The answer to 'hardwood floor moldy' is that mold on hardwood floors is a common problem caused by excess moisture, poor ventilation, or water damage. Symptoms include discoloration, a musty odor, and visible fungal growth. Solutions depend on the extent of the mold, but typically involve removing the mold, addressing the moisture source, and restoring the floor.
For minor mold, you may be able to clean the floor yourself using a vinegar or hydrogen peroxide solution. However, for larger affected areas or if the mold has penetrated deep into the wood, it's best to call in a professional cleaning service. They have the expertise and equipment to properly remediate the mold and prevent it from recurring.