Originally published by Kelly Allsup, February 2, 2021.
Believe it or not, it's never too early to start making plans for this year's garden. Knowing when to plant for your area and getting your plants started right will help you maximize the growing season.
When to grow?
Planting dates are determined two things: the first and last frost dates where you grow, and how much time it takes for a crop to mature. Always check the plant tag or seed packet for the recommended date.
- Cool-Season Vegetables: These crops grow and develop best in the temperatures of early spring or fall. Some of these cool-season crops can withstand a frost without being damaged, and some are even improved by experiencing a light frost. Examples: carrots, kale, turnips, and radishes.
- Warm-Season Vegetables: These crops do not grow well in lower temperatures and must be planted well after the average last frost date. Examples: tomatoes, squash, and peppers.
What planting zone do you live in?
The U.S. Department of Agriculture provides a national Hardiness Zone map with 13 zones to help gardeners and growers pick the best plants for where they live. From top to tip, Illinois is almost 400 miles long and has five hardiness zones: 5a, 5b, 6a, 6b, and 7a.
- Northern Illinois is covered by Zone 5a in the furthest northwestern counties, while the rest is zone 5b.
- Frost-free date: May 1-10. First frost: September 21-30.
- Central Illinois spans zones 5b and 6a.
- Frost-free date: April 11-30. First frost: October 11-20.
- Southern Illinois includes zone 6a, 6b and 7a.
- Frost-free date April 1-10. First frost: October 21-30.
The frost dates are averages, but the Illinois State Water Survey has a map of the latest spring frost dates that is also a good guide to be aware of. For example, McLean County has gotten frost as late as May 28.
Southern Illinois’ longer growing season means gardeners there can start their crops about 2 weeks earlier than Central Illinois. They also can typically harvest for about two weeks longer. On the other hand, Northern Illinois has a shorter growing season and should plant 2 weeks later than I do.
Illinois Fruit and Vegetable Planting Dates
The below 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.
Need a hand?
Check out these blogs for tips on seed starting and how to grow specific vegetables.
- Starting Seeds: Starting Seeds in Spring, Easy DIY Seeding with Limited Materials, Hardening Off Indoor Seedlings
- Varieties: Cool-Season Vegetables, Warm Season Vegetables, Asparagus, Carrots, Sweet Potatoes, Lettuce, Tomatoes, Different Types of Tomatoes, Cucurbits, Different Types of Cucurbits, Peppers, Sweet Corn.
Contact us! And don't forget, if you have questions you can always reach out to horticulture staff or Master Gardeners at your nearest Illinois Extension office for a free consultation from the experts. We're here to help!
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 - June 30 or July 30 - Aug. 14 | Central Illinois: May 10 - June 15 or July 15 - 30 | Southern Illinois: April 26-June 1 or July 1-July 15
Sow 2-4 inches apart and 1 inch deep.
Pole Beans from Seed
Northern Illinois: May 24-June 30 | Central Illinois: May 10 - June 15 | Southern Illinois: April 26 - June 1
Sow 4-6" apart, 1" deep.
Beets from Seed
Northern Illinois: April 24-July 30 | Central Illinois: April 10 - July 15 (Fall crop) | Southern Illinois: March 27 - 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-May 15, July 15-30 | Central Illinois: April 10-May 1, July 1-15 | Southern Illinois: March 27 - April 15, July 15-30
Sow ¼ - ½" deep, 12-24" apart.
Cabbage from Transplant
Northern Illinois: April 24-July 30 | Central Illinois: April 10 - July 15 (Fall crop) | Southern Illinois: March 27 - July 30
Sow 12-24" apart.
Carrots from Seed
Northern Illinois: April 24-July 30 | Central Illinois: April 10 - July 15 (Fall crop) | Southern Illinois: March 27 - 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 - Aug. 10 | Central Illinois: July 10 - 20 (Fall crop) | Southern Illinois: June 27 - July 6
Sow 18-24" apart.
Chard from Seed or Transplant
Northern Illinois: April 24-June 14, Aug. 1-14 | Central Illinois: April 10 - June 1, July 21 - August 1 | Southern Illinois: March 27-May 15, July 7-21
Sow seed 2-4" apart, 1" deep. Thin to 6" if seeded.
Corn from Seed
Northern Illinois: May 15-July 1 | Central Illinois: May 1 - July 9 | Southern Illinois: April 15-June 25
Sow 12" apart, 1" deep.
Cucumber from Seed
Northern Illinois: May 24-June 30 | Central Illinois: May 10 - June 15 | Southern Illinois: April 27-June1
Sow 12" apart, 1" deep.
Eggplant from Transplant
Northern Illinois: May 24-June 30 | Central Illinois: May 10 - June 15 | Southern Illinois: April 27-June1
Sow 18-24" apart.
Endive from Seed
Northern Illinois: April 14-May14, August 5-30 | Central Illinois: April 1 - May 1, July 21 - August 15 | Southern Illinois: March 15-April 15, July 7-Aug. 1
Broadcast seed. Top dress with ¼" of soil, thin to 9".
Garlic Clove
Best planted in 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-May 14, August 1-14 | Central Illinois: April 1 - 30, July 21 - August 1 | Southern Illinois: March 15-April 15, July 7-18
Seed 6" apart, ½" deep. Thin to 12".
Kohlrabi from Seed
Northern Illinois: April 8-20, July 15 | Central Illinois: March 25 - April 5, July 1 | Southern Illinois: March 10-20, June 15
Sow 4" apart, ½" deep.
Lettuce from Seed
Northern Illinois: April 15-May 15, July 15-Sept. 15 | Central Illinois: April 1 - 30, July 1 - August 31 | Southern Illinois: March 15-April 15, June 15-Aug. 15
Broadcast seed. Top dress with ¼" of soil; thin to 4"; consider shade for late plantings.
Muskmelon from Seed
Northern Illinois: June 3-24 | Central Illinois: May 20 - June 10 | Southern Illinois: May 6-28
Sow 24" apart, 1" deep.
Mustard Seed
Northern Illinois: April 15-June 15, July 15-Sept. 15 | Central Illinois: April 1 - 30, July 1 - August 31 | Southern Illinois: March 15-April 15, June 15-Aug. 15
Sow 4" apart, ½" deep.
Okra from Transplant
Northern Illinois: May 24-June 30 | Central Illinois: May 10 - June 15 | Southern Illinois: April 26-June 1
Sow 12-24" apart.
Onion (green) Sets
Northern Illinois: April 9-May 15 | Central Illinois: March 25 - May 1 | Southern Illinois: March 11-April 15
Sow 2" apart, 1" deep.
Parsnip from Seed
Northern Illinois: May 15-Aug. 5 (Fall crop) | Central Illinois: May 1 - July 21 (Fall crop) | Southern Illinois: April 15-July 7 (Fall crop)
Sow 3" apart, ½" deep. Thin to 18-24".
Peas from Seed
Northern Illinois: April 24-May 15 | Central Illinois: April 10 - May 1 | Southern Illinois: March 27-April 15
Sow 1" apart, 1" deep.
Pepper from Transplant
Northern Illinois: June 15-July 30 | Central Illinois: June 1 - July 15 | Southern Illinois: May 15-June 30
Sow 24" apart.
Potato
Northern Illinois: April 15-30 | Central Illinois: April 1 - 15 | Southern Illinois: March 15-30
Sow 12" apart, 2" deep.
Pumpkin
Northern Illinois: June 3-24 | Central Illinois: May 20 - June 10 | Southern Illinois: May 5-25
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-June 15, Aug. 15-Sept. 15 | Central Illinois: April 5 - June 1, August 1 - 30 | Southern Illinois: March 20-May 15, July 15-Aug. 15
Sow 1-4" apart, ½" deep.
Rhubarb from Roots or Crown Bulbs
Northern Illinois: April 9-May 30, Aug. 3-15 | Central Illinois: March 25 - May 15, July 21 - August 1 | Southern Illinois: March 11-May1, July 7-14
Sow 2' apart, 2" deep. Rhubarb is a perennial crop.
Rutabaga from Seed
Northern Illinois: May 15-Aug. 5 (Fall crop) | Central Illinois: May 1 - July 21 (Fall crop) | Southern Illinois: April 15-July 7 (Fall crop)
Sow 2" apart, 1/2" deep. Thin to 6" when plants are 2" tall.
Spinach from Seed
Northern Illinois: April 5-30, Aug. 5-Sept. 15 | Central Illinois: March 25 - April 15, July 21 - August 30 | Southern Illinois: March 11-April 1, July 7-Aug. 15
Broadcast seed. Top dress with ½" soil; thin to 2-4.
Squash (summer) from Seed
Northern Illinois: May 24-June 30 | Central Illinois: May 10 - June 15 | Southern Illinois: April 28-June 1
Sow 2 seeds 24-36" apart, 1" deep. Thin weaker seedlings.
Squash (winter) from Seed
Northern Illinois: June 5-15 | Central Illinois: May 20 - June 1 | Southern Illinois: May 6-May 15
Sow 4 seeds per hill, 6' between hills, 1" deep. Thin to two strongest seedlings.
Sweet Potato Slips
Northern Illinois: May 24-June 15 | Central Illinois: May 10 - June 1 | Southern Illinois: April 28-May 15
Sow 12" apart on a raised ridge 8" tall.
Tomato from Transplant
Northern Illinois: May 24-June 15 | Central Illinois: May 10 - June 1 | Southern Illinois: April 28-May 15
Sow 24-36" apart. Bury transplant up to bottom two leaves.
Turnip from Seed
Northern Illinois: May 15-August 5 (fall crop) | Central Illinois: May 1 - July 21 (Fall crop) | Southern Illinois: April 15-July 7 (Fall crop)
Sow 2" apart, ½" deep. Thin to 4" when plants are 4" tall.
Watermelon from Seed
Northern Illinois: ay 24-July 1 | Central Illinois: May 10 - June 15 | Southern Illinois: April 28-June 1
Sow 3-4 seeds per hole, 4-6' apart, 1" deep. Thin to two strongest seedlings.