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. 

• 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!