A houseplant may turn yellow for all kinds of reasons. This typically happens when the leaves have lost their nutrients and photosynthesis capabilities. Mild yellowing in isolated parts of the plant may be something that’s easily remedied and unlikely to kill the houseplant. Nevertheless, you shouldn’t ignore the problem when a houseplant is turning yellow, as it may be a symptom of more serious trouble ahead.
Much of the time, you can confidently figure out the problem by looking at the timing and circumstances of the discoloration. Take a look at the following reasons why a houseplant is turn yellow, and consider what’s changed recently in your houseplant care or seasonal conditions.
Most Common Reasons Houseplants Turn Yellow
Not Enough Light: The chlorophyll that makes plant leaves green will catch sunlight and use it for photosynthesis, but the sunlight also stimulates the production of new chlorophyll pigments in the plant. In other words, if a houseplant isn’t getting enough light, the chlorophyll can’t do its job and stops give the leaves their natural green color. The nutrient loss and stunted growth often cause the houseplant leaves to turn yellow. If the plant is already in a window with lots of light, consider whether it’s a dried brownish yellow that’s the result of burning under the sun. Again, looking at the plant’s general living conditions will often reveal the source of the discoloration.
Overwatering/Root Rot: Leaves that are bloated with water may turn a translucent yellow. Overwatering may have also caused root rot which is cutting off nutrients to the growth that depend on this part of the root system. If you have entire areas of the plant, from stem to leaf turning yellow, this is likely the cause. To be sure, expose a portion of the roots under the yellowing houseplant. The roots should be white and firm. If they are soft and brown, this is root rot. You should reduce the watering schedule, but you will also need to remove the affected part of the plant, which is unlikely to recover. Underwatering plants may also cause yellow discoloration, though a brown color is more likely with soil that’s too dry.
Water and Soil Quality: Leaves that turn yellow especially at the tips may have something to do with the type of water you’re using on houseplants. Some tap water has higher levels of fluoride or alkaline minerals that rarely kill a houseplant but can interfere with the roots ability to absorb water and deliver nutrients to all areas of new plant growth. Think about switching to filtered water, or let the watering can sit for 24 hours to reduce the chemicals and minerals in the water. Too much and poorly timed fertilizer will also cause disruptions to water and nutrient absorption and is another common reason houseplants turn yellow.
Pests: Whether it’s some type of scale or plant mite, houseplant pests have a knack for boring their way into your plants and stealing the nutrients stored in their leaves, stems and/or roots. This nutrient loss may eventually cause the plant to die back in a major way, but often the first sign is houseplant leaves turning yellow. Be sure to check for tiny spots and other signs that your houseplant has pests. Take immediate action to remove as many of the pests as possible and begin a regimen of insecticidal treatments.
Temperature: Most indoor plants can tolerate modest swings in temperature between summer and winter. However, it’s not a good idea to leave tropical plants near vents where air conditioning will periodically blast the plant with cold, dry air. If it gets cold enough for long enough, the plant can turn brown and die back altogether. Periodic drafts are more likely to turn houseplant leaves yellow.
Houseplant Turning Yellow: Look at the Type of Plant
As part of diagnosing why your plant is turning yellow, it’s often helpful to know what type of plant you’re dealing with. Full shade plants are less likely to suffer from insufficient light unless they are far away from windows. Bromeliads are more pest-resistant than most types of houseplants. Azaleas, begonias, and African violets all tend to prefer acidic soil and are more likely to be affected by alkaline soil from tap water.
Yellowing leaves is one of the most common signs of distress in a houseplant. In some cases, it can be helpful to review why houseplants turn brown. Once you understand the underlying cause of the discoloration, it’s usually easy to find out what treatment and recovery steps may be taken to return the houseplant to full health.