Yellow or pale green leaves on your plant are usually a sign that something is wrong with your plant.
It is only not a problem if the plant should have light or yellowish leaves. Often plants with yellow fall color have light green leaves compared to other plants.
There are basically three places where yellow or pale green leaves can be found on the plant. The first and most common location is older leaves. These are the leaves that are the longest on the plant.
If the older leaves turn pale green and eventually yellow, this can be one of several problems. First, there could be too much water. Check the soil and see if it is wet and allow the soil to dry before watering again. Your soil might be dry, but the plant was overwatered a few days or weeks ago.
Overwatering in itself will cause pale to yellow leaves, but overwatering will also leech out the nitrogen in the soil. Our soils are low in nitrogen and I find that many people have never figured out how to properly fertilize their plants.
Root rot and nematodes can also cause older leaves to turn yellow. After all, leaves don’t live forever, it may just be time for the leaves to die.
If the older leaves have yellow spots, it’s probably a virus, not a cure for viruses. If the leaves are green with yellow veins, you have the classic symptom of magnesium deficiency.
The second location is younger leaves. These are the newest leaves of the plant. If the younger leaves are yellowing, it could mean the soil pH is too high, which is a common problem in Antelope Valley, especially with acid-loving plants like gardenias and camellias.
Coupled with a high pH of yellow on younger leaves, it may mean your soil is high in salinity. High salinity means too much salt in your soil. This does not mean table salt, but probably too much fertilizer, which is also a salt. Yellow young leaves can also mean that your plant has a sulfur deficiency. All of these are common problems in Antelope Valley.
If the younger leaves have yellow spots, it’s probably a virus again, and there’s still no cure for viruses. If the leaves are green with yellow veins, you have the classic symptom of an iron, manganese, or zinc deficiency.
The final location is a generalized area of the facility, such as a side of the facility or an area on a side of the facility.
If the yellow leaves are in a general area, it could be sunburn (particularly from window and car reflections) or just heat.
It could be a dog spot from male dogs raising their legs at your plants.
It could be a chemical burn from pesticides or fertilizer spilled on the plant. I’ve even seen yellow leaves where someone poured hot water on a plant.
Hopefully I’ve narrowed down the issues, now you need to investigate the conditions further and see if you can find your answer to yellow leaves.