My Cymbidium Orchid Leaves Are Turning Yellow

Environmental Care for Cymbidium Orchids

• Cymbidium orchids grow best in high sunlight. Keep the orchid where it receives adequate light, but keep in mind that excess sunlight damages the leaves, turning them yellow. Orchids also require a relatively high temperature and humidity; temperatures that drop too low and air that becomes too dry both contribute to the yellowing of cymbidium leaves. Orchids also require regular applications of fertilizer to the soil to remain healthy and produce both leaves and blossoms.

Bar Mottle on Cymbidium Orchids

• Bar mottle is a serious viral disease that has the potential to affect cymbidium orchids and turn the leaves yellow. The virus gets its name from the way the leaves yellow, as they exhibit bars or streaks of yellow due to the spread of the virus. Bar mottle also has the potential to affect the petals of the cymbidium, causing them to become warped or stunted. Destroy infected plants to prevent the disease from spreading.

Scale Insects on Cymbidium

• Scale insects are attracted to the leaves of the cymbidium orchid, where they feed and create small scaly shells for themselves. As scale insects feed on the cymbidium's leaves, the leaves lose nutrients and begin to turn yellow. Additionally, the substance secreted by scale insects can bring sooty mold to the garden, causing further problems for the orchid. Treat scale insects with a pesticide and prune leaves that are severely affected by the insects.

Watering Cymbidium Orchids

• Cymbidium orchids are epiphytes, which means that they grow without soil in the wild; instead, they attach themselves to a tree. Use a loose, fast-draining material like wood chips, charcoal or perlite and sphagnum moss, which helps retain moisture, according to the Colorado State University Extension website. Excess water or insufficient water both contribute to the yellowing of leaves; water the cymbidium orchid once every seven to 10 days to keep its leaves green.