Why do bonsai leaves turn yellow?

Yellow leaves on your bonsai indicate stress in the plant and need to be addressed as soon as possible. The most common cause of this stress is that you are over-watering your bonsai. Overwatering means that the roots are suffocating in the wet, soggy soil. Poor drainage also contributes to stress, as stagnant conditions exist within the pot. Yellow leaves that uniformly cover the plant could indicate a deficiency of nutrients, such as nitrogen.

Diagnosis can be made by studying yellowing patterns. Even yellowing likely means an issue with nutrients. Spotting yellow means an insect issue. Yellowing at the edges and tip of a leaf indicates an underwatering issue. When I found spider mites on my ficus, I knew because I discovered tiny yellow speckles on each of the leaves. Always inspect under the leaves.

Take corrective actions according to the cause. If overwatering is the issue, cease irrigation and repot immediately. If pests are present, treat with organic sprays in the beginning stage. If you have nutrient issues, consider reducing fertilizer if you think more might help. If the plants are in shock, stabilize temperatures. Make note of any changes every week.

Reduce the chances of recurrence with proactive plant care by checking soil moisture daily with your finger, ensuring adequate light exposure, introducing well-draining soil mixes, quarantining newly acquired plants, and other preventive measures. All these steps will help maintain healthy, sustained foliage.

Read the full article: How to Care for Bonsai Tree: Essential Guide