How to Care for Petunia Flowers

Updated April 17, 2017

Petunias are quite hardy annual flowers that are usually used as edges and borders in gardens. They are also very attractive in window boxes and hanging baskets. Petunias come in a variety of beautiful colours and their edges vary from smooth to ruffled. Some are very short and used as ground cover, and some can grow as tall as two feet. The flower looks like a trumpet and has a mild scent like cinnamon. They attract hummingbirds and if cared for can last from spring to the first frost of winter. In milder climates they may be grown year round.

Before planting petunias, make sure there is no more risk of frost. The ground temperature is best at around 15.6 degrees C. You can start them from seeds indoors approximately ten weeks before they are transplanted into your garden space.

Petunias like being in the sun or partial shade. Choose a piece of ground that will receive sun for at least half of the day. Also be sure that the soil can hold the moisture by adding mulch. Petunias do better if there is some organic matter mixed in with the soil, but be sure to work it into the soil well. After the flowers are tall enough, you can add another layer of grass clippings or bark.

When planting, space the plants at least 4 to 6 inches apart for minatures and 12 inches apart for the larger plants. Use commercial fertiliser about once a month . Hanging plants may need more fertiliser to support them. Keep fertiliser off the actual flower to avoid burning them. Peat moss can be used to neutralise the soil if it is too salty.

As the petunias grow, they might get spindly or leggy. You can pinch them off if they show discolouration or look disfigured. You will want to spray if you see pests like aphids or cutworms. If the leaves turn black, you may need to use a fungicide on them. If you maintain the proper moisture and temperature, you should not have many problems.


If you put petunias in a basket, only use four plants per container as they spread four inches in every direction.

Things You'll Need

  • Petunia seeds or seedlings
  • A plot of land that receives sunlight at least part of the day
  • Mulch and/or peat moss
  • Fertiliser
  • Water
  • Organic matter
  • Pesticide
  • Fungicide
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About the Author

Ruth Kongaika began writing professionally in 2008. She has been working as a freelance writer for various websites, specializing in health, travel and technology. Kongaika works for the School of Education at Brigham Young University's Hawaii campus, where she received her Bachelor of Fine Arts in art.