How Often Should You Water Petunias in Pots?

Petunias are a great addition to any garden but need special care. Whether you’re new to gardening or just love petunias, you may wonder how often you should water your plants. 

Your potted petunias should get about an inch (2.54 cm) of water every week. Watering once a week or every seven days is ideal for potted petunias because their pot will hold water and keep them moist throughout the week. However, if you live in a hotter or rainy climate, adjust accordingly. 

In this article, I’ll tell you everything you need to know about keeping your petunias healthy and happy — at least hydration-wise! 

Ideal Watering Routines for Petunias

Like any other plant, petunias need water to survive. As a general rule, petunias in pots need to be watered more than those growing directly in the ground. This is because petunias in pots cannot absorb water from the surrounding soil, so they don’t receive as much water as plants growing in the ground. 

However, you should also keep in mind that pots drain more poorly, leading to water logging.

When watering petunias in pots, use room temperature tap water or rainwater if possible, because cold tap water can shock the roots

Factors To Consider When Watering Petunias

How often you should water your petunias in pots depends on a few factors. The first is how much rainfall you receive and the climate and temperature of where you live.

Next, consider the soil you’ve chosen for your potting mix (if you’re using one). Some soils retain moisture better than others, so petunia growers must know which soil best suits their plants. 

Avoid anything with too much peat moss, as it can make plants more prone to waterlogging. Sandy soil tends to be best for petunias. Many gardens naturally have different types of soil, but since your petunias are potted, it’d be a great investment to get them the right type of soil rather than just pulling from your current flower beds. 

If it’s hotter where you live, you’ll need to water your petunias more. If it’s cooler, they might not dry out as fast. 

Regardless, an easy way to check is by sticking a finger or stick into your pot while avoiding the roots. If your finger or the stick comes up moist, your soil is perfect. If it comes up bone dry or muddy, you’ll need to make adjustments. Dryness indicates a lack of water, while muddiness indicates an excess. Mulching can help with the latter issue. 

Dangers of Overwatering Petunias

Watering too often can also be a problem, as it can cause water logging or flooding. This, in turn, can lead to root rot and cause the plant to stop growing altogether. 

Soil compaction is another danger of overwatering your plants. As you pour more water into the soil around your plant, it will become more compacted, creating less room for roots to grow and absorb nutrients. 

Over time, this could result in these roots being unable to reach further than they already have and dying off altogether — meaning that even if you stop watering them excessively now, they’ll still die.

Over watering will also cause your petunia to grow too fast, resulting in a tall plant that falls over when it gets too large.

Helpful Watering Strategies for Petunias

By now, you probably have a good idea of how often your petunias need to be watered.

Here are three helpful strategies to ensure you’re providing your petunias with the right amount of water:

Irrigation System

These allow you to control your plants’ water by setting timers and monitoring soil moisture levels in real-time. They’re especially great for gardens with many plants and only one person caring for them. There are several types of irrigation systems you can choose from, depending on your needs and how much money you want to spend. 

For the sake of brevity, however, I’ll only cover two of the most common types of irrigation systems.

Drip Irrigation

Drip irrigation is one of the most common types of irrigation systems. It uses small tubes that run along the ground, watering individual plants as they go. Because it doesn’t waste water by pouring it all over one plant at once, drip irrigation is very efficient — and it also ensures that no water goes to waste.

If you want more information about drip irrigation, you can read my other article: How Long Should You Water a Garden With Drip Irrigation?

Sprinkler Systems

Sprinkler systems are another great option if you’re looking for an easy way to get your plants watered without having to do much work yourself.

All you need to do is set up a sprinkler system in your garden, turn it on when necessary (usually at night), and then let it do its thing. 

Unless you have an extremely large garden, however, this method will probably not be enough on its own. You’ll probably want to supplement with some other form of irrigation as well.

Using a Moisture Meter

Moisture meters measure the relative humidity of the soil and tell you if it’s best to water at that moment or wait until later down the road when things might dry out more than usual due to weather conditions (e.g., heat waves). Moisture meters will often also tell you the pH, temperature, and sunlight your plants are getting. 

Instead of guessing how much water your plants have, you can test with a moisture meter to calibrate yourself. These are especially useful if you have multiple plants in the same garden. 

Self-Watering Pots

If you’re not sure what self-watering plant pots are, they’re exactly what they sound like — plants in pots that water themselves. They have a special base that holds water and allows the plant to drink from it as it needs. You can set up these pots to use a timer or be completely hands-off, depending on what works best for your lifestyle.

The reason someone would choose a self-watering pot over a regular pot is simple: It’s so much more convenient. You don’t have to worry about keeping track of water levels or having the right amount available (especially if you travel often). And because these pots come with their base system, there’s no need for extra equipment or accessories. Just pop it in the ground and go!

How Do I Know When My Petunias Need Water?

As I’ve explained, over-watering will cause root rot, leading to fungus and disease problems in your plants. On the other hand, you don’t want to give your petunias too little water either. So when should you water your petunias?

Your petunias need water if the soil is dry, they seem droopy or leggy, or if surrounding temperatures are too high. Usually, you should only need to water your petunias once every seven days. However, if you have noticed they may be dry or need water, you can change your routine. 

Petunias in pots need more frequent watering than those planted directly into the ground because they’re housed inside containers that hold less moisture than open ground does. 

So, keep an eye out for signs of wilting foliage as well as roots that start growing up through drainage holes at lower levels on pots’ outside walls. These signs are typically good indicators of dehydration.

On the other hand, improper drainage can lead to your plants having too much moisture or water. 

One way to help determine how often you should water your petunia pots is by sticking a finger into the soil. If the soil is dry, the petunias are droopy or leggy, or if you’ve noticed your petunias can’t get enough water, you should give them a little drink. If your potting mix feels moist but not soggy, you’re doing well.

As mentioned above, a moisture meter will be your best friend when determining how much water is in your plants. It’s worth the investment, and most are pretty affordable. 


When watering your petunias, you want to ensure they’re getting enough water to thrive. A good rule of thumb is to keep an eye on the soil and the plant itself and pay attention to whether or not it needs water. 

If you think your petunias need more water than usual, consider increasing their frequency until they are back on track with their normal routine. Double-check with a moisture meter, and you’re set!

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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