How to Grow Sunflowers

The hardest thing about knowing how to grow sunflowers (Helianthus annuus) is deciding which ones to grow. Nearly fail-proof, they’re a great project for kids and new gardeners. Besides the classic golden yellow flowers, colors range from deep burgundy, russet and chocolate to lemony yellow, blazing bicolors and pale vanilla. There’s a sunflower for every garden, whether 15-foot giants or tiny dwarfs for balcony pots.

PREPPING YOUR SUNFLOWER PATCH

Sunflowers grow a long central taproot that doesn’t like to be disturbed. Rather than starting seeds indoors, sow directly to your garden. Sunflowers grow bigger and stronger in return. Any soil type is fine, as long as it has good drainage. Pick a site that gets at least six to eight hours of direct daily sun — the more, the better.

For best results, cover the area with 3 to 4 inches of compost, and work it into the soil to create a loose, fertile home for roots. For smaller varieties, no fertilizer is needed. Bigger varieties benefit from a boost. Apply a balanced, slow-release fertilizer — one with all three numbers the same. Work it into the top few inches of your sunflower bed to provide season-long nutrition.

PLANTING YOUR SUNFLOWERS

Sunflower seedlings resist some cold, but for most areas, wait until at least two weeks before your last expected spring frost before you sow. As you plan, think how tall your sunflowers may grow and where their shadows will fall. Plant the tallest varieties to the north side of shorter plants, so everyone ends up with sun.

For rows, make a shallow trench and plant seeds 1 to 2 inches deep and 6 inches apart. Cover the seeds with soil, and keep them well watered. You’ll see sprouts in seven to 10 days. For continuous blooms, sow a row every two to three weeks; you’ll have cheery blooms until frost. Most sunflowers mature in 80 to 120 days.

CULTIVATING YOUR SUNFLOWER CROP

Sunflowers don’t like competition from weeds — or other sunflowers. Apply 2 to 3 inches of mulch to keep weeds down. Once seedlings begin to grow, thin them to 2 feet apart for large varieties and 1 to 1 1/2 feet apart for dwarf and medium types. The more room they have, the larger and stronger they’ll grow. If growing smaller varieties for cutting or in pots, crowding is okay. Space seeds 2 to 6 inches apart for thinner stems and smaller, but beautiful, flowers.

Sunflowers tolerate drought once established, but moisture is critical between three weeks before and three weeks after flowering starts. Water plants deeply and thoroughly. Then let soil dry before watering again. This helps roots grow deep and strong. If growing multi-head types or giants, heads can get heavy. Stake large sunflowers, so heads don’t snap in winds or heavy rains.

HARVESTING YOUR SUNFLOWERS

If you want seeds, think ahead and protect seed heads from birds. Cover them with mesh bags or other protective netting. Seeds are ready once the back of the flower head turns from green to yellow and the tiny petals dry to expose brown seeds. Usually the head begins to droop, too. Cut the head off and hang it upside down in a cool spot with good air circulation, and let it dry fully. Then collect your seeds.

Sunflowers are packed with protein, iron, potassium and vitamins B and E. Toast the seeds in a dry skillet over medium heat for 10 to 15 minutes, or oven toast them on a cookie sheet or shallow pan for about 10 minutes at 350 degrees Fahrenheit. For rich, slow-roasted flavor, soak the seeds in strong salt water overnight and roast them at 200 degrees for 2 1/2 to 3 hours until crisp. Enjoy!

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