Seedlings growing in paper eggshell cartons

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 I can in 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 & 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. 

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! 

Vegetable Type Northern Central Southern Sowing Instructions
Asparagus Crowns April 1 - 30 March 15 - April 15 March 1 - April 1 12-18" apart,
6" deep

Spread roots and cover crown bud with 2" of soil; do not harvest first year; mow foliage after fall frost

Bean (bush) Seed May 24-June 30, July 30-Aug. 14 May 10 - June 15, July 15 - 30 April 26-June 1, July 1-July 15 2-4" apart, 1" deep   
Bean (pole) Seed May 24-June 30 May 10 - June 15  April 26 - June 1 4-6" apart, 1" deep   
Beets Seed April 24-July 30 April 10 - July 15 (Fall crop) March 27 - July 30 1" apart, ½" deep Soak in water 24 hours before planting; thin seedlings to 2" apart
Broccoli Transplant April 24-May 15, July 15-30 April 10-May 1, 
July 1-15
March 27 - April 15, July 15-30 ¼ - ½" deep, 
12-24" apart
 
Cabbage Transplant April 24-July 30 April 10 - July 15 (Fall crop)  March 27 - July 30 12-24" apart  
Carrots Seed April 24-July 30 April 10 - July 15 (Fall crop)  March 27 - July 30 ½" apart, ½" deep Mix with sand or soil to spread seed more evenly; keep moist during germination; thin to 1"
Cauliflower Transplant  July 24 - Aug. 10 July 10 - 20 (Fall crop)  June 27 - July 6 18-24" apart   
Chard Seed or
Transplant 
April 24-June 14, Aug. 1-14 April 10 - June 1, July 21 - August 1 March 27-May 15, July 7-21 Seed 2-4" apart, 1" deep Thin to 6" if seeded
Corn Seed May 15-July 1 May 1 - July 9 April 15-June 25  12" apart, 1" deep  
Cucumber Seed May 24-June 30 May 10 - June 15  April 27-June1 12" apart, 1" deep  
Eggplant Transplant May 24-June 30 May 10 - June 15  April 27-June1 18-24" apart   
Endive Seed April 14-May14, August 5-30 April 1 - May 1, July 21 - August 15 March 15-April 15, July 7-Aug. 1 Broadcast seed Top dress with ¼" of soil, thin to 9"
Garlic Clove mid-September October late October 2-4" apart, 1-2" deep  
Kale Transplant April 14-May 14, August 1-14 April 1 - 30, July 21 - August 1 March 15-April 15, July 7-18 Seed 6" apart, ½" deep Thin to 12"
Kohlrabi Seed April 8-20, July 15 March 25 - April 5, July 1 March 10-20, June 15 4" apart, ½" deep  
Lettuce Seed April 15-May 15, July 15-Sept. 15 April 1 - 30, 
July 1 - August 31
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 Seed June 3-24 May 20 - June 10  May 6-28   24" apart, 1" deep 
Mustard Seed April 15-June 15, July 15-Sept. 15 April 1 - 30, July 1 - August 31 March 15-April 15, June 15-Aug. 15 4" apart, ½" deep  
Okra Transplant May 24-June 30 May 10 - June 15  April 26-June 1 12-24" apart   
Onion (green) Sets April 9-May 15 March 25 - May 1 March 11-April 15 2" apart, 1" deep   
Onion (bulb) Sets April 9-May15 March 25 - May 1 March 11-April 15 4" apart,  1" deep   
Parsnip Seed May 15-Aug. 5 (Fall crop) May 1 - July 21 (Fall crop) April 15-July 7 (Fall crop) 3" apart, ½" deep Thin to 18-24" 
Peas Seed April 24-May 15 April 10 - May 1 March 27-April 15 1" apart, 1" deep  1" apart, 1" deep 
Pepper Transplant June 15-July 30 June 1 - July 15 May 15-June 30 24" apart   
Potato Whole potato or 2 oz piece with 2 eyes April 15-30 April 1 - 15  March 15-30 12" apart, 2" deep   
Pumpkin Seed June 3-24 May 20 - June 10  May 5-25 5 seeds per hill, 1" deep, 3-6' between hills Thin to 2 or 3 best seedlings
Radish Seed April 20-June 15, Aug. 15-Sept. 15 April 5 - June 1,
 August 1 - 30
March 20-May 15, July 15-Aug. 15 1-4" apart, ½" deep   
Rhubarb Roots or
Crown buds
April 9-May 30, Aug. 3-15 March 25 - May 15, July 21 - August 1  March 11-May1, July 7-14 2' apart, 2" deep Perennial crop
Rutabaga Seed May 15-Aug. 5 (Fall crop) May 1 - July 21 (Fall crop) April 15-July 7 (Fall crop) 2" apart, 1/2" deep Thin to 6" when plants are 2" tall 
Spinach Seed April 5-30, Aug. 5-Sept. 15 March 25 - April 15, July 21 - August 30 March 11-April 1, July 7-Aug. 15 Broadcast seed Top dress with ½" soil; thin to 2-4"
Squash (summer) Seed May 24-June 30 May 10 - June 15  April 28-June 1 2 seeds 24-36" apart, 1" deep Thin weaker seedlings 
Squash (winter) Seed June 5-15 May 20 - June 1  May 6-May 15 4 seeds per hill, 6' between hills, 1" deep Thin to two strongest seedlings
Sweet Potato Slips May 24-June 15 May 10 - June 1  April 28-May 15 12" apart on a raised ridge 8" tall  
Tomato Transplant May 24-June 15 May 10 - June 1  April 28-May 15 24-36" apart Bury transplant up to bottom two leaves
Turnip Seed May 15-August 5 (fall crop) May 1 - July 21 (Fall crop) April 15-July 7 (Fall crop) 2" apart, ½" deep Thin to 4" when plants are 4" tall
Watermelon Seed May 24-July 1 May 10 - June 15  April 28-June 1 3-4 seeds per hole, 4-6' apart, 1" deep Thin to two strongest seedlings