How Much Water Do Petunias Need? [Watering Guide]

How Much Water Do Petunias Need

I have an extra space in my garden and I have been thinking of planting flowers. The flower which came into my mind is Petunias. I was not sure if they could grow well since a section of my garden is too dry and I didn’t have an idea the amount of water needed to produce beautiful flowers.

I did some research and came up with the following findings.

So, how much water do petunias need?

Petunias will need to be watered twice a day during hot and dry weather. Bedded petunias should be deep watered once a week especially when the topsoil about 5-6 inches dries up. Overwatering petunias will lead to root and shoot rot. Potted petunias should be watered slowly and at the base avoiding the flowers and leaves.

As water has lots of advantages, frequent and less watering can be too dangerous for the plant. Watering the plants lightly might end up making the plant produce shallow roots. This is not good since the plant will be blocked from getting enough nutrients and moisture.

On top of that, petunia has important watering needs, starting from the seedlings, garden beds, containers, and mulching. We will analyze the needs together with the corresponding importance.

 First of all, let’s kick off with the Petunia Seedling watering needs

Petunia Seedling Watering Needs

To have healthy and great petunias, start planting the seedlings indoors. What you need is a pot full of moist soil then cover it using a transparent plastic bag to retain moisture. When there is sprouting, keep on watering the seedlings. One thing you have to remember is too much moisture can cause fungal problems.

Garden Bed Watering Needs

Before planting them in garden beds, remember that petunias don’t tolerate soggy soils. Instead, plant them in evenly moist soil then keep on minimizing watering up to once in every seven to ten days.

Container Petunia Watering Needs

Planting petunias in containers is a good idea but it has vast drawbacks. As it saves on space, a limited amount of soil requires frequent watering to provide the flowers with water. For better results, check the level of water daily by either dipping your fingers or inserting measuring equipment like a water meter.

How Many Varieties of Petunias are there?

Petunias are among the most wonderful flowers to grow in your garden. The flowers are bright, lovely and available in a range of colors and sizes. The good thing is that they bloom from spring to frost and scent the air with lovely fragrance. There are several petunias which fall into different categories.

Keep on reading to find out.

Wave Petunias

These are among the varieties of petunias which scatter up to 2 to 4 feet. Also known as spreading petunias. They can grow well on cover grounds as they can drought and intense heat. Some of these petunias include: Shock wave, Avalanche and Easy wave.

Grandiflora Petunias

These are the oldest types of petunias which spindle in summer. They measure up to 12 cent and have large flowers. They include Ultra, daddy, Super magic, storm, Dream and Auper cascade.

Multiflora Petunias

They are best known for being smaller in size and blooming in windy conditions. Their bloom goes for long during rainy seasons. They include celebrity, mirage, carpet, horizon and primetime.

Petunias Growth Requirements

Petunias are among the easiest flowers to plant in your garden and containers. Here are important growth requirements that you need to follow.

Light Requirements

Light is one of the essential requirements to enhance growth of petunias. Petunias will bloom in bright indirect light but they will do better in a place where there is maximum light. Plant them in a place with no sun and they will become spindly as they cannot bloom in shade. Furthermore, they need sunlight for about 5 to hours daily.

Water Requirements

Another requirement to enhance the growth of petunias is water. As much as they require maximum light, Petunias also do well in well-drained soils. Constant watering will help them continue blooming or else they might perish.

Planting petunias in containers and beddings require a lot of care. If you are planting in containers during sunny seasons, water them at least twice a day. For bedded plants, water them at least once a week and ensure that it’s deep watering to produce long and healthy roots.

On the other hand, watering lightly and frequently is not good for petunias as they will grow weak and have shallow roots hence block them from getting enough nutrients.


Petunias thrive well in soils that have adequate fertilizer. They also like soils that are neutral to slightly acid. The most preferred soil is light sandy soil mixed with organic matter. The most important thing is that the soil drains well. If you are planting them in the garden, ensure that you balance the fertilizer as follows:

  • Balance 12-12-12 or 8-8-8 in the soil.
  • Fertilize spreading petunias weekly
  • Use liquid fertilizer every three weeks from early to mid-July.

For spreading petunias, leave sprinklers to soak the soil when you need to water them. What’s more, run a soil test in the garden if you are supposed to use a specific type of fertilizer to see if they fit.


As mentioned earlier, petunias thrive best in well-drained soils. Since they are quite versatile, they grow well in different types of soils as long as the soils drain well. Aside from that, they also grow well in healthy soils since they have undemanding water requirements. To enhance blooming, you can plant them in compost.

The following are useful steps to follow when in case you are using compost.

  • Spread the compost to about 2 to 3 inches thick.
  • Mix it well in the soil to a depth of 8 to 10 inches to increase soils strength of holding nutrients and drainage.

How to Propagate Petunias

To propagate petunias, follow the following steps:

  • Cut the leaf joint and remove them from the stem and flower.
  • Put them in a container full of water.
  • Make holes and insert cuttings in the each hole.
  • Put soil around the stem then put the container in a place full of light.
  • Water the new plants twice a day and transplant them in a flower them if you want to.

Ways of Harvesting Petunias

Petunias are great plants to grow even if they have few requirements that might be quite challenging to follow. To harvest petunias, follow the following steps:

  • The first step is to check whether the seed pod has developed by conducting a regular check on the flower.
  • Cut the seedpod when the calyx turns from green to brown. Leave it to crack to ensure that the seeds have matured.
  • Spread the seed pods on a tray or flat surface then cover with paper towels.
  • Store them in a cool dry area for about a week.
  • Squeeze the seed pods as they fall in a bowl.
  • Before collecting debris and husks, pour them in an envelope then put them in a plastic food container.
  • Make your own desiccant by wrapping a teaspoonful of dry milk.
  • Store the packet in a cool dry place until the next season arrives.

Insect and Disease Problems

Petunias are beautiful flowers that are easy to grow. But that does not mean that they are perfect. Just like any other plant, they are prone to pests and diseases. Such pests and diseases include:

  • Aphids
  • Mites
  • Caterpillars
  • Slugs
  • Leaf miners
  • Botrytis Blight
  • Stunt
  • Phytophthora Crown rot

With proper gardening care, this pests and diseases can be reduced.

Frequently Asked Questions

  1. Do Petunias require much water?

Petunias thrive well in well-drained soils. An adequate amount of water will help them bloom. On the other hand too much water might not be good for them as they will grow weak.

  • When do they start blooming?

Petunias are glamorous plants that bloom when exposed to proper care. These plants start blooming from late spring to mid fall.

  • What should I do during winter?

Winter is accompanied with too much cold and that is why some people mistake for s good time to plant Petunias. These plants will fail grow in freeze as they are annuals. They won’t bloom in winter but will do better during warm climates.

  • Why are they known as special plants?

Petunias are indeed special due to their ability of producing much flowers. If you plant them in a suitable location that receives all nutrients, they will not fail to bloom. Additionally, if you plant them in beddings or containers, be prepared to provide adequate water but not in excessive amounts as they will fail to get all the nutrients and die.

  • Do they need frequent care?

Petunias don’t require extra care as they do well in almost all conditions apart from excess water for those in containers.

Bottom Line

Almost everyone loves Petunias. They are gorgeous flowers with pleasant smell and produce a lot of flowers. These plants don’t need too much requirements for them to thrive well. In terms of water, they need well-drained soils and adequate watering. However, too much or frequent watering might make those in the garden weak.

I tried planting petunias and they did not disappoint me. These flowers will make your garden beautiful and colorful. If you desire to plant them, follow the guidelines outlined above for them to thrive well.


I love nature and fresh food from the garden. That's why I started this gardening journey and decided to share my experience with the world. So far it has been an amazing journey. I hope you will enjoy reading my gardening journal and never be the same again!

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