So, you probably thought you were a green thumb because you’ve been tending to your own plants for a while now. Everything seemed normal for a while until you noticed the leaves on some of your plants were beginning to turn pale and almost white.
What could have gone wrong? Why Are My Plants Leaves Turning White?
The information I’ve shared in the guide below should help you assess the conditions of the plants in question as well as their environment. We’ll also mention several proper care procedures you can employ to improve your chances of successfully taking care of your plants in the long run.
Why Are My Plants Leaves Turning White?
The reasons your plant leaves might be turning white boils down to three reasons. I’ll give the summary version here, then elaborate further in the next section. One, your plant could be sunburnt. Two, it could be infected. Three, it could be suffering from chlorosis.
That’s about it. See. Simple Answers.
Maybe your plants are sunburnt, explaining why their leaves may be turning white. This tends to happen to a wide array of plants because they weren’t hardened off long enough before they were planted outside.
In other words, you didn’t give them sufficient time to acclimate to the sun outside before you placed them out there permanently.
A common mistake that most of my readers tend to make is thinking that because they moved their plants from a greenhouse to the outside sun, that it didn’t need any acclimation time. This couldn’t be further from the truth.
Greenhouse panels filter UV light, while direct sun usually has no filters. This implies that direct sunlight will beat down on plants on the outside just like it does on us, and new plants aren’t the only ones that can suffer from this.
If you live in an area such as Phoenix, where extended heatwave periods tend to strike, sunburnt injuries could be why your plant’s leaves are turning white.
With that in mind, what can you do when this happens? Unfortunately, not much. Simply cut the leaves off and give your plants all the love they need until they can grow new, healthy leaves. You could also try putting up a UV sunshade if your area goes through an extended heatwave.
I’ve also personally used temporary sunshades that filtered the UV light, and the trick did wonders protecting my peppers from the scorching afternoon heat and sunlight.
If the plants in question are new ones, you can also start with baby steps and only award them a short period of time in the direct sun each day. Think of this as the hardening-off process.
Over several weeks, you can expose your plants to more and more sun until the plants are sufficiently tough to withstand the intensity of sun rays in your area.
Around five years ago, I noticed something I had never seen before in my sister-in-law’s garden. It was scattered instances of plant leaves turning white.
The plant’s leaves had been green their whole life up to that moment, but their tips were now turning white, and within a few weeks, entire leaves and branches had turned white.
After consulting with experts in the neighborhood and online, we learned that the condition is called chlorosis, which simply means that the plants were not producing sufficient chlorophyll to look green.
Since chlorophyll uses sunlight to make food for the plant, the experts we consulted also pointed out that the plants might have been in distress.
Well, depending on the plant, the causes of chlorosis are wide-ranging. Here are a few you should have in mind:
- Presence of any number of bacterial pathogens like Pseudomonas syringae. These bacteria pathogens tend to cause complete chlorosis on some plants, like those in the Aster Family.
- Ozone injury if you deal with sensitive plants
- Exposure to sulfur dioxide, especially if you live in Pittsburgh
- Pesticides, paritucarly herbicides, might cause chlorosis to both the weeds you’re targeting and the crops you’re trying to treat
- Compacted or damaged roots
- Waterlogged (poor drainage) roots
- A soil PH that has made minerals absorption by the plants’ roots impossible
- Deficient proteins and or nitrogen
- A specific mineral deficiency in the soil, such as zinc, magnesium, or iron
If you suspect chlorosis could be the main culprit behind your plants’ leaves turning white, consult an expert and start fixing the issue before your plant dies off.
If you spot white stuff on your plant’s leaves, you’re probably dealing with powdery mildew. Just like its name suggests, this fungus usually covers plant stems and leaves with what appears to be powdered sugar.
I’ve dedicated this section of the guide to teaching you how powdery mildew develops and things you can do to prevent it.
To ascertain that powdery mildew is indeed the issue, look for plant leaves with irregular white spots or those that look like they have been dipped in powdered sugar.
You can further confirm by checking the surrounding temperature. Powdery mildew tends to thrive on dry, warm days followed by cold and humid nights.
Knowing the list of plants that are commonly attacked by powdery mildew could also help you confirm beyond a reasonable doubt that this is the issue you’re dealing with.
These include Rhododendrons, roses, oaks, ninebark, London plane trees, Lilacs, Hydrangeas, Euonymus (Wintercreeper), Dogwoods, Crape Myrtle, and Azaleas.
Lucky for you, powdery mildew isn’t that big of a deal. The dusty white leaves are just about as bad as they will get. That said, you’ll still want to keep your plants looking fresh, so start by cutting down any affected leaves to minimize the chances of infection spread.
Consequently, use horticultural oil or fungicide just as you notice the symptoms appearing to treat the issue. Continue applying the solution in consistent intervals until nighttime humidity drops and the temperatures during the day reach 80 degrees F.
Frankly speaking, gardening is all about trial and error. Whenever an issue strikes your plants, all you can do is try looking for answers either online or from experts in your area. With time, however, you will learn from experience, which will make you a better gardener in the long run.