How to Save Petunia Seeds For Next Year

You can save petunia seeds if you allow them to dry out on the plant and collect and store them correctly for planting the following season. Wendy Moulton will take you through the simple steps to do this and enjoy free petunias in the next couple of seasons.

Written by Wendy Moulton Horticulture review by Sarah Jay Last updated: September 4, 2024 | 4 min read

A close-up of dried black flower buds scattered on a smooth, dark surface.

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The varieties and colors of petunias are vast and include four main types: grandiflora, multiflora, millifora, and trailing ground cover. The colors range from pure white to the brightest pink, all colors between and picotee too.

With so many choices available, it makes sense to grow the ones that perform well in your garden and the colors you prefer the following season. The best way to do that is to save the seed for sowing indoors before the last frost date or outdoors after the chance of frost has passed in spring.

Can You Save Petunia Seeds For Next Year?

A person's hand delicately holding a tiny golden bud on the tip of their finger, ready for planting. — You can indeed save seed for sowing the following year, but there may be new hybrids that are sterile.

Petunias grow very easily from seed, and just a few pods will yield the same number of seeds as a packet you buy from the store. You can indeed save some for sowing the following year, but there may be new hybrids that are sterile. These are often the ‘self-cleaning’ varieties that the growers will usually reveal on the growing instructions of the plant. If you are unsure, save some seed to try the following year, and then keep notes on what works and what doesn’t.

These sterile versions are propagated vegetatively in the gardening industry and sold in garden centers and nurseries as large plants or seedlings.

When to Collect

A small plastic vial filled with golden buds resting on a bed of dark soil inside a container. — The end of summer and autumn are the main times to harvest pods.

Petunias will flower from spring and all through summer in the right conditions, with regular feeding and deadheading. This depends on the climate in your area and the types of petunias, but as a general rule, we can rely on the end of summer and autumn to harvest pods.

When the first frosts come in the fall, they will die back. The temptation is to cut them back to make them look a bit neater, but this will prevent the pods from forming, so if you are planning on saving seed, it’s best to continue watering them and leave them to dry out.

What You’ll Need

A pair of hands carefully pouring golden buds into small circular pots filled with rich soil, surrounded by gardening tools. — Gather a piece of white paper, an envelope or glass jar, and a marker to write the variety and date.

All you need to save petunia seeds for the following season is a petunia plant at the end of the flowering season, a piece of white paper, an envelope or glass jar, and a marker to write the variety and date. You can make an envelope out of a bit of scrap paper by folding it into an envelope. There are many ways to do this without needing tape or glue. You can also use glass jars with lids for storage.

How to Save Petunia Seeds

A close-up of a flowering plant in a container, with vibrant pink blooms and some wilting foliage in need of care. — Tubular flowers will start from this point and keep the ovary safe in the base until it is fertilized.

The flower structure of a petunia helps identify more about saving seeds. The stem is attached to the calyx, the leafy bit at the bottom of the flower that protects the ovary, which is at the base of the flower and from which the pods will form. The tubular flower will start from this point and keep the ovary safe in the base until it is fertilized.

Step 1: Monitor

A flowering plant outdoors with white blossoms starting to dry and wither, indicating the end of its blooming period. — Petals will become brown and fall off, leaving the base of the flower on the plant.

The flowers need to die back, and the pods need to be very brown and crisp for you to harvest the pods. The petals will become brown and fall off, leaving the base of the flower on the plant. This is where the seeds will be produced.

Step 2: Wait

A cluster of dried brown buds clinging to the branches of a plant, surrounded by dry foliage. — If they still have some give, let them dry out a few more days.

Check for moisture and ensure pods are crispy enough to cut off. If they still have some give, let them dry out a few more days. If the weather is rainy, they can be brought inside or undercover to dry out.

Step 3: Harvest

A person using pruning shears to clip away dried brown buds from a green plant stem. — Remember that each pod will contain at least 20 seeds.

Cut the pods off the plant. Remember that each pod will contain at least 20 seeds. Fold a piece of white paper in half and use your fingernails to crack open the pods, allowing them to spill onto the paper. The small black seeds are easier to see on white paper.

Step 4: Pack and Mark

A brown envelope partially open, spilling out tiny golden buds onto a wooden surface. — Close the envelope and mark the outside with the name petunia, the variety, color, and the date.

Once they have all been unearthed, discard the husks and fold the paper to help pour the tiny seed into the envelope or jar like a funnel. Close the envelope and mark the outside with the name petunia, the variety, color, and the date. You can also add what type of petunia to take out the guesswork the next year when you are ready to sow, so you know what form they will take and better position them in the garden or into containers.

Labelling is a vital step to help identify the variety when you sow it in spring. The date will show that you can use it for at least two years from the date before it becomes unviable.

Storing Petunia Seeds

Several neatly wrapped brown envelopes, each tied with blue string, containing tiny golden buds. — The paper allows them to breathe a little in case they are not dry.

Do not store seeds in plastic if they are not totally dry. Paper is better, and you can fold an envelope with a scrap piece of paper. The paper allows them to breathe a little in case they are not dry. You can also store in glass jars or tins. If you have some water-absorbing granules, then all the better to keep moisture from disturbing your valuable propagation material. Make sure the seals on the tins or jars are airtight.

To store for longer time periods, place them in a waterproof container in a dry, cool area. Glass jars must be kept out of the sun, or they will not be viable long term. The temperature should not reach above 90°F (32°C), or the germination rates may be reduced.

When you are thinking about how many pods to harvest, remember that you can share your petunias, too. Join a swap club to swap seeds with others, or start a plant library at your local community center. It’s a fun way to share with others and get some excellent propagation material for your own garden.