If the flower spike turns yellow then it's a sign there is something slightly wrong, but not necessarily life threatening for the orchid. ... Just so you don't have to look any further, the reasons that orchid stems yellow are overwatering, too much sunlight, fungal infections, and nutrient deficiency.

What do I do if my orchid stem is yellow?

Orchid stems turn yellow due to overexposure to direct light, overwatering, or bacterial and fungal infections. But, if it's only the part of the stem holding the bloom that has turned yellow, the flower spike is dying out. Cut down the yellow flower spike to let it dry out and fall off by itself.

Should I cut the yellow stems off my orchid?

Don't remove them from the plant yourself! Some people remove them because the look of yellow leaves is unsightly. Manually removing the leaves from your plant increases the risk of diseases.