Why Are Orchid Roots Turning Black? Causes and Solutions

There are many situations in which orchid roots turn black, and it is not possible to determine the cause from one single aspect. Flower lovers can refer to the information below to make a judgment.

1. The part where the leaf joins the pseudobulb is generally called the leaf base or leaf sheath. If the leaf sheath turns black, it indicates stem rot caused by bacterial infection, which must be taken very seriously. You can immediately use agricultural chloramphenicol or streptomycin at 2000 times dilution, or captan at 500 times dilution, to spray and drench the leaf base and pseudobulb. Alternatively, choose the broad-spectrum agent 70% Jingfuling emulsifiable concentrate.

How to use: Use this agent at 600 times dilution (the amount can be adjusted according to how many orchids you have), once every 7—10 days, spraying 4 times in a row, then depending on the situation spray once every 15—20 days for preventive spraying; during the high-temperature period from April—October, use this agent for prevention.

2. If the roots are turning black, it is mostly caused by excessive water and poor air permeability of the potting medium. This situation is mostly caused by improper management. Flower lovers can troubleshoot various causes such as water damage, fertilizer damage, improper water use (pH, contaminated water), and improper medium ratio.