Watering petunia plants

Purple wave petunias in a hanging basket

Petunias are known to be hardy and versatile flowering plants. They grow easily and often grow in masses of color. They can be grown in many climates, but they do best if they’re given full sun exposure.

Many gardeners enjoy growing petunias as a hobby and to benefit from the beauty of the plant. If you are growing your own petunias, it’s important to keep in mind how to properly care for your plant.

In this article, we’ll be taking a look at how often to water your petunias. The answer will vary depending on a bunch of factors. We’ll analyze those factors and how they affect your petunia plant’s watering needs.

How often to water petunia plants

When it comes to how often to water petunia plants, the answer depends on a variety of factors. For example, is the petunia plant planted in a pot or in the ground? Is it in direct sunlight or does it only get a partial day of direct sunlight? What has the weather been like recently?

Generally speaking, the best way to determine how often to water your petunia plant is to check the top half-inch of soil for dampness. As a rule of thumb, if it’s dried out, give the petunia plant some water. If it’s still damp or moist in the top half-inch, then no need to water the petunia plant.

Watering petunias seedlings

When it comes to how often to water petunias seedlings, you want to make sure you give your young petunia plant the water it needs for its early growth.

Sometimes petunia plant seedlings are grown in bunches. These may soak up moisture faster, so keep tabs on the dampness of the soil for these seedlings.

It’s best to water them lightly more frequently than watering them a lot less frequently. Seedlings are more susceptible to “drowning” when they are overwatered. Too much water at once can also cause the plant to uproot itself, as soil washes away easier when the plant doesn’t have a solid root structure in place.

Plan on watering your petunias seedlings every few days, or even daily. Keep an eye on the surface level dryness of the soil, and give the seedlings a sprinkle if it doesn’t look moist.

Petunia seedlings are faster to show it if they don’t have enough water, so if the plant is wilting and the soil is dry, not enough water is probably the problem.

Watering an established petunia plant

Established petunia plants should be watered when the top half-inch of soil is dry. Below are specific growing scenarios and information on how often to water the petunia plant for each.

When to water petunias that is planted outside

Petunias planted outside is often healthier, as there’s more chance of direct sunlight, and airflow generally helps to protect it against disease.

Plan on watering your established petunia plant a few times a week when it’s planted outside. If you’re not sure whether it needs to be watered, you can check if the surface level soil is moist, or if the petunia plant is wilting.

When to water petunias that is planted inside

Petunia plants that are planted inside may not need as much water, as direct sunlight is normally not available. Be extra careful that you aren’t overwatering the petunia plant inside.

If the petunia plant is wilting, that could be a sign that it is under or over-watered. Keep track of how moist the soil is to know the difference before watering the petunia plant more.

When to water petunia planted in the landscape

Petunias that are planted in the landscape are able to pull up some moisture from the ground, so they won’t need to be watered as much as petunia plants are grown in a container.

When to water petunia planted in containers

As mentioned previously, petunias that are planted in a container will need to be watered more frequently since they don’t have natural water in the ground as a source of hydration.

Things to consider

There are numerous factors to consider when determining how often to water your petunia plant. Factors like weather, sunlight, the season of the year, and spacing all play a rule.


Spring weather is generally rainier in some areas, so you may not need to water your petunia plant as much. Be careful that you don’t overwater your petunia plant in a season with a lot of rain.

Sunlight exposure

Most petunia plant varieties grow great in full sunlight, but in the heat of the summer, you’ll need to keep these plants watered well. 

Petunia plants that are grown in full sun will dry out fast, especially if they are getting direct sunlight during the noon of the day.

Keeping the petunia plant well watered in these seasons ensures that they’ll be able to produce healthy new shoots of fresh petunias in the future.


Depending on the season, you may not need to water your petunia plant as much. In the fall, when the petunia plant is more established and the cooler weather sets in, you may only need to water the petunia plant once a week.


Petunia plants that are planted close together will compete for the same water, and as a result, you’ll need to water them more.

Tips for watering your petunia plant

Here are some tips for watering your petunia plants.

Your petunia plant may wilt with too much water or too little

Keep in mind that a petunia plant that is wilting does not necessarily always need water. Sometimes petunia plants wilt when they have too much water.

Always check the soil dryness to determine if you should give the petunia plant some water.

It may not be a watering problem, but a fertilizing problem

If the plant is wilting or looking yellow, it may not be your watering that is the problem. You may want to check the fertilizer level of the soil it’s planted in to see if that’s the problem.

Make sure your pot has adequate draining

If you are planting your petunias in a pot, it’s very important that the pot has proper drainage. petunias are susceptible to root rot if water does not drain through the soil, so well-drained soil is essential.


If the petunia plant needs watering a lot, you may want to re-pot the plant so that it has more soil to spread its roots in.

Recap: watering your petunia plant recap

In conclusion, there are many factors that will affect how often you’ll need to water your petunia plant. The best and most simple thing to do is check the moisture level in the top half-inch of soil to determine if it needs some water.