Rescuing Overwatered Petunias (Signs and Reason Behind Overwatering)

by Becky Decker and Anita Shan · July 4, 2024

I was so happy to see my petunia flowers blooming that I overwatered them in excitement, causing the flowers to start falling within a few days. Recognizing my mistake and knowing how to solve the problem, I quickly adjusted the watering schedule, and soon my petunia plants began thriving happily again.

However, I realized that many may not have any clue about the risks of overwatering and how to rescue their plants. That’s why I’ve shared my experience of growing petunias here—to help you learn how to properly water them and, if you encounter the problem of overwatering, how to save them.

If you have any doubts regarding petunias or any other plants, feel free to comment below.

Quick takeaways:

The overwatered petunias start to die when they are fixed quickly.
some easy ways will help you to check whether they are overwatered or not such as having chlorosis, leaves drooping, flowers getting wilted, formation of mold on the substrate or soil, and many more.

Signs of Overwatered Petunias:

There are some signs you will get to see when the petunias are overwatering or, as I will say, the plant is giving emergency signals, which I’ve explained below:

Chlorosis (Yellowing Leaves):

Chlorosis means leaves turning yellow.
The petunia used to get water by sucking from the soil, not oxygen and nutrients, but if they get over water, you will see their leaves turning brown and yellow.
Having chlorosis can be a symptom of many problems in plants, so it’s important to check all the symptoms related to overwatering.
It’s a good decision to notice that chlorosis is caused by overwatering because it will affect every leaf and flower of the plant.
The other cause of chlorosis can be a nutrient deficiency, in which some of the leaves will be green and others will be yellow.
Make sure to confirm the real cause behind yellowing leaves before drawing the conclusion that it is because of overwatering.

Rescuing Overwatered Petunias (Signs and Reason Behind Overwatering)

Brown and Wet Patches on Leaves:

Having brown and wet patches on leaves is due to very high humidity.
The petunia leaves will start to have brown patches when you continue watering the plant in the fall months and other months with high humidity.
The signs of brown and wet patches indicate the plant is getting much more water than it needs through its roots, and due to high humidity, water is not disposable through transpiration, resulting in cell bursting.
When you find brown patches on the petunia leaves, I suggest checking them with your thumb, they will have a wet or dead feeling, which is the main reason for not watering the plant regularly during fall months as you do in other months.

Root Rot:

Well, root rot is the most common way to find out if the petunias are getting more than enough water in their substrate.
However, I wish this symptom would be the least you see because it can kill the plant.
Root rot is a fungal attack that happens when there are damp substrates.
During overwatering, the plant gets attacked by fungi on the roots, and slowly every root will start to die.
The petunias’ leaves and stems will start to weaken and fall due to root rot.
If you detect root rot early enough, then there is enough time to save the plants.

Drooping Leaves:

If the plant gets overwatered, it will bend or droop its leaves. In short, the leaves will not be firm or erect.
The drooping leaves will be very weak to feel and will soon start to wilt or die.
The drooping of leaves is also a sign of plant nutrient deficiency.
Drooping is caused when the petunias collect more water than they need, after which the cell walls of their petioles will start to burst, and when more cell walls burst, the leaves will no longer feel firm or erect.
If the leaves start to wilt, the nutrients will no longer go to the leaves through the petioles.

Wilting or Falling Flowers:

Petunias are famous for their stunning flowers, so when you see falling flowers, it will upset you.
If the plant gets overwatered, the flower will either wilt before falling or fall immediately when the plant is stressed.
The petunias need a lot of nutrients to produce and maintain their beautiful flowers.
Although falling off each flower or getting wilted at once is not possible, there is some time to find the reason behind it after noticing wilting or falling flowers.

Having Mold or Fungus Gnats in Substrate:

The top sign of overwatering petunias is seeing mold or fungus gnats in the plant’s substrate.
In fact, this method can be used on every plant.
If the soil gets too saturated with water, the roots of the plant will start to die and will attract decomposing fungi.
If you find a large number of fungi on the substrate, then it’s time to produce mold on the surface of the substrate.
These molds are eaten by insects such as fungus gnats, so unfortunately, these insects will be attracted to the substrate. All these indicate that the plant is being overwatered.

Weak or Dying Plant:

This is the final sign that the plant is overwatered when Petunias starts to die.
However, they don’t usually die without showing any signs, so it’s your job to identify what’s going wrong that is making the plant die.
The possibility of saving the petunias is only possible when they are still alive.
The petunias that are going to die will have leaves falling or wilting, flowers dropping, and roots dying.

How to Fix Overwatered Petunias:

When you find the petunias suffering from overwatering, it’s time to take quick action, and here are the steps you need to follow that save your overwatered petunias:

Step 1: Tip Petunia from the Pot:

Allow the excess water to drain so that air can enter the soil.
In order to speed up the process of draining, make the root ball stand on a sheet of paper and leave it there to dry out.
The whole process will take two or three days to complete, which makes sure the plant is not kept in direct contact with the sun during the whole process of drying the roots.
The reason behind not providing them with direct sunlight is that the root and stem will both be fragile and if they get too much light, they will transpire more rapidly.
When the roots of the plant dry out, the root ball will absorb some air, which will turn it from soggy to slightly moist.
Many promote the idea of squeezing the root ball, which helps to speed up the drying process, but I will not suggest it because there is a risk of damaging the root by pressing them

Step 2: Trim off Infected Roots:

After drying the roots, it’s time to repot the petunia, which should only be done when the root ball is not rotten.
Root rot happens because of overwatering. The healthy roots are firm and white, and the roots that are rotten will die and turn an orange-brown color.
The roots, when infected, will lose texture and become soggy and these brown pieces are not fit for purpose.
When you notice brown roots, simply snip them away using a pair of scissors unless the roots are clean and healthy looking becoming root material again.
Ensure to clean the scissors after cutting the damaged roots because it will transfer disease to other plants like aphid pests.

Step 3: Ensure Drainage Capacity of The Pot:

The next step is to check that the pot of petunia has sufficient drainage holes.
The pot’s lack of drainage capacity will pose a problem for the plant.
Without drainage holes, the water will have no means of escape, and after some time, the root ball will become soggy and Petunia will suffer.
You need to have at least one hole in the bottom of the pot, which must be large enough that your finger gets into it.

Step 4: Repotting Petunia:

The next step is to add good quality potting soil because the petunias are not fussy in case of soil quality.
Never use any soil that is dropped off the root ball in a new container because here the soil is still damp, and secondly, they do carry pathogens that damage the plant, which is weakened.

The following are some points that you need to remember while repotting:

Repot the plant into a pot that is the same size, and keep the plant at the same depth as the one you planted before.
Make sure the top of the soil lies an inch below the lip of the pot so that the gap between the top of the soil and the top of the pot will get water without slopping everywhere.
You can keep the soil at the bottom of the container and keep the plant in it to check if it’s at the right depth. In case it’s not, add or remove soil accordingly.
After having the petunias at the perfect depth, fill back the soil around the root ball using new potting soil, and then push the soil down using your fingertips.
The main motive for pushing soil is to squeeze out air pockets, but this doesn’t mean making the soil too compact, which will damage the roots by backfilling.
Now it’s time to place the pot in a plant saucer while leaving the plant in a low-light place for a few days or until you see any sign of the plant reviving.
After completing the repotting process, don’t water them in a hurry because there is the possibility of moisture lingering around the root ball due to its past experience, and the potting soil that you use is already slightly damp.
Actually, the petunias will need water for at least three days. When the plant starts to look healthy again, then it’s time to move the plant back into a position where it gets more direct sun and water the plant according to the method explained below.

Note:

Yes, healthy petunia requires plenty of direct sunlight even when it’s grown as an indoor plant, but it should be reintroduced to the sun slowly because moving them into full sun too quickly will make them suffer and wilt due to the root system not being in peak conditions.

You can place the plant in the sun for an hour on the first day after repotting the plant.

After a week, the plant will be back to its old self and will survive several hours of direct sun each day, but if the plant is not getting enough light, it will either produce small flowers or no flowers at all.

Ways to Water a Petunia:

The petunia plant that is grown in the same garden setting as petunias is more tolerant of dry spells but you may water them as little as once per week.

In the case of growing the petunias in a container, you should pay more attention to the watering technique.

Watering Rules:

When you water the water from the top of the soil but make sure not to water the flowers or leaves.
If the water sits on the upper parts of the plant it will result in the production of fungal diseases to which they are prone.
Target watering at the base of the plant because watering reduces disease forming.

Watering Frequency:

The perfect way to water the petunias is after feeling the surface of the soil using the fingers and when it feels dry it’s high time to water the plant.
Some people water petunias because they think that it’s time to water them without noticing any other indications.
The moisture level of the soil indicates how often the plant needs water rather than believing in its guts.

Factors Influencing Watering Frequency:

There is a reason behind checking the soil every day because there are many factors that indicate how much the plant requires water.
The larger plants will require more moisture and will require more water than the small ones.
In cases of humidity, soil retains water longer than when the surrounding air is dry.
When the soil gets old, its ability to hold onto moisture deteriorates, and it will drain away water faster.
The amount of sun falling on the plant also changes the watering capacity by changing the speed of draining.
You can check watering needs using a finger to check the soil surface, which will guide more accurately how much they need water.
Some factors combine to decide how often to water petunia plants.

Water Quality:

The petunia plant should be watered with rainwater, filtered water, or distilled water.
In the case of regular tap water, make it pass through a chemical process to remove contaminants.
Using tap water for a prolonged period where the chemicals end up building up soil in the form of salt, which becomes detrimental to plant health.

Common Mistakes and Solutions:

Well-watering requirements make it easy to take the wrong step unless you don’t understand the right process. After finding the right process, you will see how easy it was to get it right, and you will wonder why you didn’t think before, as it will save your petunias from overwatering. These are some of the most common mistakes with solutions you can acquire.

Common Mistakes	How to Avoid Them
Inconsistent watering	The inconsistency of watering petunias often occurs when, before watering petunias, you don’t check the moisture levels daily. Make a habit of checking and feeling the soil at least once a day. It’s just a matter of seconds and is a cheap and reliable method that will result in maintaining soil that remains moist but not wet.
Too much watering	Avoid watering the plant when the surface of the potting soil feels completely dry. The house plant dies mostly due to its owner’s mistakes of overwatering and
Wet soil	The soil getting wet occurs, in case of not have enough drainage or if you water the plant when the soil is not completely dry. Make sure to check the drainage holes and ensure that the soil is dry between each watering. Avoid using potting mixes that are too rich in water-retentive materials, such as sphagnum moss.
Water on leaves	Never wet the leaves of petunias while watering them; that will lead to having fungal problems. If they suffer from a fungal problem, you will see a gray or white powder-like mildew on the surface of the leaves. Make sure to water at the soil level only where the top of the plant stays dry.
Water during the heat of the day	This mistake occurs when it is hot and the petunia needs access to moisture. You should water petunias when the water you supply evaporates or the situation when the plant is competing with the atmosphere. In the case of watering the petunias in the morning, they will have time to absorb watering and use it efficiently resulting in reducing stress and increasing the growth of the plant.
Incorrect cultivar	Petunia comes in many different types, and many of them are specifically bred for outdoor cultivation. In case when you are choosing an indoor plant, you should choose the compact varieties, which makes them easier to manage. There are cultivars that requires less water in which the leaves and stems don’t get to spread as widely due to which they will not get water in the upper regions of the plant.

Other Growth Requirements:

Overwatering petunias leads to various problems, so there are many other requirements of petunias that you need to pay close attention in order to grow the plant easily. The following are some of the petunia growth requirements that you need to take care of:

Substrate Requirements:

The petunia loves the soil or substrate that is sandy and light, which is well draining.
The pH level of the soil for petunias is 6.5.
Talking about the pot or container, don’t use a container that is three or more inches larger than the root system.
Make sure to perforate the containers or hanging baskets for drainage holes.

Temperature Requirements:

When it’s the day house ensure that the petunias are placed in a room with 60-75 degrees Fahrenheit.
During night they need to have 55 to 65 degrees Fahrenheit.
The people who live in USDA hardiness zones 9 to 11 the perfect for growing petunia where there is no need to check temperature constantly but living in other zones means first checking whether the variety is suitable to grow or not.

Humidity Requirements:

Petunias love to enjoy high humidity as long as they are not having issues with overwatering.
The room or environment around the petunias should be 55-80 percent in which they will not suffer any humidity-related problems.
If you find the humidity level around the plant is low consider buying a humidifier.
Always make sure not to keep the plant in a place having strong wind.

Nutrient Requirements:

Make sure to feed petunias using a balanced fertilizer such as 8-8-8, 10-10-10, or 12-12-12.
The perfect time for fertilizing them is during the active growing season from spring to autumn where you can feed them weekling.
Always use soil that is nutrient rich as it helps in producing a lot of leaves and flowers.
Just check the fertilizer 46-0-0 and 0-0-60 Fertilize is considered very popular and helpful.

Petunia Leaf and Flower Care:

The perfect way to take care of the leaves and flowers of petunias is by providing them with all the required conditions.
If the plant gets the best environment it will not face any issues while growing and will result in having the best appearance.
Trying misting the leaves with water droplets that too occasionally

Final Words:

The petunias when grown indoors will give an attractive visual and to have a unique houseplant. It’s easy to care but overwatered petunias get a big issue. Watering is a technique that you can master in a short time just follow all the above rules of watering. Once you learn the amount and way to water petunias by following the above method then you will get the result of growing a very happy and vigorous plant.