How to Water Petunias Properly

Last Updated on August 13, 2022 by Stephanie

In general you should water your petunias at least once a week, with a good irrigation to ensure healthy roots. Petunias like the soil to be evenly moist, but well-drained as wet soil can cause root decay. Make sure the soils top inch is only slightly damp before giving the petunias another large amount of water.

Heres a quick guideline on how to water your petunias in the garden, pots hanging baskets, and during hot weather. ….

Read on to learn how to water your petunias to ensure the proper level of moisture to allow for blooming and also how to set an appropriate schedule of watering for petunias based on the climate and conditions in your area…

How to Water Petunias

The most effective method to water petsunias is by giving them a really well-drained soak in the morning, and then keep them watered for 7 days before you water again. Petunias are drought-resistant and require a well-drained soil that is moist and are not tolerant of excessive watering or boggy conditions.

The first time you water your petunias in the morning fills the plants with moisture prior to the summer heat is upon us.

Petunias like lower humidity, therefore watering in the morning gives the chance for any water that falls on the leaves or in the vicinity of the petunias to evaporate when watering later in late in the day (when temperatures are lower and less water evaporates) could lead to conditions that can cause powdery mildew as well as other fungal illnesses.

Always give your petunias an extremely generous soak every week, rather than a gentle watering every day or once.

The constant watering helps the roots to grow and establish in the soil and the roots are able to draw up water when they need it.

The watering that is too light only moistens the soils surface which causes the roots to become shallow close to the surface in order to get the water that is available.

The shallow roots arent capable of absorbing the water that the petunias require in periods of drought, or the nutrients necessary for healthy growth and flowering.


How Often to Water Petunias (in Pots and Containers)

Petunias can be indigenous to South America where they thrive in warm, open regions with low humidity, and in soil that is well-drained.

Because of the South American origins, petunias are extremely drought-resistant and thats why theyre very popular to grow in containers, pots and hanging baskets.

Petunias planted in pots that have drainage that is good should be watered every week, with a good soak. The proper watering helps the roots of petunias grow and get access to the moisture within the soil, so they are able to withstand drought. If you water more frequently than every week could result in root rot since petunias cant endure soil that is boggy.

This recommendation is based in reference to the fact that the petunias should be planted in a pot that is large enough and, most importantly, that the pot isnt too deep.

Petunias, which are smaller plants, are actually quite deep-rooted which allows them to access more soil moisture as a way of coping with drought.

If the pot isnt deep enough, the roots of the petunias are unable to establish and get the water they need, which could cause them to die due to drought stress.

In the midst of constant heat and scorching sun, you might have increase the frequency of watering to two or three times every week.

If youre not sure the need to water your petunias, check the top inch of soil using your fingers. If you feel that there is the presence of moisture, you should put off the watering. If your soil is feeling like its dry, this is the ideal moment to water it with a good soak.

Petunia leaves can turn brown because of overwatering, and also underwatering as a method of conserving water in hot temperatures It is always recommended to touch the soil to determine if your petunias require watering. the signs of wilt may be an indication of root rot caused by the soil being boggy.

(Read my article on on how you can bring back dying petunias).

Petunias are also dependent on compost as pot soil because it can hold water, but also possess the well-draining structure that roots require to grow and get access to nutrients and moisture.

The composting process of planting petunias along with watering them once a week will help maintain the ideal moisture balance to your petsunias.

Pots and containers that have a good bath, so that the excess water drips off the bottom of the container. This will ensure that the water has soaked into the soil to ensure that its evenly moist and gets to the roots of the petunias.

It is recommended to place your petunia plants or containers onto pot foot so that they lift above the floor, to ensure that water can flow freely out of inside the container, as petsunias need moist soil, but dont like soil that is damp because this can cause roots to rot.

How Often to Water Petunias in Garden Soil

Typically, watering your petunias at least once a week in the garden soil will ensure an adequate level of moisture that will allow for the flowering process, but also to prevent root rot. Alter the frequency of watering petunias in case the soil dry quickly. Always make sure to soak them in water to encourage healthy roots.

How often you need to keep your garden petunias hydrated is dependent on other factors like the climate, drainage, and airflow conditions.

I suggest amending your garden soil by adding lots of compost to the area of planting prior to plant petunias in your garden.

Compost holds the water needed for the growth of petunias and also allows for adequate drainage to avoid root rot.

It is possible to increase the frequency with which you water your petunias when there is a lot of air movement, since it could suck up water from the leaves, and when there is warmer, dry conditions.

As recommended, the best method to determine the ideal time to water your petunias is to keep an eye on the soil and observe when the top inch of soil begins to feel dry. At that moment, you should ensure that your petunias are properly watered.

The majority of petunias grown in soil need less watering than hanging or potted petunias, and will benefit from rain.

But, a careful monitoring of soil moisture can allow you to determine the ideal timing for watering according to your climate and the conditions.

This watering cycle supports healthy growth. Your petunias will be displaying plenty of blooms, especially when they are in full sunlight.

How Often to Water Petunias in Hanging Baskets

Petunias that are in hanging baskets should be watered every week at least with a good soak. Hanging baskets offer exceptional drainage and a higher air flow, which both favor petunias. However, this also means that petunias may require watering frequently, as often as every two or three days during a hot period to prevent them from wilting.

How often you should water your plants in hanging baskets is largely dependent on the dimensions of the hanging container and the amount of moisture that the potting medium holds as well as the weather and the airflow.

There are a myriad of factors that influence the frequency of watering the hanging baskets of petunias, it is recommended to always feel the soil up to one inch of deep.

Petunias flourish when well-watered and are in full sunshine The soil is allowed to dry until it will be a little damp before replenishing the water.

This is similar to the normal cycle of watering that they encounter in their home country of South America and maintains the equilibrium of moisture which allows the roots of the petunias to absorb the water they require without having soil that is too moist and causing root decay.

If your basket is small or is stuffed with other plants, then you need to water the petunias more frequently.

Baskets that are shallow have less capacity for soil, and consequently less moisture, which could cause the petunias to die rapidly in hot temperatures.

When the basket is overcrowded, then the plants roots are competing for water, which increases the demand for water.

If you are able to feel the soil to determine the time when it begins to feel dry, you will be able to determine the right timing for watering your hanging basket based on your local climate to guarantee an optimal level of moisture that keeps the petunias in good health and to display flowers.

Key Takeaways:

  • Petunias are watered as often as needed to ensure that the soil remains moist, but not boggy. Petunias like evenly moist but well-draining soil. Typically, watering every seven days is the ideal amount of moisture to petunias. When the soil becomes not moist enough, this can lead to fungal and root rot.
  • Pots of water petunias should be watered every week at least by giving them a thorough soak, to ensure that water drips out of the bottom of the container. Re-water petunias when the top inch of soil begins to dry, and then give it a an extensive watering to encourage healthy root development.
  • Petunias that are water-loving in hanging baskets frequently as needed to ensure that the soil remains damp however not getting boggy. The soil dries out in hanging baskets faster and this increases the demand of petunias for water. Usually, you should water them once every two or three days to make sure that the petunias are hydrated enough.
  • Petunias should be watered in the garden every week, with a regular watering routine to grow roots. Petunias are remarkably resistant to drought, but they do not like soils that are boggy So make sure that the top inch of soil is dry before giving the petunias another watering with a good soak.


Went from an inexperienced gardener to a half-decent one over 10+ years. I cover anything from general indoor plant guides and lawn care, to succulents and flowers. Super happy to share my tips and tricks with you :)