Garden petunia needs water regularly throughout the growing season. Beginning in spring, you should plan to water this plant about once per week. As the season presses on and grows warmer, you may need to increase your watering rate to about two to three times per week. Exceeding at this rate can be detrimental to your Garden petunia. With that said, you should also ensure that the soil in which your Garden petunia grows remains relatively moist but not wet, regardless of how often you must water to make that the case. Watering Garden petunia that lives in a pot is a bit different. Generally, you'll need to increase your watering frequency, as the soil in a pot can heat up and dry out a bit faster than ground soil. As such, you should plan to water a container-grown Garden petunia a few times per week in most cases, versus just once per week for an in-ground plant.

There are a few different ways you can go about determining how much water to give to your Garden petunia. Some gardeners choose to pick their water volume based on feeling the soil for moisture. That method suggests that you should water until you feel that the first six inches of soil have become moist. Alternatively, you can use a set measurement to determine how much to water your Garden petunia. Typically, you should give your Garden petunia about two gallons of water per week, depending on how hot it is and how quickly the soil becomes dry. However, following strict guidelines like that can lead to overwatering if your plant requires less than two gallons per week for whatever reason. When growing Garden petunia in a container, you will need to use a different method to determine how much water to supply. Typically, you should give enough water to moisten all of the layers of soil that have become dry. To test if that is the case, you can simply stick your finger in the soil to feel for moisture. You can also water the soil until you notice a slight trickle of excess water exiting the drainage holes of your pot.

To water Garden petunia, you can use a garden hose with a spray nozzle, a watering can, or just about any other common watering tool. Generally, Garden petunia is not too picky about how they receive their water, as they can live off of rainwater, tap water, or filtered water. Often, you should try not to water this plant from overhead, as doing so can damage the leaves and flowers and may lead to disease as well. At times, the best method for watering this plant is to set up a drip irrigation system. These systems work well for Garden petunia as they apply water evenly and directly to the soil. For one Garden petunia that grows in a container, you can use a similar watering approach while changing the tools you use. To water a container-grown Garden petunia, use a cup, watering can, or your tap to apply water directly to the soil.

It can be somewhat difficult to avoid overwatering your Garden petunia. On the one hand, these plants have relatively deep roots that require you to moisten the soil weekly. On the other hand, Garden petunia are plants that are incredibly susceptible to root rot. Along with root rot, your Garden petunia may also experience browning as a result of overwatering. Underwatering is far less likely for your Garden petunia as these plants can survive for a while in the absence of supplemental watering. However, if you go too long without giving this plant water, it will likely begin to wilt. You may also notice dry leaves.

The remedy for underwatering Garden petunia is somewhat obvious. When you notice that your plant lacks moisture, simply begin watering it on a more regular basis. The issue of overwatering can be a much more dire situation, especially if you fail to notice it early. When your Garden petunia is overwatered, it may contract diseases that lead to its decline and death. The best way to prevent this outcome is to choose a proper growing location, one that receives plenty of sunlight to help dry the soil and has good enough drainage to allow excess water to drain rather than pooling and causing waterlogged soils. If you overwater your Garden petunia that lives in a pot, you may need to consider changing it to a new pot. Your previous container may not have contained soil with good drainage or may not have had sufficient drainage holes. As you repot your overwatered Garden petunia, make sure to add loose soils and to use a pot that drains efficiently.

You can expect your Garden petunia’s water needs to increase as the season moves on. During spring, you should water about once per week. Then, as the summer heat arrives, you will likely need to give a bit more water to your Garden petunia, at times increasing to about three times per week. This is especially true of Garden petunia that grow in containers, as the soil in a container is far more likely to dry out faster than ground soil when the weather is warm. In autumn, while your Garden petunia is still in bloom, it may need a bit less water as the temperature has likely declined, and the sun is no longer as strong as it was in summer.

Garden petunia will move through several different growth stages throughout the year, some of which may require more water than others. For example, you will probably start your Garden petunia as a seed. While the seed germinates, you should plant to give more water than your Garden petunia will need later in life, watering often enough to maintain consistent soil moisture. After a few weeks, your Garden petunia will grow above the soil and may need slightly less water than at the seedling phase. Then, once this plant is mature, you can begin to use the regular watering frequency of about once per week. As flower development takes place, you may need to give slightly more water to aid the process.

There are several reasons why most Garden petunia grow outdoors rather than indoors. The first is that these plants typically grow to tall. The second reason is that Garden petunia needs more daily sunlight than most indoor growing locations can provide. If you are able to provide a suitable indoor growing location, you may find that you need to give your Garden petunia water a bit more often than you would in an outdoor growing location. Part of the reason for this is that indoor growing locations tend to be a lot drier than outdoor ones due to HVAC units. The other reason for this is that soil in containers can dry out relatively quickly as well compared to soil in the ground.

Garden petunia is a kind of annual plant so it doesn't need much pruning. You only need to cut off and clean the diseased, yellow or dropped leaves and stems during its growing period. This will help your Garden petunia to stay away from pathogens infection.

Expect to prune your Garden petunia every week if it’s growing well or every two weeks if it grows slowly.
It is always good to prune it on sunny days because if you prune it on rainy days, the rainwater will distain the cuts and cause the whole plant to be infected.

During the growth of the plant, yellowing, drying and spotted leaves are produced, and these spotted and discolored leaves need to be trimmed off. If the whole piece of leave is discolored or infected, you will need to cut it off completely. In other situations, you will only need to cut off the discolored or infected part on certain leaves.
Garden petunia above the ground will die and dry up in the winter, and the dead plants need to be cleaned up.

Because Garden petunia is an annual plant, the pruning should take place basically during the seasons that the plant grows rapidly. During the growth of the plant, yellowing, drying and spotted leaves are produced, and these spotted and discolored leaves need to be trimmed off.

1. Sterilize all the tools before pruning; unclean tools will pass pathogens to the plant through wounds;
2. Prune on sunny days because the new cuts will be infected by pathogens if they're distained by rain or water.
3. Throw all the waste leaves and stems into trashbins, they will easily rot and attract diseases and bugs

Garden petunia leaves are delicate, so take care not to score or bruise them. Unless the leaves are withered or heavily discolored, do not prune the leaves from the lowermost branches unless they’re damaged. They typically grow the largest, so they supply the plant with critical energy to keep it growing right. Please prevent the wounds from water after pruning until they are fully recovered. Remember always sterilize the tools before pruning. When the pruning is finished, please throw all the waste leaves and stems into the trashbins to avoid diseases and bugs.

While Garden petunia doesn’t require any changes in temperature to enter different growing phases, it is important to stay consistent. Wild temperature fluctuations can slow down its growth regardless of its current phase, so it's always better to keep them in a controlled environment. That optimal temperature range of 77°F and 90°F (25-32℃) is vital to maintain, especially staying above the lower limit. Going above 90°F isn’t ideal, but as tropical plant it won’t suffer too much. On the other hand, going below 77°F (25℃) (and especially 41°F/5℃) will begin to directly damage this heat-loving plant species.

Garden petunia does not need different temperatures for different growing seasons. The most important step in seasonal care is to keep the environment within the optimal temperature range. That's why it's always best to keep this plant indoors. That way, you can control the temperature no matter what the climate is like outside.

Light is also important for tropical species, with all of these plants preferring a partial side level of sun exposure. This means any light they receive needs to be dappled or filtered, with bright but indirect light being the best option when growing your plants indoors. Too much direct sunlight can negatively affect your plant’s leaves, reducing its growth potential.

Tip #1: Don’t Leave Your Plant Near Windows in Colder Months
If you want to make sure your plant isn’t exposed to colder temperatures, you may want to keep them away from windows. In colder months like late fall and winter, even the smallest draft can leak cold air into your home through cracks in your windows. While this air usually dissipates and warms up as it travels throughout your home, any plants placed in close proximity to the window will be affected. Move your tropical plants into an area where they will still get bright but indirect light, while making sure they won’t be affected by potential drafts.

Tip #2: If You Find Dry Patches, Your Plant May Be Getting Too Much Sunlight or Heat
You may notice the leaves become white or even scorched on a sunny day. These discolorations and unusual markings usually indicate that a plant is getting too much heat or sunlight, and it may be dehydrated. Excess light and heat will dry out the soil, stopping plants from getting the moisture they need to support their cellular structure. It also slows down or stops the process of photosynthesis, further hindering growth. If ignored for too long, these dry spots can spread and eventually result in the death of your plants.

Tip #3: Avoid Frost at All Costs
Colder temperatures and frost can damage your plants by causing ice crystals or disrupt normal physiological activity. This makes it nearly impossible for water to move freely throughout plant tissue, creating a deficit of moisture in their stems and leaves. You can tell a plant has been damaged by frost if it begins to suffer from hydrosis (it will appear as though it's soaked with water.) If the problem persists, your plants may begin shriveling and turning a dark brown or black hue. After that, the plant will almost certainly die.

The best way to maintain the right temperature range for Garden petunia is by keeping an eye on both the climate and humidity. You’ll want to try to keep each species in a room where you have access to climate control, keeping the heat in the temperature range best mimics its natural habitat. The humidity levels will also have a direct effect on temperature, so it's important to monitor these as well. You can artificially raise the humidity of your growing space by using a humidifier or lightly misting the leaves with water.

If you intend to grow this species outside, you may find it difficult to maintain the right balance of temperature and humidity. If temperatures begin to drop or the air becomes too dry, your best option is to find room within your home and move your plant inside. An indoor growing space will allow you to control the climate more closely, helping your plant reach its full potential.

For this tropical plant to thrive, you’ll want to keep them between 75°F and 90°F (25-30°C). Each species can handle temperatures outside of this range, but keeping it within several degrees of these limits will ensure they grow to their maximum potential.

As for its extreme temperature limits, any environment below 41°F (5℃) or above 104°F (40℃) will begin to hinder its growth and cause various aberrations to its leaves and stems. This is especially true with low temperatures; even a light frost can cause your tropical plants to perish. Cellular death can begin to happen at a rapid pace, with some species dying in as little as 12 to 24 hours.

Garden petunia is easy to care for in the spring. Since the plants do not grow in soil, repotting isn’t necessary.

Tip 1: The plants do require indirect sunlight and misting two times a week, but do not allow water to stay on the leaves.

Tip 2: Fertilizer monthly with a plant food formulated specifically for air bromeliads.

Tip 3: Garden petunia requires indirect sunlight, move the plant to a sunny location, away from breezes.

Tip 4: Look for any pups – small plantlets growing from the parent plant. Carefully separate the pup and place it in another container to propagate Garden petunia.

Summer care for Garden petunia is similar to spring.

Tip 1: It includes ensuring the plant is not receiving direct sunlight that can burn the leaves.

Tip 2: Water or misting twice a week will encourage healthy growth, along with a monthly application of fertilizer formulated for air bromeliads.

Tip 3: Remove any large offshoots and repeat the same care for the smaller plants.

Tip 4: Repotting the offshoots is an easy way to propagate Garden petunia. Gardeners can remove both the large and small pups growing from the parent plant.

Keep up the care for your growing Garden petunia throughout the fall.

Tip 1: Water your plant to keep it moist, but reduce watering to about once every two weeks.

Tip 2: Make sure the soil is moist, including misting if your plant is thirsty. As the weather turns colder, avoid letting water cling to the leaves.

Tip 3: Continue fertilizing monthly with a bromeliad mixture, and ensure the plant has access to strong indirect sunlight.

Tip 4: You can propagate during this season, as well, trimming away offshoots and placing them on wood to allow them to grow and thrive.

Providing a suitable environment for your Garden petunia will help it survive the cold winter.
Tip 1: Reduce watering your Garden petunia in the winter to once every two weeks, and be sure to drain or brush away any extra moisture that can cling to and harm the plant during this season. Ensure it's kept moist, not soggy.

Tip 2: Place the plant in strong indirect light. You can also fertilize it a few times with a bromeliad fertilizer throughout the season.

Tip 3: The plant will grow outdoors in warmer winter climates or if brought indoors in freezing weather, which will also protect it from the colder temperatures this season typically brings.