How to Grow Sunflowers in Oklahoma
This page may contain affiliate links. Learn More.
Learning how to grow Sunflowers in Oklahoma is easier than you might think. They are a cheerful and rewarding crop to grow in our sunny and variable climate. And simple, even for beginning gardeners!
Whether you’re planting them for beauty, pollinators, or seeds, these bold blooms thrive in the state’s long, hot summers. With plenty of sunshine, well-draining soil, and a few simple care tips, sunflowers can brighten up gardens, yards, and even small spaces like containers.
Oklahoma gardeners will appreciate how easy sunflowers are to grow and how well they tolerate the state’s weather conditions once established.
Best Time to Plant Sunflowers in Oklahoma
The ideal time to plant sunflower seeds in Oklahoma is between mid-April and mid-May, once the soil has warmed to at least 50-60°F. In southern parts of the state, you may be able to plant a little earlier, while gardeners in northern Oklahoma should wait until after the last frost.
You can also stagger your plantings every two to three weeks for a longer bloom season extending into late summer and early fall. Sunflowers are very sensitive to frost, so it’s best to plant them after all danger of cold weather has passed.
We try to add sunflowers to our preschool garden every year. There are tons of great and fun lessons you can do with them. Measuring how tall they grow, counting seeds, even the process of harvesting the seeds is incredible and very interesting. You can roast them and eat them too! Or use them for bird feeders. The options are unlimited!
For more information on what to plant when, check this month by month garden guide!
Choosing the Right Sunflower Varieties
Sunflowers come in a wide range of sizes, colors, and forms. In Oklahoma, you can grow both ornamental and edible varieties. Here are some great types to consider:
- Mammoth Sunflowers – Classic tall sunflowers with huge yellow blooms and large seeds, perfect for roasting or birdseed. These are some of our favorites!
- Autumn Beauty – A multi-branching type with blooms in red, orange, and yellow shades. Adds a fall-like feel to gardens.
- Lemon Queen – A pollinator favorite with soft yellow petals and mid-sized growth. Great for bee gardens.
- Teddy Bear – A dwarf, fluffy-looking variety ideal for containers or small gardens.
- Sunspot – Another smaller variety that still produces large blooms. Good for kids or small-space gardeners.
If you’re planting to harvest seeds, choose varieties labeled as edible or seed-producing. For cut flowers or landscaping, focus on branching types that produce multiple blooms per plant.
Preparing the Soil for Sunflowers
Sunflowers prefer loose, well-drained soil that’s slightly acidic to neutral (pH 6.0–7.5). Oklahoma’s soil varies across the state, so it’s helpful to do a quick soil test. If you have clay-heavy soil, amend it with compost, aged manure, or sand to improve drainage and texture. Sunflowers don’t like soggy roots, so avoid planting them in low-lying spots where water tends to pool.
Work the soil to a depth of at least 12-18 inches before planting, especially for tall sunflower varieties that develop deep taproots. Mix in organic matter to boost nutrients and water retention, especially in sandy areas of western Oklahoma.
If you want to read the full story of how we got started growing our own food at Little Sprouts and get all the basics to start yourself, check this out. The Journey of the Little Sprouts: A Guide for Growing a Better Tomorrow.
How to Plant Sunflower Seeds
Sunflower seeds are large and easy to handle, making them perfect for planting by hand or with kids. To plant:
- Sow seeds directly into the garden once the soil is warm and all frost danger is gone.
- Plant seeds about 1 inch deep. (When we first tried to grow them, we planted them way too deep, so pay attention here)
- Space seeds 6 inches apart for smaller varieties or 12-24 inches apart for large, branching types.
- Water well after planting, and keep the soil moist until seeds germinate, usually in 7-10 days.
Once the seedlings are about 6 inches tall, thin them to the appropriate spacing to avoid overcrowding. Overcrowded sunflowers won’t grow as tall or bloom as fully.
Watering and Fertilizing Sunflowers
Sunflowers are fairly drought-tolerant once they’re established, but they grow best with consistent moisture, especially during early growth and when they’re setting flowers. In Oklahoma’s hot summers, water deeply once or twice a week, depending on rainfall. Deep watering encourages strong roots and helps the plant resist wind and dry spells.
Avoid overwatering or keeping the soil soggy, as this can lead to root rot. Mulching around the base of your plants with straw or leaves can help retain moisture and reduce weeds.
Sunflowers don’t need a lot of fertilizer, but a light application of a balanced, slow-release fertilizer at planting time can boost growth. If your soil is poor or sandy, you may apply a low-nitrogen fertilizer again when the plants are about a foot tall.
✔Here’s a link to a great vegetable garden planner you can print right out and use at home! So cute!
Supporting Tall Sunflower Varieties
Many sunflower types, especially the giant varieties, can reach 6 to 12 feet tall. These tall plants can sometimes become top-heavy, especially in Oklahoma’s windy conditions. To keep them from falling over:
- Plant them in a spot sheltered from strong wind, such as near a fence or building.
- Use stakes to support very tall varieties.
- Group sunflowers close enough together that they can support each other without overcrowding.
Proper watering and healthy roots also help the plants anchor themselves firmly in the ground.
Pests and Problems to Watch For
Sunflowers are tough plants, but they can occasionally suffer from a few pests and diseases in Oklahoma. Keep an eye out for:
- Aphids – Small, sap-sucking insects often found on young leaves. Rinse off with a strong spray of water or use insecticidal soap.
- Cutworms – These can chew through young stems at the soil level. Protect new seedlings with collars made from paper cups or toilet paper rolls.
- Sunflower beetles and caterpillars – These may nibble on leaves. Handpick or use organic insecticides if needed.
- Powdery mildew or rust – Moist, humid conditions can lead to fungal problems. Space plants well and avoid watering from overhead.
Most of the time, sunflowers grow happily with minimal care and few issues, especially if they’re planted in full sun and well-draining soil.
Harvesting Sunflowers for Seeds or Decor
Sunflowers can be harvested for different purposes, depending on the variety and your goals. For seeds, let the flower heads mature on the plant. The back of the head will turn yellow and then brown, and seeds will begin to loosen. Cover the head with a paper bag or mesh cloth to keep birds away, and cut it once it’s fully dry.
To use sunflowers for indoor decor, cut the stems when the flowers are just starting to open and place them in water. Choose branching varieties if you want lots of blooms for vases.
For dried sunflower heads, let them dry on the stalk or bring them indoors once the back of the head turns brown. Store in a dry place to prevent mold.
Saving Seeds for Next Season
To save seeds for replanting, choose a non-hybrid (heirloom) variety. Let the flower dry completely, remove the seeds by rubbing them from the head, and store them in a paper envelope in a cool, dry place. Label the variety and date so you can use them next year. In Oklahoma, saved sunflower seeds can be started again the following spring with great success.
Attracting Pollinators and Wildlife
Sunflowers are excellent for attracting pollinators like bees, butterflies, and even hummingbirds. Their nectar-rich centers are a magnet for beneficial insects, and they also provide food for birds like finches once the seeds are ready. Consider planting sunflowers near your vegetable garden to boost pollination or around the edge of your yard to bring in helpful wildlife.
If you leave some flower heads standing through the fall, they’ll continue to feed birds long after other food sources have faded.
Growing Sunflowers with Kids
Sunflowers are a perfect project for children in Oklahoma home gardens or daycares. Their fast growth and dramatic size make them fun and exciting to watch. Let kids plant their own seeds, measure growth weekly, and harvest seeds to roast or feed to birds. Dwarf varieties are especially fun for younger children and make great container plants. My kids LOVE to do it.
Sunflowers in the Oklahoma Landscape
Sunflowers can be more than just a garden crop—they can also be used as a border, privacy screen, or seasonal backdrop. Their bright, towering flowers make a bold statement in any landscape, especially when planted en masse. Try mixing different varieties for a rainbow of heights and colors. They pair beautifully with zinnias, cosmos, marigolds, and other Oklahoma-hardy summer flowers.
Whether you’re growing sunflowers for fun, food, or pollinators, these radiant blooms are a low-maintenance and high-reward addition to any Oklahoma garden. With plenty of sunshine and a little planning, you’ll be rewarded with sunny faces that turn toward the light—and bring joy to everyone who sees them.
