When plant leaves are changing color they are trying to tell you something. The pattern of discoloration and color are signs of underlying causes. Most of the time inadequate watering leads to yellowing leaves on houseplants or greenhouse plants.
That is why it is vital to learn how to water plants. Drip irrigation will do well in a greenhouse. However, there are different watering systems that meet individual needs. Sometimes lack or excess of nutrients leads to plant leaves discolorations.
For example, if the tips and center vein of the leave are turning yellow, it is a sign of nitrogen deficiency. If leaves turn purple, that is a symptom of phosphorus deficiency. It is very important to check on your plants regularly to identify nutrient deficiencies early.
Although it is not common, but plant leaves can turn white. In this blog post we will discuss why plant leaves are losing color and turn white. You will find out what to do if plant leaves are turning white and how to prevent it.
So, why are plant leaves turning white?
If you noticed a white coating on the leaves and stems of a plant, it is affected by powdery mildew. However, if plant leaves are long, the growth is leggy and stems are weak, your plant gets very low light. The stems and leaves are also turning white in color.
Let’s look at the reasons why are plant leaves turning white in more details. We are also going to discuss the underlying causes.
What causes plants to turn white?
Reason #1 – Powdery Mildew
Powdery mildew is a fungal diseases. It forms a powdery gray or white coating on the leaves and stems of the plants. Many different species of fungi in the order Erysiphales can cause powdery mildew. It starts with a few spores on the leaves and fungi quickly spread covering the surface of the plant.
It affects many garden plants including apples, blackcurrants, gooseberries, grapes, strawberries. Some vegetables like cucumbers, marrows and zucchinis are also affected. Powdery mildew is a major problem when growing cereal crops.
Although powdery mildew causes little damage, it can result in leaves yellowing and dropping. Chemical fungicides are effective in treating powdery mildew because it mainly affects plant surface. Go for a natural, organic fungicide like SaferGro to spray edible crops.
Powdery mildew thrives in humid conditions and in temperatures between 60°-80°F, so you need to manage humidity and leaf wetness. Choose the best location for planting – full sun where possible. Space plants well apart to ensure good air movement. Follow these steps to prevent this disease.
Reason #2 – Very Low Light
When plants grow in partial or complete absence of light, they stretch to get as much light as possible. The elongation of plant stems growing in the dark is called etiolation. It is a process that increases the chances of the plant to reach the sunlight.
Indoor houseplants put in very low light will show long, leggy growth and weak stems. Moreover, stems and leaves become pale in color, usually white or yellow. The lack of chlorophyll causes the dark-grown plant turn pale in color.
Chlorophyll is the pigment in leaves that makes them green. A condition in which leaves produce insufficient chlorophyll is called chlorosis. The causes of chlorosis include poor drainage, damaged roots, compacted roots, high alkalinity and nutrient deficiencies.
If you place houseplants very close to each other, it can cause etiolation. Moreover, if the plant is overgrown or put in low light, plant will stretch to find light from a nearby window. Moving a plant to a brighter location will resolve the issue.
To prevent etiolation and chlorosis you need to select a site with proper light. Also, test the soil for nutrients by sending it to a soil testing lab. Make sure to test soil pH so it’s not highly alkaline. Get 3-in-1 soil meter to monitor pH levels and light intensity.
Also, space your plants appropriately whether you are growing in the garden, greenhouse or indoors. Keep up with regular pruning and make sure that you prune properly. It will ensure that sunlight penetrates all plant surfaces as best as possible.
Reason #3 – Ozone Damage
Ozone is a damaging air pollutant to plants. Ozone is produced when UV radiation strikes molecules of oxygen (O2) and oxides of nitrogen spontaneously generate ozone (O3). It enters leaf openings called stomata and oxidizes or in other words burns plant tissue during respiration.
How severe the damage is depends on the concentration of ozone, how long it was affecting the plant and how sensitive your plant is. Sometimes damage results in irregular lesions that may be tan, white or dark brown in color.
Also, another common symptom of ozone damage is bleaching of the upper leaf surface. Unfortunately, there is no treatment for ozone damage. However, you can incorporate different management strategies to prevent problems.
Generally, if you keep plants in good health at all times, they resist damage better than weakened plants. So, make sure that you are watering during drought periods. Fertilize according to soil analysis. Use the best soil for greenhouse plants and make sure that it’s porous, well-draining and is not compacted.
Plant leaves that change or lose color try to tell you that something is not right. Look carefully at the plant leaves and study the discoloration. If you noticed that leaf is covered with white coating, your plant is most likely infected with fungus causing powdery mildew.
Treatment includes the use of fungicide but it is better to prevent the problem. Choose the best location for your plant and monitor humidity. However, if the leaf lost color, it can be due to lack of chlorophyll caused by low sunlight.
Make sure to place your houseplant in a well-lit spot and prune it regularly. Sometimes plants especially trees can suffer from ozone damage. There is nothing you can do to treat it but maintain general plant health, so it is more resistant to damage.
Do you have plants in your garden or indoors that are turning white? Let me know in the comments section below!
Happy Growing 🙂