Below is a detailed guide that will help you decide what to plant in August in Illinois, taking into account temperature tolerances, planting dates, and special considerations for each plant type.

Vegetables To Plant

Illinois’ rich soil and favorable climate make it possible to grow a diverse array of vegetables well into the fall. August is a good time to sow seeds for fall crops and to transplant seedlings that can thrive in cooler weather. Below are ten vegetables you can successfully plant this month.

Broccoli

Broccoli is a versatile, nutritious vegetable that thrives in cooler temperatures. In Illinois, August is ideal for starting new seedlings to harvest in late fall. Plant transplants about 12 to 14 weeks before the average first frost date, typically around mid-October. Broccoli does well in fertile, well-drained soil, and while it can tolerate light frost, prolonged exposure may harm the heads. Look for varieties such as ‘Green Magic’ that mature quickly.

Kale

Kale is another excellent choice for August planting in Illinois. This leafy green is hardy and can withstand frost, making it perfect for planting in late summer. Direct sow seeds or transplant seedlings approximately 8 to 10 weeks before the frost. Kale thrives in cooler temperatures, allowing it to become sweeter after a touch of frost. Popular varieties include ‘Winterbor’ and ‘Lacinato,’ both renowned for their flavor and texture.

Spinach

Spinach is a fast-growing leafy green that thrives in cooler weather. August planting allows for a quick harvest before the first frost. Seeds can be sown directly into the garden about 6 weeks before the frost arrives. Spinach prefers moist, rich soil and can be harvested multiple times by cutting the outer leaves, promoting continual growth. ‘Bloomsdale’ and ‘Tyee’ are excellent varieties to consider for robust yields.

Carrots

Carrots are a delightful root vegetable that can be sown in August for an autumn harvest. Plant the seeds directly in well-tilled soil—preferably around mid-August to allow about 10 to 12 weeks of growth before the soil freezes. Carrots prefer cooler conditions for optimal sweetness. The ‘Nantes’ and ‘Imperator’ varieties are particularly good choices, as they are known for their sweetness and ease of growth in colder weather.

Beets

Beets are root vegetables that grow well in cooler weather, making August an ideal time to sow seeds. They typically require 50 to 70 days to reach maturity, allowing enough time for a harvest before the frost. Sow seeds directly in the ground about 1 inch deep. Varieties like ‘Detroit Dark Red’ and ‘Chioggia’ not only taste great but also add color to your garden. Beets are also known for their versatility, as both the roots and greens are edible.

Radishes

Radishes are among the fastest-growing crops that can be planted in August. They flourish in the cooler temperatures of late summer and can sprout in as little as three weeks. For a continuous harvest, sow seeds every two to three weeks. Varieties such as ‘Cherry Belle’ and ‘French Breakfast’ are great candidates. The crispness and peppery flavor of radishes make them a popular choice for salads and garnishes.

Lettuce

Lettuce grows best in cool weather, making August an optimal month to sow seeds for a fall crop. You can sow different varieties for staggered harvesting: direct sow seeds of loose-leaf, romaine, or butterhead lettuce several weeks apart. Varieties like ‘Buttercrunch’ and ‘Red Romaine’ create delicious summer and fall salads. Ensure consistent moisture during the germination period for the best results.

Swiss Chard

Swiss chard is a highly nutritious leafy green that grows well in diverse conditions. It’s well-suited for late summer planting, with a maturation period of around 50 to 60 days. Plant seeds directly in the ground about 1 to 2 inches apart, and ensure they receive full sun to partial shade. Varieties such as ‘Rainbow’ and ‘Fordhook Giant’ are popular for their vibrant colors and robust leaves, which can withstand the cooler fall temperatures.

Turnips

Turnips are another root vegetable that performs well in the cooler temperatures of late summer. Sow seeds directly into the garden bed about 10 to 12 weeks before the first expected frost. They like well-drained soil and can be harvested when they reach golf ball size. Varieties such as ‘Red Marble’ and ‘Hakurei’ are great choices for sweet, tender roots.

Peas

Although traditionally sown in early spring, certain pea varieties can be grown in late summer for an autumn harvest. Planting do not require a lengthy growing season, which makes mid to late August a fine time to sow seeds. Choose less common varieties like ‘Mammoth Melting Sugar’ for shelling or ‘Sugar Snap’ for snacking. Peas prefer cool weather and will thrive as the temperatures drop moving into fall.

Flowers To Plant

August is also an excellent time to plant certain flowers that can enhance your garden’s aesthetics while still providing blooms before the first frost. Flowering in the cooler months of autumn can add an additional dimension of beauty to gardens across Illinois. Here are some splendid options.

Mums (Chrysanthemums)

Mums are the quintessential fall flowers that bloom from late summer into fall, offering vibrant colors such as red, yellow, pink, and white. Dividing or planting newly purchased plants in August can yield a beautiful display as the weather cools. Mums thrive in full sun and well-drained soil. They require minimal maintenance once established, and while they can tolerate light frost, it’s best to plant them with enough time to set their roots.

Asters

Asters are perennial flowers that produce lovely star-shaped blooms in various colors. They typically flower in late summer through fall; planting them in August allows time for root establishment before the frost. Asters appreciate well-drained soil and a sunny position. Varieties such as ‘Purple Dome’ and ‘Alma Potschke’ are noted for their hardiness and cheerful flowers that attract pollinators.

Sedum

Sedum, also known as stonecrop, is a hardy succulent that thrives in dry conditions. Planting in August gives them time to establish before fall arrives. These low-maintenance perennials feature stunning clusters of star-shaped flowers that bloom in late summer, drawing butterflies and bees. Varieties like ‘Autumn Joy’ are popular for their vibrant pink blooms that deepen to a warm copper in the fall, making them a great addition to any garden.

Black-eyed Susans (Rudbeckia)

Black-eyed Susans are vibrant, golden-yellow flowers that bloom profusely until frost. Planting these cheerful perennials in August allows them to establish roots in the warm soil, enabling a robust display of blooms by the fall. They thrive in full sun and are relatively drought-tolerant. Their resilience attracts pollinators, providing a colorful highlight to your garden landscape.

Zinnias

Zinnias are annual flowers known for their bright and bold colors. August planting can extend the blooming period well into the fall, especially when sowing seeds after the last frost. With a straightforward growth process, zinnias prefer full sunlight and well-drained soil, making them ideal for colorful borders or cut flowers. Varieties like ‘State Fair’ and ‘Benary’s Giant’ stand out for their size and vibrancy.

Cosmos

Cosmos are striking annual flowers that thrive in warm weather and bloom profusely until the frost hits. Sowing seeds or transplanting in August provides ample time for them to reach full height and flower before cold temperatures set in. Cosmos prefer sunny spots and are drought-tolerant. They come in various colors, including pink, white, and crimson, and are fantastic for attracting butterflies.

Pansies

Pansies are cool-season flowers that thrive in the fall. You can plant them as seeds or transplants in August; they will flourish as temperatures begin to cool. Pansies can tolerate a light frost and often revive beautifully after cold snaps. Available in an array of colors, they add vibrancy to gardens and containers.

Snapdragons

Snapdragons are annuals that can also be grown as perennials in milder climates. By planting them in August, growers can expect flowers into the fall. They enjoy full sun with some afternoon shade and perform best in rich, well-drained soil. Varieties like ‘Rocket’ feature tall spikes that can add height to your garden and attract bees and butterflies.

Ornamental Kale

Ornamental kale adds unique color and texture to gardens as the weather cools. Planting in August allows these plants to establish themselves, providing an eye-catching display with bright colors as fall progresses. Ornamental kale thrives in full sun and can withstand colder temperatures, becoming even more vibrant after exposure to frost.

Marigolds

Marigolds are hardy annuals that bloom vigorously until frost. Planting seeds or transplants in August can extend the blooming season and add warmth to your flower beds. Marigolds thrive in full sunlight and are known for their pest-repelling properties, making them great companions in vegetable gardens. Varieties such as ‘French Marigold’ and ‘African Marigold’ offer a variety of heights and colors for your garden.

Herbs To Plant

When it comes to herbs, August in Illinois presents a fantastic opportunity to establish perennial herbs that can continue to produce through late summer and into the fall. Many herbs can thrive in the cooler temperatures of late summer, offering fresh flavors for cooking and additional benefits for your garden. Here is a selection of ten herbs you can plant in August.

Basil

Basil is a warm-season herb favored for its aromatic leaves. Though it’s typically planted in spring, you can still sow seeds or start transplants in early August for a late harvest. Basil thrives in full sun and prefers well-drained soil. Harvest leaves consistently to promote growth; varieties like ‘Genovese’ and ‘Thai Basil’ are popular choices for culinary use.

Cilantro

Cilantro is a cool-season herb that can be sown in August for a fall crop. It prefers cooler temperatures and can bolt quickly in the heat. Plant seeds directly into the soil, and they will germinate best when the temperatures moderate. Cilantro grows rapidly and can be harvested in about 3 to 4 weeks. It thrives in well-drained soil and is best known for its fresh and sharp flavor in many dishes.

Chives

Chives are perennial herbs that can be planted in August. Their delicate, green stems and purple flowers add both flavor and visual interest to gardens. Chives prefer well-drained soil and can grow in partial shade, making them easy to maintain. Once established, they provide an abundant harvest each season and can be snipped anytime for fresh culinary use.

Thyme

Thyme is a perennial herb that loves cooler temperatures and can be seeded or transplanted in August. It prefers well-drained soil and full sun, and once established, it requires very little care. Thyme can be harvested throughout the season, and varieties like English Thyme and Lemon Thyme are superb for culinary uses. Thyme is drought-resistant, making it a great low-maintenance herb for garden beds or pots.

Oregano

Oregano is a hardy perennial herb that can be planted in late summer. It thrives in well-drained soil and full sun, and once established, it is relatively drought-tolerant. Planting in August allows oregano to establish roots before the colder months arrive. Varieties like Greek Oregano and Mexican Oregano offer different flavors and thrive in the garden or containers. Harvest the leaves regularly, as this promotes new growth.

Dill

Dill is an annual herb that you can plant in August for fall harvests. Known for its feathery leaves and aromatic seeds, dill thrives in full sun and prefers well-drained soil. It grows quickly and can be harvested within weeks. Choosing to plant varieties like ‘Bouquet’ or ‘Fernleaf’ can enhance your cooking with a fresh anise-like flavor. Dill attracts beneficial insects, making it an excellent addition to a vegetable garden.

Parsley

Parsley is a biennial herb often grown as an annual, making August a fitting time to sow seeds for fall harvest. It requires full sun but thrives in partial shade as well. Plants started in August can produce leaves before frost, and they are perfect for garnishing dishes. Flat-leaf and curly varieties are both popular; their versatility in the kitchen is unmatched.

Sage

Sage is a hardy perennial herb that can be planted in August. It prefers dry, well-drained soil in full sun. With its strong aroma and robust flavor, sage is often used in savory dishes. Established plants offer continuous harvests of leaves throughout the year. Varieties like ‘Berggarten’ are known for their wide, thick leaves, ideal for culinary uses.

Mint

Mint is a vigorous perennial herb that can be planted in August. Though it spreads quickly, growing it in containers or confined spaces can help manage its growth. Mint thrives in moist, rich soil in partial to full sun, and its refreshing leaves can be used in a variety of dishes and beverages. Varieties like Peppermint and Spearmint offer different flavors and scents, adding diversity to your herb garden.

Fennel

Fennel is a unique herb that can be sown in August for fall use. It prefers full sun and grows best in well-drained soil with adequate moisture. Fennel produces a bulbous base, tall fronds, and seeds that all can be utilized in cooking. It has a distinct anise flavor that complements a variety of dishes. Choose varieties like ‘Florence’ for a sweet and tender bulb.

Landscape Plants To Plant

Enhancing your landscape during the month of August can prepare your outdoor space for a stunning fall display. Many landscape plants prefer the warmer soils of late summer for transplanting, allowing them to establish roots before the onset of colder weather. Below is a list of ten landscape plants well-suited for planting in this time frame.

Ornamental Grasses

Ornamental grasses like Miscanthus and Panicum are perfect for adding texture and movement to your garden. August planting allows them enough time to develop strong roots before winter. They thrive in well-drained soil and full sun, and their stunning plumes will add interest to your landscape well into the colder months. Varieties like ‘Morning Light’ and ‘Shenandoah’ are popular for their striking appearance.

Hostas

Hostas are shade-loving perennials that excel in cooler climates. August is a wonderful time to plant divisions or new hostas, allowing them to settle in before the first frost. They prefer well-drained soil and consistent moisture. Hostas come in a variety of sizes and colors, with options like ‘Blue Angel’ or ‘Sum and Substance’ known for their impressive foliage.

Hydrangeas

Hydrangeas are beloved for their lush blooms, and August is an ideal time to plant these perennials. Varieties such as ‘Endless Summer’ or ‘Annabelle’ can tolerate the warm soil while establishing their roots for vibrant blooms in the coming years. They thrive in well-drained soil with plenty of moisture. It’s essential to choose the right type of hydrangea based on your soil pH for optimal blooming.

Daylilies (Hemerocallis)

Daylilies are resilient perennials that can tolerate drought and thrive in various soil types. August is an excellent time to plant them, as they establish well before the frost. They prefer full sun to partial shade and will produce eye-catching flowers in a spectrum of colors. Picking varieties like ‘Stella de Oro’ offers repeat blooms and is a favorite among gardeners.

Coneflowers (Echinacea)

Coneflowers are hardy perennials that bloom from summer into fall, attracting bees and butterflies to your garden. Planting in August allows these resilient plants to develop strong roots. They thrive in full sun and can tolerate a variety of soil conditions. Varieties like ‘Pink Pony’ and ‘Magnus’ can be excellent choices for vibrant displays and medicinal uses.

Spirea

Spirea is a deciduous shrub that performs well in a variety of soil types while thriving in full sun. August planting enables the shrub to establish roots before cooler weather arrives, leading to beautiful blooms in the spring. Varieties like ‘Candlelight’ or ‘Anthony Waterer’ offer vibrant foliage and flowers that enhance landscape charm.

Japanese Maple

Japanese maples are stunning landscape trees known for their delicately shaped leaves and vibrant fall colors. While they can be planted year-round, August is an excellent time to establish young trees before winter dormancy. They prefer well-drained soil and partial shade, making them ideal for adding interest as stand-alone focal points or garden accents.

Barberry (Berberis)

Barberry shrubs are drought-tolerant plants that add color and interest to landscapes. They can be planted in August to encourage root growth before winter. Barberry thrives in full sun to partial shade and prefers well-draining soil. Varieties like ‘Crimson Carousel’ are popular for their vibrant foliage and adaptability to various landscapes.

Liriope

Liriope is a versatile perennial that can be planted in August for consistent growth. Often used as a ground cover or border plant, it thrives in a variety of soil conditions and partial to full shade. Liriope’s grass-like leaves and spikes of purple flowers add texture to gardens and landscapes, and it requires minimal maintenance once established.

Weigela

Weigela is a deciduous shrub valued for its attractive trumpeting flowers and bushy growth. August planting allows for establishment before frost, leading to robust blooms in the spring. These plants thrive in full sun and can adapt to various conditions. Varieties like ‘Wine & Roses’ are known for their striking leaves and abundant flowers, ideal for creating eye-catching landscapes.