When to Plant Sunflowers (and When You Shouldn't), According to Gardening Experts

Sunflowers are iconic for a reason. Their cheerful yellow blooms add a splash of color to any yard, and they attract many beneficial pollinators, like bees and butterflies. However, while you may want your backyard to look like a Van Gogh painting, don't rush into it—timing is key when it comes to planting sunflowers.

So when is the best time to start adding sunflowers to your garden? No one knows better than the experts—here, we spoke to them about their best practices for planting these elegant yellow blooms.

When to Plant Sunflowers

The best time to plant sunflowers is in early spring after the risk of frost has passed. "In most areas, this would be around late April to mid-May," says Alexander Betz, landscape designer and founder of Plant By Number. The soil temperature should be between 50 and 60 degrees Fahrenheit.

"You can also plant throughout the summer if you have several varieties with different days to maturity," adds Shauna Moore, director of horticulture at the Brooklyn Botanic Garden. "If you want to plant for succession, you can seed every 7 to 10 days for single-stem sunflowers and every 2 to 4 weeks for the branching types of sunflowers."

Planting during the morning or late afternoon will help reduce stress on the seeds, adds Betz, and prevent the soil from drying out too quickly.

When Not to Plant Sunflowers

Planting sunflowers too early or too late in the season can lead to a whole host of problems. These blooms are very sensitive to the cold, so they won't fare well if exposed to frost or cold soil. "It slows growth and increases the risk of disease," says Betz. So while it's important to plant them earlier in the spring, make sure it's not too early—and keep tabs on the last frost dates for your region.

Moore also notes that sunflowers generally take about 80 to 95 days to mature, which is important to keep in mind when planting. "Never plant [them] late in summer," she notes. "You risk having flowers before the first frost."

How to Plant Sunflowers

The experts we spoke to all recommend planting sunflower seeds rather than starters. "Starters have a taproot, which shouldn't be disturbed once it starts growing," says gardening author and editor Mary Schier.

Plant your sunflower seeds about 1 inch deep in the soil and about 6 inches apart from one another. "Choose an open and bright spot where they won't shade out your smaller plants," says Betz. "It's best to plant them along the northern or eastern edges of your garden."

How to Care for Sunflowers

As their name would suggest, sunflowers need plenty of full sun to thrive. Soil should ideally be warm (about 60 degrees Fahrenheit) and well-draining.

"After planting, keep the soil consistently moist, but not waterlogged," says Betz. "Do this until the seeds are established. Thin the seedlings to proper spacing once they’re a few inches tall." Once their second set of leaves emerges from the soil, Moore recommends using "a touch of organic fertilizer."

One big problem to keep an eye out for? Garden intruders that may want to snack on your sunflowers.

"I've had a lot of problems with deer chomping the tops of my sunflowers when they're about a foot tall ... very discouraging," says Schier. "Cover the plants with netting or protect them with fencing for better results."