Warm temperatures of August offer the perfect opportunity for Illinois gardeners to enjoy the rewards of their summer work—whether that means soaking in the vibrant blooms in the yard or harvesting fresh herbs and vegetables from the garden. While many growers are busy gathering their summer crops, others are getting ready for one of the most productive planting times of the year: the fall season. Knowing the right vegetables and herbs to plant in Illinois during this time can set your fall garden up for success.
Cool-season vegetables like leafy greens and root crops thrive in fall’s milder conditions. These crops typically require less frequent watering and face fewer problems from pests and weeds. As the temperatures drop, the cooler weather helps enhance flavor, often making vegetables taste sweeter and more tender.
Leafy green vegetables like kale, spinach, lettuce, arugula, and bok choy are easy to grow in cooler temperatures and can be easily sown directly into the ground or containers. Root vegetables like radishes, carrots, turnips, and beets have quick growing cycles and can continue to be planted through the early fall months.
Vegetables to Plant in Illinois in August
The following are the vegetables you can grow in Illinois during August for a healthy and productive fall garden:
Kale
Kale is a go-to green that thrives in cool weather. You can plant it in Illinois in August for a fall harvest. To get the best results, sow seeds about six weeks before the first expected frost—typically around late August to mid-September in many parts of the state. Pick a sunny spot with fertile, well-draining soil, and boost it with compost or aged manure for a richer yield.
Spinach
When planted in late August, spinach grows rapidly and provides a fresh harvest of tender leaves by October. As winter sets in, the plants may go dormant, but often perk back up in early spring with a new flush of growth. In Illinois, spinach does best when directly sown into well-prepared, nutrient-rich soil. Keep the soil consistently moist during warmer days to prevent early bolting. As temperatures begin to drop, cover the plants with a low tunnel or cloche to help extend the growing season.
Arugula
To grow arugula in Illinois this August, sow seeds in a spot that gets 4 to 6 hours of sunlight each day. Enrich the soil with worm castings or compost to enhance its nutrient content. Keep the soil evenly moist—arugula thrives in cooler temperatures and can handle a light frost. As the leaves mature, harvest them using the “cut and come again” method by picking from the outer edges to encourage continued growth.
Turnips
Both the roots and leafy tops of turnips are edible. These cool-weather root vegetables take about 60 days to mature, so planting in August allows for a solid fall harvest in Illinois. Turnips are a classic in soups, but you can also mash them with butter or toss them raw into salads. For the best flavor and texture, harvest them while they’re still young and tender—older turnips tend to get tough. For a healthy crop, plant turnips in loose, well-drained soil with full sun and keep them consistently watered.
Herbs to Plant in Illinois in August
The following are the herbs you can grow in Illinois during August for a flavorful fall herb garden:
Sage
You can grow sage in Illinois during August, as long as you provide the right growing conditions. This hardy herb loves full sun and needs well-draining soil, so choose a location that gets at least 6 to 8 hours of sunlight each day and doesn’t hold excess moisture. August is a great time to plant established sage starts or cuttings, giving them enough time to root and strengthen before the colder months arrive.
Mint
Mint is among the most invigorating and aromatic herbs you can grow, and it’s especially well-suited for Illinois gardeners in August. It’s hardy, easy to care for, and ideal for beginners. Spearmint is a popular choice for home gardens thanks to its fruity aroma and cool, crisp flavor—perfect for teas, salads, and desserts. Mint grows best in partial shade with regular watering to keep the soil moist. Since younger leaves have the strongest flavor, pick them early. Just remember that mint spreads fast, so plant it in its own container to prevent it from overtaking your garden beds.
FAQs
Is it too late to start a garden in August in Illinois?
No, August is a great time to start a fall garden with fast-growing, cool-weather crops.
Do I need to cover my fall crops in Illinois?
Yes, using row covers or cloches can protect tender plants from early frosts.
How do I keep my August crops from bolting in Illinois heat?
Water regularly and provide partial shade to help cool-season crops thrive and prevent early bolting.
