If you came here for a number — “every 7 days” — that expectation is the single most common reason houseplants die. University horticulture guidance is blunt: there is no single watering schedule that fits all houseplants, because how fast a pot dries depends on the plant species, its growth stage, pot type and size, light, the potting mix and the conditions — all of which change (Clemson HGIC; Illinois Extension). The reliable method is simpler than a schedule, and free.
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The method: soak fully, then let it dry
- Water thoroughly until water runs out of the bottom of the pot — then let it drain and empty the saucer; never let the pot sit in the water that ran out (Clemson HGIC).
- Let the soil dry to the right depth before watering again — for most foliage plants the top inch or two; succulents/cacti dry out much further; ferns and calatheas stay lightly moist, never soggy.
- Repeat: soak → dry → soak.
Two non-negotiables: a pot with working drainage holes, and emptying any saucer or decorative outer pot — a cachepot can quietly hide standing water the plant is drowning in (Clemson HGIC).
How to tell it’s time (three free checks)
- Finger test — push a finger into the mix; if it’s dry at your fingertip (about an inch or two down), water. Checking the soil this way rather than by the calendar is the standard extension recommendation (Clemson HGIC; Illinois Extension).
- Pot weight — a dry pot is noticeably lighter.
- Surface cues — soil lightens and pulls from the pot edge as it dries (a hint; confirm with the finger test).
A moisture meter can help in deep pots; treat it as a second opinion, since cheap probes vary in reliability.
What changes how often you’ll really water
Water more often with brighter light, small/terracotta pots, warm dry air, and active spring/summer growth; far less in low light, plastic/glazed pots, cool rooms, and winter dormancy. A fixed schedule fails because these inputs move, which is why extension guidance recommends against it (Illinois Extension).
Rough expectations by plant type (ranges, not rules)
- Succulents & cacti — soak, then fully dry; often every 2–3+ weeks indoors.
- Most foliage plants — when the top inch or two is dry; commonly every 1–2 weeks.
- Moisture-lovers (calathea, ferns) — lightly moist, never soggy; check more often.
Always confirm with the finger test.
The mistake that kills the most plants
Overwatering and underwatering both look like wilting and yellowing — so people “rescue” an overwatered plant with more water and finish it off. The decider is the soil and roots, not the leaves — see Overwatering vs Underwatering: How to Tell, and if the soil is soggy and the base smells sour, the root rot guide.
If water runs straight through (hydrophobic mix)
Very dry peat mix can repel water. Fix it by bottom-watering: set the pot in a tray of water 20–30 minutes until the surface feels damp, then drain.
The bottom line
Don’t water houseplants on a calendar — water them on a check. Soak fully, let the soil dry to the depth that plant wants, test before every watering.
More fundamentals: the Troubleshooting hub. Struggling now? See Why Are My Plant Leaves Turning Yellow?.