What To Know About Growing Sunflowers From Seeds

Sunflowers grow best when you sow seeds directly in the garden. Here are a few tips to keep in mind to ensure success.

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I once planted a flower bed with only sunflowers, choosing 10 varieties with varying heights and colors. It was quite a stunning garden, attracting pollinators first, then birds and squirrels when the seeds ripened.

Choosing the Best Type of Sunflowers for Your Yard

Sunflowers come in various heights, bloom sizes and colors, all easy to grow from seed. Some sunflowers to consider include:

  • Mammoth Grey Stripe: The classic, with a big yellow flower on top of a nine-to-12-foot-tall stem.
  • Teddy Bear: Grows only three to four feet tall, with big double flowers resembling pom-poms.
  • Chocolate Cherry: Grows six to seven feet tall with dark reddish brown flowers.
  • Sunray Yellow Hybrid: Great for containers, this tops out at 18 inches or so, with several branches and lots of blooms.
  • Ring of Fire: Bi-colored petals are red closer to the center and yellow on the tips, on five-foot stems.

When choosing sunflower varieties for your garden, remember taller varieties may need to be staked.

Planting Sunflower Seeds

Sunflower seeds are readily available. You can pick up a packet of seeds for just a few dollars at most garden centers. I’ve even gotten free sunflower seeds from my local library’s seed library.

When To Plant Sunflower Seeds

Plant in the spring once your garden is frost-free. Sunflowers will not tolerate frost and germinate best in warmer soils, so don’t jump the gun.

In areas of the country that don’t get frost, sunflowers are still generally grown from spring through summer.

If you’re concerned you don’t have a long enough growing season for sunflowers to bloom, check the seed packet to see how long on average it takes that variety to flower. If the number of days is shorter than your growing season, start seeds indoors a few weeks before your frost-free date.

How To Plant Sunflower Seeds

Sowing seeds directly in the garden

Sunflowers don’t like to be disturbed, so it’s best to leave them where you sow them.

  • Cultivate the soil a few inches deep and remove weeds.
  • Sow seeds at the depth and spacing noted on the seed packet. If there are no instructions, plant about an inch deep.
  • Sow two or three seeds together, then thin to one seedling once the second set of leaves develops. Be careful not to disturb the roots when removing the extra seedlings. (To prevent this, I cut off extra seedlings instead of pulling them out.)

Sowing seeds indoors

Here’s how to start them:

  • Plant two or three seeds in biodegradable pots with a seed starting mix.
  • Keep soil evenly moist until seeds germinate.
  • Thin out to one seedling per pot once seedlings begin to develop a second set of leaves.
  • Keep seedlings under lights or near a bright window to avoid getting too leggy.
  • Harden off seedlings before planting them outside.
  • Plant in full sun and space them as far apart as instructed on the seed packet.

Whether starting seeds indoors or directly in the garden, choose a location with well-drained soil and full sun. Tall sunflowers can create a lot of shade, so plant them on the north side of full-sun flower beds to avoid shading out other flowers.

Sunflower Care


Sunflowers grow well with about an inch of rain a week, from rain or supplemental watering.


Overcrowded sunflowers won’t grow as well, so space seedlings out as directed on the packet. Some smaller sunflowers may grow well a foot apart. Larger sunflowers will need up to two feet between them.


If you often experience strong winds or storms, consider staking taller varieties of sunflowers to give them extra support. Put stakes in place before planting to avoid disturbing the seedlings later. Tie stems to stakes for support.


Sunflowers can benefit from additional fertilizer, especially if grown in a container. Use a general purpose fertilizer and follow the instructions on the label.

Controlling pests and diseases

Sunflowers don’t get too many pests or diseases, though rabbits or birds may eat new seedlings as they emerge. If this is a problem in your garden, start seedlings indoors. Once planted in the garden, protect seedlings with a row covering until they’ve grown larger than the edible stage.

Harvesting Sunflower Seeds

You can harvest sunflower seeds for bird or squirrel feed, or to eat yourself. Although technically all sunflower seeds are edible, we mostly eat the seeds from Helianthus annuus, the common sunflower.

When the flower head droops and the back of the flower turns yellow, the seeds are usually dry enough to harvest. If you’re concerned about birds getting to the seeds first, cover the flower head with cheesecloth or a paper bag. Or cut the flowers off, leaving a one-foot stem, and hang them where they can finish drying.

Check your local cooperative extension service for instructions on how to roast sunflower seeds, or use this information from Kansas State Research and Extension.

Carol J. Michel
Carol J. Michel is an award-winning author of several books including five gardening humor books and one children's book. As the holder of degrees from Purdue University in both horticulture and computer technology, she spent over three decades making a living in healthcare IT while making a life in her garden. She started writing about gardening on her blog called May Dreams Gardens which lead to numerous magazine articles, her books, and a podcast called The Gardenangelists. She was recently named a GardenComm Fellow by Garden Communicators International.