The answer to 'why is my sod mud' is that your new sod is likely oversaturated with water, causing it to become muddy and soft. This can happen if the sod was not properly installed or if there has been excessive rainfall or irrigation.
Some common causes of sod mud include poor soil preparation, improper grading, excessive watering, and heavy foot traffic. Symptoms include a squishy, spongy feel underfoot and visible pooling of water on the surface. To fix this issue, you'll need to address the underlying cause and take steps to improve drainage and soil quality.