colorado State University Extension's vegetable planting guide (written for Colorado) groups broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips as hardy vegetables, with this rule: as early as 2-4 weeks before the average last... CSU Extension GardenNotes #720
  7. Hard freeze (28°F) at this station: the median last spring date is March 29 and the median first fall date is November 6. NOAA Climate Normals 1991-2020
  8. At this station the low reached 32°F or colder in 100% of years from 1991 to 2020, and 28°F or colder in 100% of years. NOAA Climate Normals 1991-2020
  9. Colorado State University Extension's vegetable planting guide (written for Colorado) groups beets, carrots, cauliflower, parsnips, potatoes, Swiss chard as semi-hardy vegetables, with this rule: as early as 0-2 weeks before the average last spring frost.... CSU Extension GardenNotes #720
  10. Colorado State University Extension's vegetable planting guide (written for Colorado) groups snap beans, sweet corn, cucumbers, summer squash as tender vegetables, with this rule: from seed around the average last spring frost; cucumber and summer squash... CSU Extension GardenNotes #720
  11. Colorado State University Extension's vegetable planting guide (written for Colorado) groups cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon as very tender vegetables, with this rule: typically 2 or more weeks after the average last... CSU Extension GardenNotes #720
  12. GardenFacts calculation: earliest planting date plus CSU days to harvest (table on this page), from the station's median last frost. NOAA Climate Normals 1991-2020
  13. CSU Extension vegetable table: soil temperature, depth, spacing, days to harvest (table on this page). CSU Extension GardenNotes #720
  14. USDA hardiness zones are based on the average annual extreme minimum winter temperature (the coldest night of each winter, averaged over 1991 to 2020 for the 2023 map), not on summer heat or frost dates. Each zone spans 10°F and each half zone (a or b)... USDA Plant Hardiness Zone Map
  15. Morristown, Tennessee overlaps 4 ZIP code areas. By land area, 100% lies in ZIP code areas rated zone 7b. USDA zone map 2023 (PRISM, OSU)

Frost dates are probabilities from 1991 to 2020 weather records at one NOAA station, not a forecast. Any year can be earlier or later. The hardiness zone describes the average coldest winter night, not frost dates or summer heat. Spots inside the city can differ (ZIP table). Planting rules come from Colorado State University Extension's guide, written for Colorado. A local extension office may give dates tuned to the area. Planting and harvest dates marked GardenFacts calculation are simple arithmetic from the facts above, not advice from the source.

Hardiness zone data: USDA Plant Hardiness Zone Map (2023), USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu, accessed October 30, 2026. This is not the official USDA map. Frost data: NOAA NCEI U.S. Climate Normals 1991-2020. Planting rules: Colorado State University Extension.