Related Clues:

• Make muddy
• Flowerpot filler
• Lower in dignity
• Make impure
• It's not needed in hydroponics
• 4-H Club concern
• Upper crust?
• Farmer's earth
• ''___ funny, McGee!''
• Lower the value of, as currency
• Bedrock's covering, perhaps
• Ruin morally
• Make grimy
• Opposite of purify
• Befoul