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Frost dates and planting calendar for Bloomington, Indiana

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

USDA hardiness zone
6b[1]
Median last spring frost
Apr 15[2]
Median first fall frost
Oct 26[3]
Growing season, median
192 days[4]

Bloomington, Indiana is in USDA hardiness zone 6b[1]. The median last spring frost is April 15, which means that in half of years the last frost comes after that date[2].

Frost dates

JanFebMarAprMayJunJulAugSepOctNovDecLast spring frost: 9 in 10 years after Mar 31, half of years Apr 15, 1 in 10 years after May 3Last frostmedian Apr 15First fall frost: 9 in 10 years before Nov 9, half of years Oct 26, 1 in 10 years before Oct 11First frostmedian Oct 26Frost riskHardyHardy vegetables: plant Mar 18 to Apr 1Mar 18 to Apr 1Semi-hardySemi-hardy vegetables: plant Apr 1 to Apr 15Apr 1 to Apr 15TenderTender vegetables: plant around Apr 15around Apr 15Very tenderVery tender vegetables: plant from Apr 29from Apr 29
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 come from NOAA climate normals for the Bloomington Indiana Univ weather station, using records from 1991 to 2020[5]. They are chances, not promises. In 9 of 10 years the last spring frost comes after March 31, and in 1 of 10 years it comes after May 3[2]. In the fall, the median first frost is October 26[3]. In 1 of 10 years the first frost comes before October 11[3]. The growing season is at least 192 days in half of years[4].

Frost Likely (9 in 10 years) Even odds (5 in 10) Unlikely (1 in 10)
Last spring frost (32°F)[2] after March 31 after April 15 after May 3
First fall frost (32°F)[3] before October 11 before October 26 before November 9
  • Hard freeze (28°F): median last spring date April 2, median first fall date November 4[7].
  • Frost-free growing season: at least 169 days in 9 of 10 years, 192 days in half of years and 214 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: Bloomington Indiana Univ (USC00120784), 0.7 miles from the city center, 830 feet, 28 years of 1991 to 2020 records[5].

When to plant vegetables

Colorado State University Extension groups vegetables by how well they handle cold. Its guide was written for Colorado[6]. GardenFacts used the median last frost, April 15[2], to turn those rules into dates for Bloomington[6]. Hardy vegetables such as broccoli, lettuce, peas and spinach can go in as early as 2 to 4 weeks before that date, which is March 18 to April 1[6]. Semi-hardy vegetables such as carrots, potatoes and beets can go in as early as April 1[9]. Tender vegetables such as snap beans and sweet corn can be sown from seed around April 15[10]. Very tender vegetables such as tomatoes and peppers typically wait 2 or more weeks after the median last frost, so the earliest start is April 29[11].

  • Hardy (broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips): as early as 2 to 4 weeks before the median last frost (April 15) is March 18 to April 1[6]
  • Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (April 15) is April 1, up to the median date itself[9]
  • Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, April 15[10]
  • Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (April 15), is April 29[11]
Vegetable (CSU group) Plant from First harvest around
Broccoli (hardy)[12] Mar 18 May 22 (from transplants)
Cabbage (hardy)[12] Mar 18 Jun 11 (from transplants)
Kohlrabi (hardy)[12] Mar 18 May 7
Lettuce (hardy)[12] Mar 18 May 17
Onions (hardy)[12] Mar 18 Jul 6
Peas (hardy)[12] Mar 18 May 22
Radishes (hardy)[12] Mar 18 Apr 17
Spinach (hardy)[12] Mar 18 Apr 27
Turnips (hardy)[12] Mar 18 May 7
Beets (semi-hardy)[12] Apr 1 May 31
Carrots (semi-hardy)[12] Apr 1 Jun 10
Cauliflower (semi-hardy)[12] Apr 1 not listed
Parsnips (semi-hardy)[12] Apr 1 Jun 10
Potatoes (semi-hardy)[12] Apr 1 Aug 4
Swiss chard (semi-hardy)[12] Apr 1 May 31
Snap beans (tender)[12] Apr 15 Jun 14
Sweet corn (tender)[12] Apr 15 Jun 14
Cucumbers (tender)[12] Apr 15 Jun 9
Summer squash (tender)[12] Apr 15 Jun 4
Cantaloupe (very tender)[12] Apr 29 Jul 23
Eggplant (very tender)[12] Apr 29 Jun 28 (from transplants)
Peppers (very tender)[12] Apr 29 Jul 8 (from transplants)
Tomatoes (very tender)[12] Apr 29 Jul 3 (from transplants)
Winter squash (very tender)[12] Apr 29 Aug 7
Watermelon (very tender)[12] Apr 29 Jul 23
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 6b means an average yearly coldest night of -5°F to 0°F over 1991 to 2020[1]. The zone is based on winter lows, not on frost dates[14]. All 6 ZIP code areas that overlap Bloomington are rated zone 6b by land area[15].

Zone 6b: average annual extreme minimum temperature -5°F to 0°F (1991 to 2020)[1]. Modeled value at the city center: -3.7°F[1].

Share of the city's land area by ZIP code zone: zone 6b 100%[15].

All towns in zone 6b and what zone 6b means

Zone by ZIP code
ZIP code Zone Coldest night range
47401[15] 6b -5 to 0°F
47408[15] 6b -5 to 0°F
47403[15] 6b -5 to 0°F
47404[15] 6b -5 to 0°F
47406[15] 6b -5 to 0°F
47405[15] 6b -5 to 0°F

Questions people ask

What growing zone is Bloomington, Indiana?
The 2023 USDA map puts the center of Bloomington in zone 6b[1]. All of the city's land area lies in ZIP code areas rated 6b[15].
When is the last frost in Bloomington?
The median last spring frost is April 15, so in half of years the last frost comes after that date[2]. In 1 of 10 years it comes after May 3[2].
When to plant tomatoes in Bloomington?
CSU Extension says tomatoes typically go in 2 or more weeks after the average last frost[11]. Using the median last frost, the earliest start is April 29[11].
When is the first frost in Bloomington?
The median first fall frost is October 26[3]. In 1 of 10 years it comes before October 11[3].
How long is the growing season in Bloomington?
The season between the last and first frost is at least 192 days in half of years[4]. It is at least 169 days in 9 of 10 years[4].

Facts and sources

  1. The 2023 USDA Plant Hardiness Zone Map puts the center of Bloomington, Indiana in zone 6b. Zone 6b means an average annual extreme minimum temperature of -5°F to 0°F over 1991 to 2020. The map's modeled value at the city center is minus 3.7°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 31, in half of years after April 15, and in 1 of 10 years after May 3 (NOAA 1991 to 2020 normals). The median last frost date is April 15. 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 11, in half of years before October 26, and in 9 of 10 years before November 9 (NOAA 1991 to 2020 normals). The median first frost date is October 26. NOAA Climate Normals 1991-2020
  4. Growing season (days between the last spring and first fall 32°F frost) at this station: at least 169 days in 9 of 10 years, at least 192 days in half of years, and at least 214 days in 1 of 10 years. NOAA Climate Normals 1991-2020
  5. Frost dates on this page come from NOAA climate normals for the Bloomington Indiana Univ weather station (USC00120784), 0.7 miles from the center of Bloomington at 830 feet, using 28 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 April 2 and the median first fall date is November 4. 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. Bloomington, Indiana overlaps 6 ZIP code areas. By land area, 100% lies in ZIP code areas rated zone 6b. 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.