Brown Stems on Moth Orchids

Brown Stem During Bloom

• While the moth orchid is putting out flowers, the stem should stay strong and dark green in color. The presence of brown spots, streaks or patches on the orchid's stem indicates a disease problem that might kill the blossoms or stop the orchid from putting out new flowers. The factors that lead to the stem turning brown include fungal diseases present in the soil, such as root rot. Properly caring for an orchid with a brown stem can save it.

Treating Moth Orchids with Fungal Diseases

• Orchids are sensitive to severe environmental changes and chemical treatments; treat moth orchids with brown stems in gradual stages to prevent the plant from suffering more severely. Fungal diseases live in the soil of an orchid's container; remove the soil from the container and get a new planter and soil for the orchid. Apply a mild fungicide targeted for use on orchids to the moth orchid to control the spread of the disease. Prune and remove any affected leaves.

Brown Stem After Bloom

• If the stem of a moth orchid turns brown after the plant blooms, this is a sign of the normal process of the orchid's growth, dormancy and life cycle. Unless the plant is prodded into producing two sets of blooms, the stem turns brown after the orchid drops its flowers; the roots of the orchid take the nutrients from the stem and use them during the brief period of inactivity between blooming seasons. Prune the stem to the level of the soil once it is completely brown.

Keeping Orchids Healthy

• Stems turn brown for a number of reasons other than fungal disease, including excess watering, sunlight or fertilization. Orchids are highly sensitive to their environmental conditions, and excess light and fertilizer contribute to a burned appearance of the stem and leaves of the orchid. Too much water drowns the orchid's roots, leading to an eventual browning of the leaves and stem as the orchid dies. Maintain a healthy growing environment for the moth orchid to keep it producing blooms.