How To Grow Petunia Flowers – A Simple Step-By-Step Guide

After those few articles about flowers in the past few weeks, I have decided to switch to vegetables and fruits, but I have forgotten one important plant. Today, I’m rectifying this, since I will show you how to grow petunia in your backyard.

A lot of people don’t know what to plant in their garden, so this guide will show you that petunias are great when introduced. Also, I took more of a beginner-friendly approach, which means that I have started from the basics, and carried on toward more complicated aspects of growth.


How To Grow Petunia Flowers – A Simple Step-By-Step Guide

Common Knowledge About Petunias


Although you have seen petunias somewhere at one point, there are some things which I need to mention. This will improve your overall image of this flower. So, let’s get to it, shall we?

  • check
    Petunias originate from South America
  • check
    Its name comes from French petun which means “tobacco”
  • check
    Most varieties which are grown in gardens are hybrids
  • check
    There are two large groups of petunias; grandiflora and multiflora
  • check
    Can tolerate harsh and hot weather
  • check
    pH of the soil should be between 5.5 and 6.3
  • check
    Too much water can kill the plant

As we can see, the conditions for growing petunia flowers are common, so we can freely conclude that this flower won’t give you much trouble. However, this doesn’t mean that you can just leave them to grow on their own. Proper care is vital in gardening overall, and this is not an exception.

Preparing The Soil

Preparing The Soil

When it comes to soil preparation, there are general rules which need to be followed. It’s nothing too scary, so don’t worry, I believe that you will do just fine.

First of all, I need to clarify those two groups which I have mentioned in the introduction. They are grown in the same way, but the location is different for them. Grandiflora are those varieties which have large flowers (thus the name) and are suitable for container or basket growing.

Multiflora is recognized by their small but high in number of flowers. These cultivars are more resistant to wet weather and more rain, so those are better grown in gardens, where there are high chances of large precipitation.

Now, when it soil preparation is in order, mind that location matters most than everything. So, find a piece of land where the sun covers the ground for at least six hours per day. Five hours is an absolute minimum, and shade can be tolerated, but the flowers will be smaller.

Organic matter is vital for healthy growth, so as soon as the soil becomes workable, add two or three inches of compost or old manure. Generally, you don’t need to go for high nutrient value, but rather for improving drainage. This is best done on soil with high clay percentage since such ground is not well-suited for petunias.

Planting Petunias

Planting Petunias

In case that you wish to start the seeds indoors, you can do this by beginning with the procedure some 12 weeks before the last frost. Just spread the seeds thinly in the trellis, water them generously and place somewhere lit, but with indirect light.

Once three leaves appear, you can consider to move them to the garden. Note that by this time the temperature has to be stable and at least 60°F. This is a minimum, so aim for even higher. Planting procedure is pretty straightforward. Dig a hole slightly larger than the root ball and place it inside.

When it comes to container planting, the procedure is the same, only that you can start the seeds in a pot, and leave them as they progress.

Right after planting, you should add water, to help the plants overcoming shock after moving. It will also help the soil to settle better. As for spacing, you should leave at least one foot of space between each plant. This will provide enough sunlight for all of them, as well as proper airflow to prevent any disease.

Care And Pests


Petunias aren’t demanding plants. Quite the contrary, we can say that they are easy to maintain and grow. There are but a few things which need to be looked after, but nothing drastic.

As I said, petunias thrive in dry and sunny areas. Therefore, don’t overdo with water. It needs this liquid to survive, no argue about that, but don’t keep the soil moist. Instead, apply water once a week, but in more substantial quantities.

If you are uncertain about whether to add water or not, you can skip it once. It won't do any harm at all. And, if you wish to improve blossoming, remove dead and wilted flowers as soon as you see them. This way the plant will be able to “reroute” its nutrients better.

Fertilizer is important but not vital for growing petunias. It will improve the looks and size of the flowers, but the plant can grow without it. Double-flowered varieties will need fertilizing once in every two weeks. There are several good recipes here, so you can choose whichever suits you. Equal one such as 10-10-10 is the best.

Pests which can harm your precious petunias are ordinary bunch made of aphids, leaf miners, and caterpillars. The best way to deal with them is to introduce beneficial predators. Namely, Diglyphus isaea is a wasp which will eliminate miners, while ladybugs are great for dealing with aphids.

As for diseases, there are several kinds of molds and virus diseases. Gray mold and bacterial soft rot are best prevented. To do so, when watering, care that you don’t wet the foliage. Add water directly to the soil because of this.


So, we reached the end of this article. As you can see, it is not a big deal, so I think that you know how to grow petunia flowers and that you will introduce them to your garden. They will grant you access to one of the most beautiful flowers in existence.
If you have some thoughts, opinions or ideas, feel free to share them in the comment section below.

Leave a Comment