Due to the constantly changing weather.
The effects from the 2019 El Niño event that ended approximately 7 months ago continues to affect Hawaii's weather.
While most locations is simply warmer than normal, the east side of the Big Island has been experiencing interchanging periods of extremely wet and extremely dry weather.
Container gardening has been challenging due to the constantly changing weather. Soon after I repotted both of my basil plants because they were drying out too quickly, the extremely wet weather returned.
Now both of my plants are wilting because they're suffering from a mild to moderate case of root rot. Here's what I did to remedy the situation:
Cut off the rotten roots.
Repotted the plants they were previously in.
Let the soil dry out.
Treated the soil with 1 tbsp of hydrogen peroxide that was mixed in 1 cup of purified water.
What's ironic is I always have two containers of each type of plant just in case this happens. What's extra ironic is my younger bushier plant is faring worse than my older sparse plant that I was planning on replacing in March. Luckily, non of my other plants are suffering from root rot.
February 15, 2020 update: Both of my plants has successfully recovered from root rot.