How do self-watering pots work?

Water is stored in a reservoir at the bottom. A wick or capillary mat draws water up to the roots as needed, providing consistent moisture.

How big should the reservoir be?

Approximately 20% of the total pot volume. Too small and you refill too often. Too large and it takes away from root space.

How often do I need to refill?

Depends on pot size, temperature, and plant type. In summer, a 30cm pot may need refilling every 3-5 days. In cooler weather, weekly.

Can I make a DIY self-watering pot?

Yes. Use a container within a container, with a wicking system (fabric strip) connecting the reservoir to the soil. Many online tutorials available.

How do self-watering pots work?

They have a reservoir at the bottom. A wick or capillary material draws water up to the roots as needed. You fill the reservoir through a tube and the plant waters itself.

GardenCalcs

Self-Watering Pot Calculator — Reservoir Size & Refill

Calculate reservoir size and watering frequency for self-watering pots.

Pot Diameter

Pot Depth

Average Daily Temperature

How We Calculate This

Pot volume = π × r² × depth. Reservoir = 20% of pot volume.

Daily water use = 5% of pot volume × temperature factor (0.7 for cool, 1.0 moderate, 1.2 warm, 1.5 hot).

Refill interval = Reservoir size ÷ Daily water use.

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.