Prevent Pot Cracking: Tar-Coat the Inside

The Freeze-Thaw Cycle

Water enters porous clay or concrete pots, freezes, expands, and cracks the pot. Painting the interior with roofing tar (or waterproof sealant) creates a moisture barrier.

How to Do It

1. Clean pot thoroughly; let dry completely.
2. Brush tar generously over entire interior surface.
3. Let cure 24–48 hours before adding soil.

Extra Protection for Bulbs

Move pots to a protected area (garage, shed, against house) during deepest cold. Hardy bulbs still benefit from insulation—wrap pots in burlap or bubble wrap if they must stay out.

Why This Works

Landscape architects use this method for client installations. It’s cheap, permanent, and allows you to reuse decorative pots year after year.