How to grow petunias

Nothing beats petunias for bringing stunning summer colour to pots and baskets. There has been lots of breeding, producing ever-more colourful varieties, many of which don’t need deadheading, and are resistant to the wind and rain.

Some are trailing, making them ideal for baskets, and others have a more upright habit. There is a bewildering choice of colours and patterns to choose from, so we’ve found the best varieties to add a bright splash of colour to your patio.

Key facts

PLANT TYPE Tender annual

POSITION Full or part sun

SOIL Well-drained and fertile

How to grow petunias: month by month

Best petunia varieties

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How we test petunias

We chose 17 varieties of single petunias including examples of new breeding and old favourites.

We planted three plugs of each variety in a nine-litre pot and also into a 30cm basket with our Best Buy compost for containers mixed with Best Buy controlled-release fertiliser.

We put them outside once all danger of frost had passed and kept them watered with an auto-irrigation system.

We monitored them throughout the summer to see how good a display each variety gave and how long they flowered for. If any plants looked a bit pale or stopped flowering, we topped them up with a liquid feed in August.

We ended the trial in October.

Caring for your plants

Planting

When your petunias plugs arrive you can plant them straight into pots or baskets, mixing in some controlled-release fertiliser with a Best Buy compost for containers.

These can be grown in a light, frost-free place until you’re ready to move them outdoors when the danger of frost has passed. They do best in a bright, sunny spot but will tolerate light shade.

Watering 

Petunias are drought-tolerant, but keep them well-watered as they will dry out quickly in pots and baskets.

Deadheading

Remove the faded flowers to the base of their stems to prolong the flowering season. 

Feeding

Controlled-release feed usually runs out towards the end of summer, so when this happens start giving a liquid feed once a week to keep the display going for longer. 

Common growing problems

Greenfly

Squash any aphids before they can develop into larger infestations that may cause damage

Read more about greenfly.

Slugs and snails

Slugs and snails can nibble holes in your plants. Scatter organic slug pellets sparingly around the plants or remove any slugs and snails you see.

Read more about slugs and snails.

Powdery mildew

Petunias can be prone to the white coating of mildew, so make sure you keep them well-watered to avoid stressing the plant.

Read more about powdery mildew.