How to Grow Petunias

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Last Reviewed:May 24, 2023 by Gabrielle Marks

How to Grow Petunias

Petunias are one of the most popular plants found in flower gardens. Learning how to grow petunias isn’t difficult. Follow these tips for a healthy garden.

Choosing Your Petunias

Petunias come in hundreds of varieties, with the biggest differences being the flower size and the requirements for growing. When deciding which variety of petunias you want, you need to take into consideration available space and whether you are planning a container garden.

Requirements for Petunias

Petunias require plenty of light. This will need to be taken into account when selecting where they are going to be planted. The soil needs to have good drainage to prevent root rot. If you are concerned about soil nutrients, add organic matter like sphagnum moss to nourish your plants.

Fertilizer

If you plan to use fertilizer, use a liquid fertilizer and add it to your routine every three weeks. If you are growing a type of petunia that spreads out, also known as a groundcover, you must fertilize once per week. When planting your petunias, use a balanced fertilizer, such as 8-8-8 or 12-12-12, and work it into the soil well. The ratio should be about 2 pounds of fertilizer per one hundred square feet.

Starting Petunias

For the beginning gardener, starting petunias from seeds can be challenging. Until you are more comfortable with the process, you may wish to purchase seedlings or full-grown plants and transplant them when conditions are right. Petunia seeds are very lightweight, blow away easily, and require a lot of light to germinate. This can be challenging since they must be started in March for the best results. Spread the seeds out on a layer of sphagnum moss or potting soil and mist to drive the seeds into the soil. You may also push them in gently with your fingers. Seedlings may be transplanted when they have three true leaves.