Knowing when to plant in Chicago is the single most important factor for your garden’s success. Our unique climate, with its late frosts and humid summers, demands a smart schedule. Get your timing right, and you’ll enjoy a lush, productive garden all season long. Get it wrong, and you might face stunted plants or lost crops. This guide will walk you through the optimal calendar for Chicago’s Zone 6a and 5b gardens.
When To Plant In Chicago
This core schedule is based on Chicago’s average last spring frost date of May 15th and first fall frost date of October 15th. These dates can shift by two weeks, so always watch the local forecast. Your specific microclimate also matters—gardens near the lake often get a later spring but a milder fall.
Understanding Your Chicago Garden Zone
Most of Chicago falls into USDA Hardiness Zone 6a. Some northern and western suburbs are in Zone 5b. This zone tells you which perennial plants can survive our winter. For annual vegetables and flowers, we focus more on frost dates than zone. Check your exact address on the USDA website to be sure.
Early Spring Planting (Late March – April)
This is for cold-hardy crops that can handle light frosts and cool soil. You can sow seeds directly as soon as the ground is workable (not frozen or soggy).
- Vegetables: Peas, spinach, kale, lettuce, arugula, radishes, carrots, and beets.
- Tips: Use row covers for extra protection on cold nights. Start these from seed directly in the garden; they germinate best in cool weather.
Mid-Spring Planting (May)
After the danger of frost has passed—typically from mid-May onward—it’s safe for tender crops. This is the busiest planting time.
- Vegetables: Transplant tomatoes, peppers, eggplants, and basil. Direct sow beans, cucumbers, and squash.
- Annual Flowers: Marigolds, zinnias, petunias, and other summer blooms.
Don’t rush warm-season plants. A chilly, wet soil will shock them. If you buy transplants from a greenhouse, harden them off for a week by gradually exposing them to outdoor conditions.
The “Two-Week Rule” for Warm Crops
A good Chicago strategy is to wait two weeks after the last frost date for the very tenderest crops. This means planting okra, sweet potatoes, and melons in late May or early June, when the soil is truely warm.
Summer Planting (June – July)
Summer is for succession planting. As you harvest one crop, replant the space to keep food coming.
- Plant bush beans every 2-3 weeks for a continuous harvest.
- Sow carrots and beets in early July for a sweet fall crop.
- In late July, start your fall garden seeds like broccoli, Brussels sprouts, and cabbage indoors.
Fall Planting (August – September)
Fall is a fantastic second growing season. The key is to work backward from the first fall frost.
- For harvest before frost: Plant lettuce, spinach, and radishes in August.
- For crops that sweeten after frost: Plant kale, collards, and parsnips in mid-to-late summer.
You can often protect fall crops with simple covers well into November, extending your harvest significantly.
A Month-by-Month Chicago Planting Calendar
March
Start seeds indoors for tomatoes, peppers, and broccoli. Prune dormant trees and shrubs. Prepare garden beds when soil is dry enough.
April
Direct sow peas, spinach, and radishes. Transplant hardened-off broccoli and cabbage seedlings outdoors. Divide perennials as they emerge.
May
After the 15th, plant tomatoes, peppers, and basil. Direct sow corn, beans, and squash. Plant summer-flowering bulbs like dahlias.
June
Plant successive rounds of beans and lettuce. Ensure all mulching is done to conserve moisture. Keep an eye out for early pests.
July
Start your fall broccoli and kale seeds indoors. Harvest garlic and shallots. Water deeply during dry spells, aiming for the roots not the leaves.
August
Direct sow fall lettuce, spinach, and radishes. Plant garlic cloves for next summer’s harvest. Order spring-flowering bulbs.
September
Transplant fall seedlings into the garden. Divide and replant perennials. Its a great time to add new trees and shrubs.
Step-by-Step: How to Plant Tomatoes for Chicago Success
- Wait for the Right Time: Plant outdoors on or after May 15th. Soil temperature should be above 60°F.
- Choose a Sunny Spot: Tomatoes need at least 8 hours of direct sun.
- Plant Deep: Bury the stem up to the first set of leaves. This encourages strong root growth.
- Support Immediately: Place a cage or stake at planting time to avoid damaging roots later.
- Water Well: Soak the soil thoroughly after planting and apply a layer of mulch.
Common Mistakes to Avoid
- Planting Too Early: Impatience is a gardener’s biggest enemy in Chicago. Tender plants won’t grow faster in cold soil; they’ll just suffer.
- Ignoring Soil Temperature: A warm air day doesn’t mean the soil is warm. Use a soil thermometer for accuracy.
- Skipping Hardening Off: Moving indoor seedlings directly into full sun will scorch them. Acclimate them over 7-10 days.
- Forgetting the Fall Season: Many gardeners miss out on the productive, cooler autumn growing window.
FAQ: Planting in Chicago
When is it safe to plant flowers in Chicago?
Hardy annuals like pansies can go in April. Wait until after May 15th for frost-tender flowers like impatiens and geraniums.
What is the best time to plant trees and shrubs here?
Fall (September to October) is ideal. The warm soil encourages root growth without the heat stress of summer. Spring is also good, but requires more attentive watering.
Can I start a garden in Chicago in June?
Absolutely! You can plant fast-growing crops like beans, cucumbers, and summer squash well into June for a late-summer harvest.
How do I protect plants from an unexpected late frost?
Have old sheets, frost cloth, or even cardboard boxes ready to cover vulnerable plants overnight. Remove covers in the morning.
When should I plant bulbs for spring flowers?
Plant tulips, daffodils, and crocus in October, after the soil has cooled but before it freezes. This timing helps prevent early sprouting.
By following this Chicago-specific guide, you align your gardening efforts with the natural rhythms of our climate. Paying attention to frost dates and soil temperature will make a huge difference in your harvest. Remember, gardening is part planning and part observation—keep a journal each year to refine your personal planting schedule. With this knowledge, you’re set for your most succesful growing season yet.