Why Do Houseplants Make Snap, Crackle, Pop Sounds When Watered?

Question

Dear Mr. Creed: Sometimes my houseplants make snap, crackle, pop sounds like Rice Krispies when watered. Not related to soil type—heard it in Miracle-Gro, African violet, and succulent soils. What causes this?

Answer

Why did you plant in Rice Krispies?! Just kidding.

Most good potting mixes contain porous materials (perlite, vermiculite) that make slight popping sounds as they absorb water, especially if soil is very dry. You can also see tiny bubbles percolating on soil surface after watering.

No other explanation unless your water quality is very strange.

Will Creed, Interior Landscaper
Horticultural Help, NYC