Why do petunias die? Causes and how to avoid it

Petunias, are they easy plants to care for? It seems so, because the seeds germinate relatively quickly and, just a few months later, they flower almost without any special care. However, sometimes they turn yellow, then brown, and finally we lose them. Why?

Because even the easiest plants to care for can suffer irreversible damage when their needs are not met. Because, Let’s answer the question why do petunias die?explaining the causes and how you can avoid them.

Cold

Depending on the area and the climate, the petunias They can get bad as soon as the cold arrives. They are plants of tropical origin, therefore, very sensitive to low temperatures. In fact, they only resist up to a minimum of 14ºC. This means that if we leave them in the patio or on the balcony during the winter and the mercury in the thermometer drops too low, our plants will wilt and end up dying.

How to avoid it? It’s simple: putting them in the house when it starts to drop below 18ºC. To stay tuned, you can occasionally check a meteorology website in your country (such as the AEMET if you are in Spain), or better yet, buy a basic domestic weather station, like this one:

It costs just under 15 euros, and It helps you both to know the temperature and humidity inside and outside. It will be very useful to know about humidity, because if you grow plants of tropical or subtropical origin, such as calatheas, phytonia, philodendron, pothos, etc., you should know that they need to be high; and if it happens that the one there is low, below 50%, then you will have to spray them with water so that the leaves do not turn brown.

But yes, if you bring your petunia inside, put it in a room where there is a lot of lightbut away from heating, air conditioning, and others, because the air currents generated by these devices dry the leaves.

Excess irrigation

Irrigation is a touchy subject. Water is life, but an excess of it kills any plant, unless it is aquatic. But petunias don’t need frequent watering. But they are also not plants that can be put in pots without drainage holessince if it is done, the roots will rot since the water remains stagnant inside said container.

It is something that I have seen a lot: you buy a petunia in a small pot, and the first thing you do is put it inside a pot, which, yes, is nice, but it can end the life of the plant. Therefore, this must be avoided. Let’s leave the pots without holes in their base for the aquatic onesand plant the rest in containers with holes, otherwise, they will soon show these symptoms:

• Yellow sheets: first the oldest, and then the following.
• Mushrooms: white or grayish mold on stems and/or leaves.
• the flowers are spoiled: they do not open or fall prematurely.
• Verdine: appears when the soil remains wet for a long time.

To do? First of all, we must suspend the irrigations, and later if we have it in a pot take it out of there. We will wrap the ground bread with absorbent paper, and leave it in a dry place for at least twelve hours. After that time, we will plant it in a new pot that has holes in its base, with a new culture substrate.

In case it is in the ground, and since it is a small plant, we will remove it by making several trenches about 30 centimeters deep. so you can come out with the whole root ball. Then, we will proceed to wrap its roots with absorbent paper, and the next day we will plant it in a pot. When it has recovered, that is, when it produces new and healthy leaves, we can plant it back in the ground, but this time, we will make a hole of about 40 x 40 centimeters and fill it with a mixture of universal substrate with perlite.

Lack of irrigation

Petunias also do not support drought. But beware, when we talk about drought we are referring to a problem that can be caused either by a lack of rain or irrigation, or by the (poor) quality of the substrate or land in which they grow. That is, these plants They can dry out either if they receive less water than they need, or if the soil is so compact that it is unable to absorb the water..

Therefore, dehydration can also affect them a lot, causing these problems:

• Yellow sheets: The newest ones will start to turn this color, and then the next ones.
• The flowers do not open: lacking moisture, they cannot do it.
• The earth is very dry: it can even be seen as very compact, to the point that when you pour water into the pot it runs out quickly from the sides, and if you water the soil a small puddle forms that takes a long time to disappear.

In order to solve it, if it is in a pot, it will be placed in a basin with water for half an hour or more; and if it is in the garden, a tree grate around and it will water. In the event that the soil has become very compact and does not absorb water, it will be planted in a new place (in another pot, or in another corner of the plot) with universal growing medium mixed with 30% perlite.

And from then on, it will be watered more often.

Pests

The pests that most affect petunias are: thrips, aphids and whitefly. These are parasites that feed on the sap of the leaves, which is why they cause discolored spots to appear on them. When left unchecked, they can greatly weaken plants. Therefore, treatments should be carried out as soon as we see them badly, or even before, as soon as there begins to be any of these insects on the underside of the leaves and/or on the flowers.

How to treat them? With the best homemade insecticide that exists, of course: the diatomaceous earth. And no, it is not a joke. Diatomaceous earth is an ecological product that leaves no residue and is not toxic to humans or the vast majority of animals, only to small insects like the ones we just mentioned. To use it, you just have to wet the petunia with water, and then add the product as if you were adding salt to a salad. Here is a video in which we talk about it:

Diseases

Petunias do not usually have diseases on their own. I mean, it is very difficult for a healthy one to have any, unless it receives more water than it needs, or if the soil is of poor quality and does not allow the roots to develop normally. So when this happens, are fungi such as botrytis, powdery mildew or phytophthora that rot leaves, stems, flowers and/or roots.

Unfortunately, there is not much that can be done, since when the symptoms appear (white mold, brown spots, flower drop), it is usually too late. However, it is possible to try to save them by applying copper-based fungicideAs this, planting them in light soils that drain water well, such as that of Flower or Boom Nutrients, and avoid using pots without holes.

Lack of nutrients

One of the problems that petunias usually have is chlorosis; that is, the leaves turn yellow except the nerves that remain green. This is due to the iron deficiency, and occurs when planted in soil with a pH of 7 or higher, or irrigated with alkaline waterwith a lot of lime.

To prevent them from dying, in addition to planting them in suitable land and watering them with water with a pH lower than 7, they must be fertilized with specific liquid fertilizers for these plants, and this, or with an organic fertilizer such as guano. We will follow the instructions on the container at all times, so that little by little we will get new and green leaves. Unfortunately, the ones that are already yellow will dry out and drop, but the petunias will thrive.

We hope that these tips will help you to have beautiful petunias.