Nothing says summer like bright rows of brilliant Helianthus flowers, commonly known of as sunflowers. Easy to grow, this North American native is a fun plant to add to your vegetable or flower garden. Most people think of sunflowers as the towering varieties filling fields in the prairie states. However, many garden cultivars are designed to be compact and grown in a wide range of hardiness zones. You can choose sunflowers in many different colors featuring heights between 4 to 12 feet.
Often seen as a border plant to give height to the back of a flower bed, sunflowers are multipurpose. They provide beauty to your garden and are a food source for birds and squirrels. Cutting them brings their sunny faces inside for floral arrangements. Many sunflowers feature big, beautiful blooms and can be harvested for their tasty seeds or a rich sunflower oil. If you’re wondering how to plant sunflowers and how to take care of sunflowers in your garden, look no further. All you need is a few simple tips to get the most out of your garden sunflowers.
How to Plant Sunflower Seeds
Planting sunflower seeds is a quick and easy task. By taking the time to choose the right location and prepare the soil, you give these plants the strongest possible start.
1. Choose a Sunny Spot
It almost goes without saying that sunflowers love the sun. Look for a spot with plenty of sun for these fast-growing annuals. Think about what you’ll plant around or near your sunflowers. Most sunflowers grow quite tall and may cast shade on other plants. The short growing season of between 70 to 100 days allows for planting throughout most gardening zones.
2. Prepare the Soil
Well-draining soil is essential. If your soil is heavy, mix in up to 4 inches of compost. Add nutrients to soil with a complete fertilizer prior to planting. Mix your compost and fertilizer into the top 6 inches of your garden bed. Slightly acidic soil with a pH between 6.0 and 7.5 is ideal. A home soil test can help you determine what your garden soil needs.
3. Time It Right
Choosing when to plant sunflower seeds requires a bit of waiting. Plant sunflowers in late spring, once the ground is nice and warm. Most sunflowers germinate when soil has reached 70 to 85 degrees F. The best time to plant sunflowers is just before the soil reaches this temperature. Look for a ground temp of between 60 to 70 degrees. For most areas, this will be approximately three weeks after the last frost. Planting sunflowers indoors gives you a head start on the growing season. Simply tuck the seeds into peat pots around the time of your last spring frost. They should be the right size for transplant once the soil is the appropriate temperature.
4. Plant the Seeds
Different sunflowers require different planting depths and spacing. How to grow sunflowers from seed and how deep to plant sunflower seeds depends on your specific sunflower cultivar. In general, plant sunflower seeds at least 1/2 inch deep. Space seeds 6 inches apart. If planting in rows, you’ll want 2 to 3 feet between each row. Plants should be thinned out in a few weeks to the proper spacing. If soil temperatures are just right, sunflower seedlings will sprout up in 10 to 14 days.
Growing sunflower seeds requires space. To start sunflowers indoors, plant three seeds per each 3- to 4-inch peat pot. A soilless planting media will give you the best drainage. Indoor germination usually happens in 6 to 10 days. You can enjoy continuous blooms through summer by planting seeds every couple of weeks. With consecutive plantings, you’ll have beautiful sunflower blooms right up until the first frost of fall.
5. Give Plenty of Moisture
Because sunflower seeds contain large amounts of natural oil, they require a lot of water for germination. After planting, water the ground thoroughly. Keep the soil moist with frequent, light watering until germination occurs. If starting indoors, cover your pots with clear plastic wrap to keep in moisture. Remove the plastic as soon as the seeds sprout.
6. Thin the Seedlings
Once the sunflower seedlings have their first set of true leaves, thin the seedlings to the recommended row spacing for your variety. Small sunflowers may require only 6 inches between each plant, while large varieties might need up to 3 feet. Closer spacings are possible for garden aesthetics, but crowded plants will produce smaller flowers.
Indoor sunflower seedlings should be reduced to one seedling per cup. Simply choose the strongest sunflower and pinch back the others.