How to Propagate Petunias from Seed

30.06.2023 - 01:07 / gardenerspath.com / Kristine Lofgren

Petunias are everywhere. They tumble out of hanging baskets, flank doorways in pots, and fill flower beds across the world.

They bloom all summer long, come in a massive range of colors and flower shapes, and are a cinch to grow, so it’s no wonder people love them.

We link to vendors to help you find relevant products. If you buy from one of our links, we may earn a commission.

Sure, you can buy them at nearly any nursery and even many grocery stores in the spring and summer.

But there’s no reason not to propagate plants by sowing seed yourself. It’s cheap, easy, and you can often find hybrids available that you can’t track down as starts from the nursery.

Before we get our hands dirty, here’s the lowdown on what we’ll be discussing:

To understand how to propagate plants, it helps to know where petunias grow in the wild.

They’re from warm regions of South America and they can be cultivated as perennials in USDA Hardiness Zones 9 to 11.

Most gardeners grow them as annuals because the climate in their region isn’t right for petunias year-round.

With that in mind, let’s start our germinating adventures…

If you’re going to start petunias from seed, it’s best to start them indoors. They need a long time, over two months, to germinate and mature enough to transplant outside.

Look at the last predicted frost date in your area and count back 10 or 11 weeks. For most people in North America, that’s going to be in February or March. That’s when you need to sow your seeds.

You can also opt to start the plants outdoors if you live in a region with long, mild springs. So long as there is no chance of frost and the soil temperatures are above 60°F, you can sow in place.

Petunia seeds need