When To Plant Cilantro In Illinois

The best time to plant cilantro in Illinois is in early spring, right after the last frost has passed, and again in late summer for a fall harvest.
 
Cilantro is a cool-season herb that thrives in Illinois’ unpredictable weather because it bolts, or goes to seed, quickly once temperatures heat up.
 
If you’ve been wondering when to plant cilantro in Illinois, the short answer is you have two perfect windows: March through May and August through September, depending on your specific zone.
 
Getting the timing right for when to plant cilantro in Illinois makes all the difference between a lush, leafy harvest and a bitter, seedy disappointment.
 
In this post, we’ll break down the exact months to plant cilantro in Illinois, how to stagger your plantings, and tips to keep it growing longer.
 
Let’s dig in so you can enjoy fresh cilantro all season long.
 

When to Plant Cilantro in Illinois: The Two Perfect Windows

When it comes to when to plant cilantro in Illinois, you have two distinct planting seasons that align with the state’s climate.
 
The first window is for a spring crop, and the second is for a fall crop that often tastes even better because cooler weather prevents bolting.
 
Here’s a closer look at both.
 

1. Spring Planting: March to Early May

The spring window for when to plant cilantro in Illinois runs from mid-March in southern parts of the state to early May in northern regions.
 
Cilantro seeds actually germinate best in soil temperatures between 55°F and 68°F, so you don’t need to wait for warm weather.
 
You can plant cilantro in Illinois as soon as the soil is workable and not waterlogged from snowmelt or spring rains.
 
A good rule of thumb is to sow seeds about two to three weeks before your area’s average last frost date, which is typically April 15 in central Illinois.
 
If you live near Chicago or Rockford, push that to early May, while gardeners in Carbondale can start as early as mid-March.
 
The key trick for when to plant cilantro in Illinois in spring is to do it in succession, meaning you sow new seeds every two weeks.
 
This way, you’ll have a continuous supply of leaves before the heat of June triggers flowering.
 

2. Fall Planting: Late July to Mid-September

The second and often better window for when to plant cilantro in Illinois is late summer, from late July through mid-September.
 
Many Illinois gardeners are surprised to learn that fall cilantro is actually more flavorful and slower to bolt than spring crops.
 
When you plant cilantro in Illinois during this period, the seeds germinate in warm soil, but the plants mature as temperatures cool down.
 
The result is larger leaves, a milder flavor, and a longer harvest window that can last into November if you use a cold frame or row cover.
 
For northern Illinois, aim for late July to late August planting dates.
 
For central and southern Illinois, you can stretch planting into early September since your first frost arrives later.
 
Just remember that cilantro needs about 50 to 60 days to reach full size, so count backward from your first expected frost date to nail the timing.
 

Factors That Affect When to Plant Cilantro in Illinois

Knowing when to plant cilantro in Illinois isn’t just about picking a month, it’s about understanding how your local conditions influence that timing.
 
Here are the main factors that can shift your planting schedule.
 

1. Your USDA Hardiness Zone

Illinois spans zones 5a in the north to 7a in the far south, and this dramatically affects when to plant cilantro in Illinois.
 
Zone 5 gardeners in places like Peoria should plant spring cilantro in late April and fall cilantro in early August.
 
Zone 6 gardeners in Springfield can plant spring cilantro in early April and fall cilantro in late August.
 
Zone 7 gardeners in the southern tip can plant spring cilantro in mid-March and fall cilantro in mid-September.
 
Checking your zone is the fastest way to customize when to plant cilantro in Illinois for your exact backyard.
 

2. Soil Temperature and Moisture

Cilantro seeds are notoriously finicky about soil temperature, so this factor directly dictates when to plant cilantro in Illinois.
 
If soil is too cold, below 50°F, seeds will rot or germinate very slowly, and if it’s above 75°F, they’ll stall and bolt quickly.
 
Use a soil thermometer to check that your ground is in that sweet spot of 55°F to 68°F before sowing.
 
Also, don’t plant after a heavy rain, as overly wet soil can cause damping-off disease, which kills seedlings overnight.
 
Wait for the soil to dry out just enough that it crumbles in your hand, and you’ll know it’s time to plant cilantro in Illinois.
 

3. Bolting Risk and Day Length

Day length is another underrated factor in when to plant cilantro in Illinois, as cilantro is a long-day plant.
 
When days exceed 14 hours, usually from late May to early July in Illinois, cilantro naturally starts flowering and producing seeds.
 
This means that even if you stagger your spring plantings, the June solstice will force all your plants to bolt.
 
That’s why fall planting is so effective, as days are getting shorter, which encourages leaf growth instead of seed production.
 
So when you’re deciding when to plant cilantro in Illinois, avoid any dates that would put your plants maturing during the first two weeks of June.
 

Pro Tips for Success When You Plant Cilantro in Illinois

Once you’ve figured out when to plant cilantro in Illinois, a few practical tricks will help your crop thrive.
 

1. Soak Seeds Before Planting

Cilantro seeds have a hard outer shell that delays germination, so soak them in water for 24 hours before planting.
 
This simple step can cut germination time in half, which matters when you’re racing against the Illinois heat.
 

2. Plant in Partial Shade for Summer

If you want to extend your spring crop past when to plant cilantro in Illinois, sow seeds in a spot that gets morning sun and afternoon shade.
 
This microclimate will slow down bolting by keeping soil temperatures cooler.
 

3. Use Row Covers for Fall

For fall plantings, have a floating row cover ready to protect your cilantro from early frosts, which lets you harvest well into late November.
 

So, When to Plant Cilantro in Illinois?

So, when to plant cilantro in Illinois is best answered with two clear seasons: early spring and late summer.
 
You should plant cilantro in Illinois in March and April for a spring harvest, and again in August and September for a fall harvest.
 
The exact dates depend on your zone, but the pattern is the same across the entire state.
 
Avoid planting during the hot, long days of June and July, as your cilantro will bolt before you get a good harvest.
 
Hope this guide has cleared up when to plant cilantro in Illinois so you can grow fresh, flavorful leaves all year.
 
Happy planting, and enjoy that amazing taste of homegrown cilantro.