💧 Watering Interval Estimator

This gives a general starting-point estimate for how often to water, based on pot size, material, light, and season. It's a guideline, not a substitute for checking actual soil moisture — always feel the soil an inch or two down before watering.

General estimate only — always check actual soil moisture before watering.

The arithmetic, in full

A base interval from pot diameter, multiplied by three fixed factors:

base days = 3 + 0.5 × pot diameter (in)
days = base × material × light × season
material: terracotta 0.85, plastic 1, glazed ceramic 1.1
light:    low 1.3, medium 1, bright indirect 0.85, direct sun 0.7
season:   winter 1.4, spring/autumn 1, summer 0.85

A 6 in plastic pot in medium light in spring gives 3 + 3 = 6.0 days flat. The same plant in terracotta, direct sun, in summer comes to 6 × 0.85 × 0.7 × 0.85 = 3.0 days; in a glazed pot in low light in winter it is 6 × 1.1 × 1.3 × 1.4 = 12.0. The light menu offers both “medium / bright indirect” at 1 and “bright indirect (near window)” at 0.85; pick the second at the glass.

Why no schedule can be right

The five multipliers leave out most of what sets drying time: soil mix, species, temperature, humidity, airflow and how root-bound the plant is. A chunky aroid mix dries in a third the time of dense peat, and a snake plant wants water a fifth as often as the fern beside it. Treat the number as a reminder to check, then decide by finger an inch into the soil, or by the pot's weight.

Watering on a fixed calendar is the commonest way houseplants are killed. Roots need air as much as water, and soil kept constantly wet suffocates and rots them. A thirsty plant wilts and recovers within hours of a drink; a rotted one does not come back.

Frequently asked questions

How often should I water a houseplant?

There is no fixed answer, which is why this returns a starting point, not a schedule. For a 6 in pot it spans 3 to 12 days. Check the soil then, rather than watering on the date.

Do terracotta pots need watering more often?

Yes. Unglazed clay is porous and loses water through its walls, so the estimate shortens by 15%. Glazed ceramic seals the surface and stretches it by 10%.

How do I tell if I am overwatering?

Yellowing lower leaves, soil that stays damp for over a week, fungus gnats and a sour smell. Wilting with wet soil is rot, not thirst, and more water makes it worse.