Although most plants typically have green leaves, their color may change due to a lack of comfort. Therefore, one should first distinguish between plants for which green color is standard and plants whose leaf color may be different due to the uniqueness of the variety. 

This section discusses the first category of houseplants that have green leaves. Plant leaves turning yellow is a complex problem and cannot be reduced to just one cause. In order to give proper care to the houseplant, periodic diagnosis and preventive treatment measures must be taken.

Yellow Leaves

In some cases, an individual may notice that the leaves of their houseplant have yellowed and become drier and more brittle. Generally, a yellow leaf means a lack of good nutrition. It is noteworthy that yellowing leaves is never instantaneous. 

On the contrary, this effect spreads gradually, often starting from the edges of the leaf. From a distance, it can look like individual yellow or pale-yellow spots appearing, first on some leaves and then on the whole plant. Yellowing of the leaf plate can be due to several reasons. 

Too Much Light

Yellowing leaves can indicate an excess of light. When too much direct sunlight radiates from a leaf over a long period, it becomes the cause of plant cell death. As confirmation of this cause, it is sufficient to inspect the leaf thoroughly. 

How will this present: Sunburn will be observed only on the window side, while the rest will remain healthy.

Solving this problem: It is not difficult to solve this problem. The individual should either move the plants away from the window or put a thin cloth over the window to stop some of the sun’s rays. 

Too Much Water

The second cause of yellowing plant leaves can be excessive water supply to the soil. When the dosage of moisture is not metered, the soil in the pot is over-watered. 

How will this present: The roots cannot function effectively and close the entrance channels for water intake because of the excess water. 

As a result, fewer molecules are transported to the leaves through the vascular cells of the stem, and thus the intensity of photosynthesis is reduced. Therefore, a yellow leaf deprived of water cannot last long and soon dries up, after which the plant discards it. 

Solving this problem: A soil moisture test can confirm this reason. To eliminate this adverse effect, it is sufficient to ensure normal drainage of the soil and observe the plant’s water supply regime. Check out our guide to Watering House Plants for more information.

Wrong Soil Acidity

A third severe cause of yellowing leaves is improper soil acidity. It should be emphasized that all biological systems have a unique pH, which is a measure of the concentration of hydrogen ions. 

The more dissolved hydrogen present in a medium, the more acidic it is. Acidity is not the norm for most plants because plant cells may not function efficiently or can even die in low pH conditions. 

How will this present: The optimal range of acidity for houseplant soil ranges from 6 to 7. This means that mildly acidic and neutral environments are most beneficial to the plant. A change in pH can harm leaf color and, consequently, the health of the entire plant. 

An altered pH affects the binding of minerals and prevents them from entering the plant. In other words, if the pH is too high or too low, the plant may not get all of its nutrients, which also affects its metabolic activity. 

Solving this problem: To remedy this situation, it is suggested that the soil be tested with analytical pH meters. If the problem is detected, pH correctors and special fertilizers can shape a certain level. 

Nutrient Deficiencies

Finally, one of the most important causes of yellowing leaves is nutrient deficiencies. It is noteworthy that there is a difference between the observed effect and the types of elements that are in deficit. 

Potassium Deficient: If the plant is deficient in potassium nutrition, this is manifested by a gradual yellowing from the edges of the leaf plate: the center of the leaf remains green, while the edges take on a bright yellow color. 

Nitrogen Deficient: If the plant is nitrogen deficient, the general yellowing begins with the older leaves, gradually moving to the younger ones. In this case, the entire leaf plate turns a pale-yellow color. 

Magnesium Deficient: If yellow spots appear between the veins of older leaves, this can signify a magnesium deficiency. It is a case of yellowing spreading from the center to the edges. 

Iron and Sulfur Deficient: However, yellowing can also be a sign of iron and sulfur deficiency, but a unique pattern of leaf death is not usually observed in these cases. 

For additional tips on how to solve nutrient deficiencies which cause yellowing plant leaves, read our house plant fertilizer guide.