Related Clues:

• Flowerpot filler
• It's not needed in hydroponics
• 4-H Club concern
• Upper crust?
• Farmer's earth
• Bedrock's covering, perhaps
• Make grimy
• Befoul
• Rooting section?
• Agrarian concern
• Where the worm turns?
• Planting dirt
• Terra farma?
• Gardener's dirt
• Poop on