How to Grow and Care for Petunias

Add a splash of colour to your garden beds or containers with a vibrant Petunias. With their prolific blooms and wide variety of hues, Petunias are a popular choice for transforming any outdoor space into a blooming paradise!

Petunias come in a full spectrum of colors and shapes, making these unfussy blooms a popular choice for summer containers and garden beds. What’s more, petunias are pollinator-friendly and grow quickly; once their seeds germinate, you can expect to see full-size plants in just 12 weeks. With adequate sunlight and well-draining soil, petunias can bloom from spring until fall, providing you with multiple seasons of interest. To ensure this annual flower thrives in your garden, we spoke to experts who explain how to grow and care for petunias.

How to Plant Petunias

You can either plant petunias from seed or from container.

From Seed

To grow petunias from seed, start at least 10 to 12 weeks before your last spring frost, says Eric Groft, CEO and director of Ovsla.

Spread seeds on top of a moist-starting mix; avoid submerging them in soil.
Cover your container with a clear lid to keep seedlings warm.
Keep the soil moist and provide bright light.
Once the seeds germinate, remove the plastic cover.
Once you see one to two sets of true leaves, harden them off and transplant outdoors.

Mature Plants

Plant container-grown petunias outdoors after the threat of frost has passed, says Carrie Spoonemore, co-creator of Park Seed’s From Seed to Spoon app.

  • Choose a sunny location with well-drained soil.
  • Dig a hole twice as wide as the container and at the same depth.
  • Gently remove the plant from the container, loosen the root ball, and place it in the hole.
  • Space plants 12 to 18 inches apart, depending on the variety and tag instructions.
  • Water thoroughly after planting and keep the soil consistently moist.

How to Care for Petunias

Petunias are easy to care for, but there are some things to keep in mind to ensure they thrive in your garden.


Petunias require a minimum of six hours of direct sunlight per day. But there are varieties that can thrive with some shade, which is beneficial during the peak of summer when UV rays are strong.


Water petunias regularly so the soil is moist but not waterlogged. About 1 to 2 inches of water (including rainfall) a week is sufficient. Note that plants growing in containers may require more supplemental water, says Groft.


Petunias need well-draining soil that is rich in organic matter, says Spoonemore. These plants won’t survive in soggy soil, which may lead to root rot.


Feed petunias with a balanced liquid fertilizer at the time of planting. Once established, use a balanced, water-soluble fertilizer designed for flowering plants every two to three weeks during the growing season, says Spoonemore.