Why Are My Petunias Leaves Turning Yellow?
If the petunias on your windows suddenly turn yellow leaves and no longer look very decorative, then they are dealing with chlorosis. Like all our plants, our balcony flowers need the right nutrients to grow magnificently. If the leaves on your Petunias turn yellow, especially the young leaves, then it is most likely chlorosis, which is caused by a lack of nutrients.
Recognize chlorosis in petunias
The missing nutrient is iron (Fe-Ferrum). A typical symptom of chlorosis in petunias is the green leaves turning yellow, but the leaf veins remain green. Plants need iron for the formation of enzymes, for metabolism, for the formation of chlorophyll, and thus also for respiration and photosynthesis.
If this nutrient is now missing, however, not only the recognizable discoloration occurs, but due to the lack of chlorophyll, photosynthesis is impeded and the plants can also no longer form certain enzymes and hormones. If the petunias on your windows suddenly turn yellow leaves and no longer look very decorative, then they are dealing with chlorosis.
Like all our plants, our balcony flowers need the right nutrients to grow magnificently. If the leaves on your petunias (Petunia) turn yellow, especially the young leaves, then it is most likely chlorosis, which is caused by a lack of nutrients.
Here’s how to recognize an iron deficiency in your petunias or surfing as:
- Young leaves are affected
- The leaves turn yellow, only the leaf veins remain green
- Growth disturbances
Preventing chlorosis in petunias
In order to avoid problems with chlorotic petunias due to iron deficiency, we have prepared a few tips for you below. Since petunias are so-called heavy feeders, they need a lot of nutrients and also a lot of water.
However, you should also pay attention to the watering water. If you always water the petunias with hard water from the tap, i.e. water that contains a lot of lime, the pH value in the soil can change.
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A change in pH can mean that certain nutrients – such as iron if the soil pH is too high – can no longer be absorbed, or can only be absorbed to a much lesser extent. Therefore, you should use soft water (rainwater) for watering if your tap water is very rich in lime.
When planting, already use a loose and nutrient-rich substrate to give your petunias a good start in life. Especially for petunias in containers that show symptoms of chlorosis, repotting in fresh soil can also be helpful.
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This will give the plant fresh nutrients again, as a lot of watering, can flush out many nutrients that the plant needs. Repotting after overwintering is also beneficial and recommended. Here you can learn more about proper care and overwintering petunias.
Lime and pH: What else you should know about it
There is always a lot of talk about pH and lime, so what is it all about? The pH expresses the concentration of hydrogen ions, so the more hydrogen ions there are, the more acidic the solution.
You will always find the terms acidic, basic, alkaline, and neutral in connection with pH:
- basic and alkaline mean the same thing, namely a pH above 7.5
- neutral means a pH value of 6- 7.5
- Acidic means a pH value below 6
For plants, the pH of the soil is important for the availability of nutrients or also called nutrient salts. The optimum pH for most plants is between 5.5 and 6.5. Extreme pH levels can damage plant organs. Also, extremely high or low pH levels are responsible for nutrients being fixed in the soil and unavailable to plants.
An elevated pH causes a deficiency of phosphorus or iron, whereas a low value results in a deficiency of magnesium or molybdenum, for example. This nutrient deficiency is caused by the unavailability of these nutrients and is caused by the pH.
Water hardness is determined by calcium and magnesium carbonates and has a basic effect. As a result, the pH of the substrate can be influenced and this is done by water.
Treat your petunias with special surfing and petunia fertilizer. These NPK fertilizers contain nitrogen (N), phosphorus (P), and potassium (K), as well as iron (Fe), which are needed to the greatest extent, and help your flowers to grow.
Petunia fertilizers you can apply regularly, depending on the fertilizers used. In this way, you can also prevent deficiency symptoms. Since iron can be absorbed by petunias through the roots and through the leaves, foliar fertilization can also be used to combat iron deficiency.
Foliar fertilization for petunias
You can also use special fertilizers containing iron on your petunias. These fertilizers also contain nitrogen to support growth. When you spray the leaves with iron fertilizer, you should avoid direct sunlight.
Therefore, it is recommended to apply in the evening. Foliar fertilization is an optimal way to combat iron deficiency, as this fertilizer cannot be washed out with the water used for watering. However, be careful with the dosage: overdosing can cause even greater damage to your petunias. Also, avoid contact with the fertilizer solution, because these iron fertilizers can leave unsightly rust stains on your clothes or on your floor.
Rock flours for petunias
In addition, rock flours can be brought into the soil to compensate for iron deficiency. Rock flours can also be brought in during planting in order to supply the petunias with nutrients right from the start.