How do I know when to repot?

Signs: roots growing out of drainage holes, water runs straight through, plant is top-heavy, growth has slowed, or soil dries out very quickly.

Can I pot up by two sizes at once?

For most plants, moving up one size is best. Too much empty compost stays wet and can cause root rot. Exception: vigorous fast-growers.

When is the best time to repot?

Spring is ideal — plants are entering active growth. Avoid repotting in winter when most plants are dormant.

Should I water before or after repotting?

Water the plant the day before repotting. After repotting, water lightly and wait a few days before watering normally.

How do I know when a plant needs repotting?

Signs include: roots growing out of drainage holes, water running straight through, plant becoming top-heavy, slowed growth, or roots circling the rootball when removed from the pot.

GardenCalcs

Repotting Size Calculator — Next Pot Size Guide

Find the right next pot size when repotting plants.

Current Pot Diameter

Plant Type

How We Calculate This

The recommended pot size increase depends on plant type:

General houseplants: +5 cm. Fast growers: +7 cm. Slow growers/cacti: +3 cm.

Additional compost is estimated from the volume difference between old and new pot sizes.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.