Last Updated on May 14, 2025 by Thompson & Morgan Horticultural Team

This climbing petunia has been trained up an obelisk to create a spectacular focal point
Image: T&M

Here you’ll find the best expert content on raising petunia seeds or growing petunia plug plants. We’ve scoured the web to bring you insights from the experts who know petunias best – the experienced, green-fingered garden bloggers who love to grow them. Here’s a wealth of information and advice to help you successfully grow your own perfect petunias.

This article was reviewed by T&M’s horticultural team and updated on 22 February 2024.

Sow petunia seeds in March for glorious summer bedding

These unique double flowered petunias are easy to grow from seed
Image: Petunia grandiflora ‘Double Cascade Burgundy Plum Vein’ F1 Hybrid from Thompson & Morgan

It’s not true that Petunias are difficult to grow from seed, say the expert horticulturalists here at Thompson & Morgan’s blog. In fact, like any seed, they just need the right conditions in which to thrive, and timing is key to success. If you’re looking to grow glorious Petunias from seed to use as bedding plants or for containers and hanging baskets, just be sure to sow 12 weeks before you expect the last of the winter frosts to have passed – sowing indoors in March for June planting out is a safe bet.

Mix tiny petunia seeds with sand for easy sowing

Sprinkle the tiny seeds as thinly as you can
Image: In the garden with Eli and Kate

Don’t be put off growing petunias from seed says Eli at In the garden with Eli and Kate. She explains that the biggest problem is the very tiny seeds which can be difficult to handle, but that needn’t stop you. Check out Eli’s blog post and YouTube video for well-presented, clear advice on growing petunias this way. One method for handling tiny seeds, Eli explains, is to mix them with a little pale sand – that way, when you sprinkle them over your compost, you can see where you’ve been, ensuring even coverage.

Use a modular seed tray to grow on your seedlings

Pot your seedlings on after about 30 days when each one has 4-5 leaves
Image: Gardening For Beginners

If you don’t usually grow your petunias from seed and you’re looking for a few practical tips, Ray’s video at Gardening For Beginners is the place to start. From sowing the tiny seeds to seeing them flowering in the hanging basket, this start to finish guide to growing petunias from seed tells you everything you need to know. Ray sows his petunia seeds into drills before covering the tray with clear plastic and leaving in a warm place to germinate. About 30 days later, the seedlings should have 4-5 leaves and be ready to pot out.

Give your petunias plenty of sunshine

Inject tropical pizzazz into displays with distinctive Petunia ‘Amazonas Plum Cockatoo’
Image: Petunia ‘Amazonas Plum Cockatoo’ from Thompson & Morgan

“The secret of good petunias is plenty of strong light,” says Tejvan at Gardeners Tips. Originally from South America, “petunias are from the family Solanaceae that includes tobacco, cape gooseberries, tomatoes, deadly nightshades, potatoes and chilli peppers.” If you’re new to growing petunias and would like a succinct rundown of the different varieties and how to grow them, this is the place for you. Looking for a reliable Petunia? Tejvan recommends giving ‘Surfinia’ a try.

Choose a multiflora petunia for resilient blooms

Multiflora petunia blooms are typically more weather resistant
Image: Petunia ‘Frills & Spills’™ Mixed’ Pre-Planted Basket from Thompson & Morgan

Did you know there are different types of petunia? Multiflora types are more resilient to wind and rain than the big, lavish grandiflora petunias, making them a wise choice for an exposed window box or a mixed container planting marking an entryway. A fantastic example of a multiflora is petunia ‘Priscilla’, bred to thrive in our British climate with its mauve scented double flowers. Find out which type is right for you in our article ‘How to Grow Petunias’ over at Thompson and Morgan.

Look for unique markings and striking colours

‘Amore King of Hearts’ has five red ‘hearts’ on each bloom
Image: Petunia ‘Amore Trio Collection’ from Thompson & Morgan

“Not only are the flowers cheerfully fluorescent, but they also have a heart on the tip of every petal!,” says Michael Perry, aka Mr Plant Geek. He’s talking about the Petunia ‘Amore’ series; “how devilishly romantic!” Just one of his top five most fascinating petunias, check out Michael’s post to see the rest of his favourites. This article is a great read for anyone pondering the weighty question of which petunias to grow next season – especially if you’re looking for something a little different.

Try modern petunias like the spectacular ‘Night Sky’

Petunia ‘Night Sky’ is a stunning petunia
Image: @kath_brewer

See one of the most stunning petunias ever developed at its magical best, courtesy of Instagrammer @kath_brewer. We think you’ll agree her photo of Petunia ‘Night Sky’, is an absolute corker. She says she couldn’t resist capturing the flowers in all their glory amid the soft glow of the evening light. A great pic from a fabulous photographer, this is an Instagram account well worth a follow.

Create a potted flower display with pretty petunias

Beautiful containers make you happy to be home
Image: Thompson & Morgan

As well as her fabulous petunias, Denise from @my_little_plot treats her visitors to a riotous display of potted canna lilies, dahlias, geraniums, swan river daisies and dianthus at the entrance to her home. In June, they’re not quite in full bloom but still add a lovely green softness to her outdoor space. Denise’s tip for creating your own potted plant display is to save money on the pots by using cheap and cheerful plastic ones because, “once the plants start spilling over them you can’t tell what they are!” Follow on her Insta for more clever hacks!

Fill hanging baskets with petunias for vibrant kerb appeal

Petunia ‘Surfinia’ Collection pre-planted basket from Thompson & Morgan
Image: Yuriy Chertok/Shutterstock

If you’re wondering what to grow in your hanging baskets, expert gardener and blogger, John Moore of Pyracantha recommends giving Petunias a try. He says trailing varieties are ideal to grow this way provided you “find a spot for your basket that will hang in exposed sunlight all day as they like plenty of sunshine.” He recommends you go for a big hanging basket of at least 14” diameter and, for best results, fill it with quality compost that retains moisture effectively.

Use a limited colour palette for elegant displays

This scented hanging basket is positioned by the door so the fragrance can be enjoyed
Image: Veg Plotting

Lots of people like to experiment with different varieties, says Michelle of Veg Plotting, but having found a combination of petunias that grow reliably in British weather, she’s sticking with her favourite Surfinia ‘Purple Vein’ and Petunia ‘Priscilla’, beautifully set off by a trailing bacopa. If you fancy a go at creating a hanging basket (which Michelle says is akin to a horticultural “horn of plenty”) she offers some excellent tips on hardening off, watering and feeding.

Feed petunias sparingly for more flowers

Brighten up your front entrance with hanging baskets overflowing with petunias
Image: Petunia ‘Frills & Spills™ Cherry Ripple’ from T&M

Now for some petunia trivia courtesy of prolific and supremely knowledgeable gardening blogger, Mandy of MandyCanUDigIt. Did you know, for example, that the plant was named in “1789 by French botanist Antoine Laurent de Jussieu?” Head over to Mandy’s blog for more interesting Petunia facts plus tips on how to feed your petunias to avoid excessive foliage production at the expense of the flowers.

Deadhead petunias regularly to encourage flowering

Petunias make an excellent bedding plant as part of your summer display
Image: Petunia ‘Frenzy Mixed’ F1 Hybrid from T&M

If you’re looking for an overview of how Petunias fit into your summer bedding mix, Carol Bartlett of The Sunday Gardener offers an excellent article in which she compares the different options available to you. She says the soft pastel colours of petunias make them excellent bedding plants, and regular deadheading prevents them setting seed, forcing them to produce even more beautiful blooms that should last right through to autumn.

Take petunia cuttings for even more plants

Taking cuttings is easy when someone shows you how
Image: altana-studio/Shutterstock

Taking cuttings from your petunias is a great way to get more plants for your money, especially if you’re growing from seed. The YouTube channel, Happy Sowing Happy Growing, provides an excellent short video which shows you exactly where to snip your petunias and how to pot them so they stand a good chance of rooting. A very straightforward process, all you need is some quality multipurpose compost and a pair of sharp scissors.

Save your petunia seeds for next year

 ‘Amore Queen of Hearts’ has distinct red and yellow blooms
Image: Petunia ‘Amore Trio Collection’ from Thompson & Morgan

Thrifty gardener Tami loves petunias for their gorgeous evening scent, and uses them to fill gaps all over her garden. At the end of summer, she carefully fills little containers with saved petunia seeds to sow the following spring. This gives her fabulous summer blooms for free! See just how tiny petunia seeds are and photos showing Tami’s technique at her Instagram: @garden_of_riley.

We hope you’ve found our collection of petunia content helpful and informative. For more information and advice on petunias, visit our dedicated hub page.

Sophie Essex

Sophie Essex is a freelance garden writer with a passion for horticulture and environmental conservation. With a BSc in Botany/Plant Biology from the University of Plymouth, she further honed her expertise through a Masters of Science in Biodiversity and Taxonomy of Plants from The University of Edinburgh.

Sophie has also worked as a professional gardener and landscaper, showcasing her practical skills by transforming outdoor spaces. Her commitment to fieldwork is further evident in her acquisition of a Certificate in Field Botany from the Royal Botanic Garden Edinburgh, and over the years, she has interned at the Eden Project, Cornwall, the National Trust for Scotland and the Royal Botanic Garden Edinburgh. Find more information about Sophie over at LinkedIn.