Knowing when to plant for your area of Illinois and starting your plants right will help maximize the growing season. Download printable infosheets handy for using on the go or in the garden or explore below.
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When to Plant in Illinois Cuándo Debes Sembrar el Jardín en Illinois
Planting dates are determined by the first and last frost dates as well as how long it takes for a crop to mature. There is also a difference for cool- and warm-season crops.
- Cool-season crops grow and develop best in early spring or fall temperatures. Some cool-season crops can withstand a frost without damage, and some are even improved by experiencing a light frost. Examples: Carrots, broccoli, turnip, and radish.
- Warm-season crops do not grow well in lower temperatures and must be planted well after the average last frost date. Examples: Tomato, peppers, winter squash, and cucumber.
Illinois Frost-Free Dates
Spring frost-free dates vary year to year. The Illinois State Water Survey and Illinois State Climatologist have frost maps with temperature data from 1991 to 2020. The spring maps are for the first and last dates of the last 32-degree frosts and 28-degree hard freezes, as well as the median date, and last freezes for 1 and 9 years out of 10 years. Fall frost dates are also available for gardeners who grow cool-season vegetables.
Gardeners can examine the maps to determine when it is right for them to plant.
Regional spring last frost dates
The following spring frost-free dates are a general guide for regions of Illinois. These are the median dates for when the last 32-degree freeze occurred. Last freezes have occurred both before and after these time periods.
- Northern Illinois: April 8-29
- Central Illinois: April 8-15
- Southern Illinois: April 1-8
Southern Illinois’ longer growing season means gardeners there can generally start their crops two weeks earlier than central Illinois. They also can typically harvest for about two weeks longer. Northern Illinois has a shorter growing season and can plant about two weeks later than Central Illinois. Always review plant tags and seed packets for recommendations.
Determining spring frost-free dates
Use the frost dates maps to determine the earliest and latest freezes in your area. For example, the data for Macon County in central Illinois outlined below would lead a cautious gardener or a gardener with only warm-season plants to plant outside in mid-May. A common guideline for that region is that it is safe to plant after Mother's Day. A gardener who may want more growing days may take a chance and start planting outside in mid-April, or if they are planting cool-season crops that can handle frost, they may plant in mid-March.
Macon County's last spring freeze dates
The last 32-degree frosts
- Earliest last freeze: March 19-24 / Latest last freeze: May 5-15 / Median last freeze: April 8-15
- 9 out of 10 years: April 22-29 / 1 out of 10 years: March 25-April 1
The last 28-degree hard freezes
- Earliest last freeze: March 6-11 / Latest last freeze: April 15-25 / Median last freeze: March 26-April 5
- 9 out of 10 years: April 10-15 / 1 out of 10 years: March 16-21
Plant Hardiness Zones
The U.S. Department of Agriculture provides a national Hardiness Zone map with 13 zones to help gardeners and growers better understand and choose which perennial plants will survive a region's winter and thrive long-term. With a few exceptions, most fruit and vegetable plants in Illinois are annuals, so the zones mostly apply to landscape plants.
From top to tip, Illinois is almost 400 miles long and has three hardiness zones and six subzones: 5a, 5b, 6a, 6b, 7a, and 7b. Due to the urban heat effect, the Chicago area has a warmer zone than the rest of northern Illinois.
Crop Maturity
When to plant also depends on how long it takes a crop to mature. Always review plant tags and seed packets for how long it takes to harvest produce from the plant.
Northern Illinois has a shorter growing season than southern Illinois. The average length of the growing season varies from 215 days in far southern Illinois to 180 days in far northern Illinois and the State Climatologist website also provides a Growing Season Length map.
Illinois Fruit and Vegetable Planting Dates
The following chart covers suggested date ranges to plant vegetable seeds or transplants outside in northern, central, and southern Illinois. Always confirm plant dates with the seed packet or plant tag.
When there are two dates, the crop can be planted and harvested twice for both a summer and fall crop.
Planting Dates for Common Vegetables
Asparagus from Crowns
Northern Illinois: April 1 to 30 | Central Illinois: March 15 to April 15 | Southern Illinois: March 1 to April 1
Sow 12 to 18 inches apart and 6 inches deep. Spread roots and cover crown bud with 2 inches of soil; do not harvest first year; mow foliage after fall frost.
Bush Beans from Seed
Northern Illinois: May 24 to June 30 or July 30 to Aug. 14 | Central Illinois: May 10 to June 15 or July 15 to 30 | Southern Illinois: April 26 to June 1, July 1 to July 15
Sow 2-4 inches apart and 1 inch deep.
Pole Beans from Seed
Northern Illinois: May 24 to June 30 | Central Illinois: May 10 to June 15 | Southern Illinois: April 26 to June 1
Sow 4-6" apart, 1" deep.
Beets from Seed
Northern Illinois: April 24 to July 30 | Central Illinois: April 10 to July 15 (Fall crop) | Southern Illinois: March 27 to July 30
Sow 1" apart, ½" deep. Soak in water 24 hours before planting; thin seedlings to 2" apart.
Broccoli from Transplant
Northern Illinois: April 24 to May 15, July 15 to 30 | Central Illinois: April 10 to May 1, July 1 to 15 | Southern Illinois: March 27 to April 15, July 15 to 30
Sow ¼ - ½" deep, 12-24" apart.
Cabbage from Transplant
Northern Illinois: April 24 to July 30 | Central Illinois: April 10 to July 15 (Fall crop) | Southern Illinois: March 18 to July 30
Sow 12-24" apart.
Carrots from Seed
Northern Illinois: April 24 to July 30 | Central Illinois: April 10 to July 15 (Fall crop) | Southern Illinois: March 18 to July 30
Sow ½" apart, ½" deep. Mix with sand or soil to spread seed more evenly; keep moist during germination; thin to 1".
Cauliflower from Transplant
Northern Illinois: July 24 to Aug. 10 | Central Illinois: April 10 to May 1, July 10 to 20 (Fall crop) | Southern Illinois: June 27 to July 6
Sow 18-24" apart.
Chard from Seed or Transplant
Northern Illinois: April 24 to May 15, July 24 to Aug. 10 | Central Illinois: April 10 to June 1, July 21 to August 1 | Southern Illinois: March 27 to May 15, July 7 to 21
Sow seed 2-4" apart, 1" deep. Thin to 6" if seeded.
Corn from Seed
Northern Illinois: May 15 to July 1 | Central Illinois: May 1 to July 1 | Southern Illinois: April 15 to June 25
Sow 12" apart, 1" deep.
Cucumber from Seed
Northern Illinois: May 24 to June 30 | Central Illinois: May 10 to June 15 | Southern Illinois: April 27 to June 1
Sow 12" apart, 1" deep.
Eggplant from Transplant
Northern Illinois: May 24 to June 30 | Central Illinois: May 10 to June 15 | Southern Illinois: April 27 to June 1
Sow 18-24" apart.
Endive from Seed
Northern Illinois: April 14 to May 14, August 5 to 30 | Central Illinois: April 1 to May 1, July 21 to Aug. 15 | Southern Illinois: March 15 to April 15, July 7 to Aug. 1
Broadcast seed. Top dress with ¼" of soil, thin to 9".
Garlic Clove
Best planted in the fall
Northern Illinois: Mid-September | Central Illinois: October | Southern Illinois: Late October
Sow 2-4" apart, 1-2" deep.
Kale from Transplant
Northern Illinois: April 14 to May 14, Aug. 1 to 14 | Central Illinois: April 1 to 30, July 21 to Aug. 1 | Southern Illinois: March 15 to April 15, July 7 to 18
Seed 6" apart, ½" deep. Thin to 12".
Kohlrabi from Seed
Northern Illinois: April 8 to 20, July 15 | Central Illinois: March 25 to April 5, July 1 | Southern Illinois: March 10 to 20, June 15
Sow 4" apart, ½" deep.
Lettuce from Seed
Northern Illinois: April 15 to May 15, July 15 to Sept. 15 | Central Illinois: April 1 to 30, July 1 to Aug. 31 | Southern Illinois: March 15 to April 15, June 15 to Aug. 15
Broadcast seed. Top dress with ¼" of soil; thin to 4"; consider shade for late plantings.
Muskmelon from Seed
Northern Illinois: June 3 to 24 | Central Illinois: May 10 - June 10 | Southern Illinois: May 6 to 28
Sow 24" apart, 1" deep.
Mustard Seed
Northern Illinois: April 15 to June 15, July 15 to Sept. 15 | Central Illinois: April 1 to 30, July 1 to Aug. 31 | Southern Illinois: March 15 to April 15, June 15 to Aug. 15
Sow 4" apart, ½" deep.
Okra from Transplant
Northern Illinois: May 24 to June 30 | Central Illinois: May 10 to June 15 | Southern Illinois: April 26 to June 1
Sow 12-24" apart.
Onion (green) Sets
Northern Illinois: April 9 to May 15 | Central Illinois: March 25 to May 1 | Southern Illinois: March 11 to April 15
Sow 2" apart, 1" deep.
Parsnip from Seed
Northern Illinois: May 15 to Aug. 5 (Fall crop) | Central Illinois: May 1 to July 21 (Fall crop) | Southern Illinois: April 15 to July 7 (Fall crop)
Sow 3" apart, ½" deep. Thin to 18-24".
Peas from Seed
Northern Illinois: April 24 to May 15 | Central Illinois: March 12 to May 1 | Southern Illinois: March 27 to April 15
Sow 1" apart, 1" deep.
Pepper from Transplant
Northern Illinois: June 15 to July 30 | Central Illinois: May 10 to July 15 | Southern Illinois: May 15 to June 30
Sow 24" apart.
Potato
Northern Illinois: April 15 to 30 | Central Illinois: April 1 to 15 | Southern Illinois: March 15 to 30
Sow 12" apart, 2" deep.
Pumpkin
Northern Illinois: June 3 to 24 | Central Illinois: May 10 to June 10 | Southern Illinois: May 5 to 25
Sow 5 seeds per hill, 1" deep, 3-6' between hills. Thin to 2 or 3 best seedlings.
Radish from Seed
Northern Illinois: April 20 to June 15, Aug. 15 to Sept. 15 | Central Illinois: April 5 to June 1, Aug. 1 to 30 | Southern Illinois: March 20 to May 15, July 15 to Aug. 15
Sow 1-4" apart, ½" deep.
Rhubarb from Roots or Crown Bulbs
Northern Illinois: April 9 to May 30, Aug. 3 to 15 | Central Illinois: March 25 to May 15, July 21 to Aug. 1 | Southern Illinois: March 11 to May 1, July 7 to 14
Sow 2' apart, 2" deep. Rhubarb is a perennial crop.
Rutabaga from Seed
Northern Illinois: May 15 to Aug. 5 (Fall crop) | Central Illinois: May 1 to July 21 (Fall crop) | Southern Illinois: April 15 to July 7 (Fall crop)
Sow 2" apart, 1/2" deep. Thin to 6" when plants are 2" tall.
Spinach from Seed
Northern Illinois: April 5 to 30, Aug. 5 to Sept. 15 | Central Illinois: March 25 to April 15, July 21 to Aug. 30 | Southern Illinois: March 11 to April 1, July 7 to Aug. 15
Broadcast seed. Top dress with ½" soil; thin to 2-4.
Squash (summer) from Seed
Northern Illinois: May 24 to June 30 | Central Illinois: May 10 to June 15 | Southern Illinois: April 28 to June 1
Sow 2 seeds 24-36" apart, 1" deep. Thin weaker seedlings.
Squash (winter) from Seed
Northern Illinois: June 5 to 15 | Central Illinois: May 20 to June 1 | Southern Illinois: May 6 to May 15
Sow 4 seeds per hill, 6' between hills, 1" deep. Thin to two strongest seedlings.
Sweet Potato Slips
Northern Illinois: May 24 to June 15 | Central Illinois: May 10 to June 1 | Southern Illinois: April 28 to May 15
Sow 12" apart on a raised ridge 8" tall.
Tomato from Transplant
Northern Illinois: May 24 to June 15 | Central Illinois: May 10 to June 1 | Southern Illinois: April 28 to May 15
Sow 24-36" apart. Bury the transplant up to the bottom two leaves.
Turnip from Seed
Northern Illinois: May 15 to Aug. 5 (fall crop) | Central Illinois: May 1 to July 21, July 21 to Aug. 30 (Fall crop) | Southern Illinois: April 15 to July 7 (fall crop)
Sow 2" apart, ½" deep. Thin to 4" when plants are 4" tall.
Watermelon from Seed
Northern Illinois: May 24 to July 1 | Central Illinois: May 10 to June 15 | Southern Illinois: April 28 to June 1
Sow 3-4 seeds per hole, 4-6' apart, 1" deep. Thin to two strongest seedlings.
Originally published by former Extension horticulture educator Kelly Allsup, February 2021. Updated August 2025.