The answer to 'why is my sod weeds' is that weeds in new sod are a common problem, often caused by weed seeds already present in the soil or introduced with the sod. Symptoms include patchy growth, discoloration, and the presence of unwanted plants. To solve this, you'll need to properly identify the weeds and take steps to remove and prevent them.
The best approach depends on the extent of the weed problem. For minor issues, you may be able to hand-pull weeds or spot-treat with a selective herbicide. For more severe infestations, you may need to overseed the area, apply a pre-emergent herbicide, or even consider re-sodding the lawn. If the problem persists or you're unsure how to proceed, it's best to consult a professional landscaper who can assess your specific situation and recommend the appropriate solution.