Planting Petunias in Spring | Soil Preparation, Fertilizer and Growing Seeds

Plant petunias in spring when the chance of frost has passed. Petunias grow well in garden beds or pots but look out for pests. Spring is the prime time for pest attack including aphids, snails and slugs. Plant petunias into well-draining soil and water them well until they establish.

This article will explore all you need to know about planting petunias in spring. This includes how to prepare the soil, where to plant petunias, how to fertilize them and when to start seeds.

How to prepare the soil for planting petunias in spring

Preparing the soil to plant petunia seedlings is essential because they need well-draining soil to thrive. Prepare raised garden beds or in-ground gardens by mixing through compost and aged cow manure.

This will lighten the soil and allow the roots to grow strong and avoid rot. If you are planting petunias in a pot, choose a premium potting soil. This will have added fertilizer that will feed the new seedlings for 3 months.

If you have worm castings from your worm farm, mix through a few scoops to add nutrients and organic matter to the soil.

Where to plant petunias in spring

Petunias will produce the most flowers if they are planted in a position that gets at least 6 hours of sunlight. They will grow quicker and flower sooner. You can move potted petunias around to chase the sun or find a sunny position in an open garden bed.

If you have poor or shallow soil, plant petunias in a pot and place it in your garden bed to brighten up the area. This also works well if you have lots of pests attacking your petunias. Mine were being eaten overnight by slugs so I lifted them up and put them in pots. This helped to prevent pest attack as they are not as easy to reach.

Petunias grow well in raised garden beds, pots or in the ground. Just make sure you improve the soil before planting petunias. My petunias have grown rapidly over spring reaching over 4 feet wide. These are large, creeping petunias which are great for covering a large space and preventing weed growth.   

How to fertilize petunias in spring

Fertilize petunias 4 weeks after planting them out. Give them a small handful of pelleted chicken manure. This is a gentle fertilizer that will help the plant to establish. This will give you a large, healthy green plant that will start to produce flowers by the middle of Spring.

Water the plants with liquid seaweed at the start of every month. This will help the roots to strengthen and will allow the plant to produce flowers for longer. Petunias that are well cared for can flower all the way through summer and into fall.

Once fall arrives, these annual plants will turn brown and die off. Pull them out of the end of the season or snip them off at ground level. You can leave the old roots in the ground and they will break down.

When to plant petunia seeds ready for spring

Plant petunia seeds 8 weeks before the start of spring. You will need to raise them in a protected area if you live in a cooler area or get frosts. Plant seeds into seed raising mix and place them in a green house. You can also use a mini greenhouse to raise seedlings which will capture humidity and slow the rate that the seeds will dry out.

After 8 weeks seedlings will be large enough to plant out. Make sure the chance of frost has passed and you have prepared the soil well.

I always like to purchase seedlings because it saves time. If you are organized then get your seeds growing half way through winter ready for spring planting.

What month can you plant petunias?

In many regions in the US, April is a good month for planting petunias. Just make sure the chance of frost has passed or keep the plants protected until this time. In Australia, plant petunias in September once the weather has warmed up. I planted mine half way through September and they have grown huge in that time.

Is April too early to plant petunias?

April is not to early to plant petunias in most areas. Always check the forecast to make sure that the chance of frost has passed. Once the weather has warmed, plant out seedlings. Make sure they are at least 3-4 inches tall and this can help to prevent pest attack.

What time of year do you plant petunias?

Petunias should be planted in spring, in a full sun position after the chance of frost has passed. Petunias are a spring and summer flowering plant. There are many varieties including those that grow into small bushes or grow into a large ground cover.

Can you sow petunias in May?

You can sow petunias in May however you will shorten the growth and flowering period. It is better to sow the petunias in early spring or even late winter. Protect them from cold weather and frost and they will establish their roots and stems before the weather heats up.

Petunias that are sown in May will generally end up smaller. Purchase seedlings and get them in the ground instead. You will save time and the plants will establish quicker.

Planting Petunias in Spring | Summary

Petunias will grow well if they are planted and established in spring. Sow seeds in winter and establish them in a greenhouse. Purchase seedlings in spring if you want to save the time and effort to establish seeds. Petunias are a low cost annual flowering plant that are great for plugging holes in flower beds or filling a hanging pot.

Happy growing.

For more on growing Petunias check out my previous articles here: