The median houseplant in this encyclopedia needs water every 10.5 days — but the average hides a 15× spread: ferns sit at ~1.5 days, cacti at ~24.5. Below is the full distribution, calculated from all 282 species in our own care database rather than repeated from a care-label consensus.
| Plant type | Species | Median interval |
|---|---|---|
| Tropical | 111 | 10.5 days |
| Succulent | 47 | 17.5 days |
| Flowering | 31 | 10.5 days |
| Herb | 27 | 3.0 days |
| Cactus | 13 | 24.5 days |
| Fern | 12 | 1.5 days |
| Palm | 9 | 10.5 days |
| Orchid | 9 | 10.5 days |
| Bromeliad | 9 | 10.5 days |
| Tree | 9 | 10.5 days |
| Carnivorous | 5 | 10.5 days |
Method, full tables and the raw dataset follow. Nothing here is estimated: every figure is countable data from the published database that also powers the encyclopedia, watering calculator and toxicity checker.
How often do houseplants need water in total?
Across all 282 species, the median interval is 10.5 days. The distribution is dominated by the fortnightly band:
| Interval | Species | Share |
|---|---|---|
| every 1-2 weeks (8-14 days) | 178 | 63% |
| every 2-4 weeks (15+ days) | 54 | 19% |
| every 1-3 days | 32 | 11% |
| about weekly (4-7 days) | 18 | 6% |
The practical takeaway: 63% of houseplants fall in the 8-14 day band, which is why "water weekly-ish" survives as folk advice. The species that break that rule are the ones that kill plants when treated like the majority — ferns and herbs dry out, cacti and succulents rot.
Which plant types need water most often?
Sorting the same data by type shows the real gaps are bigger than most care labels admit. Median intervals in this dataset:
| Type | Species | Median |
|---|---|---|
| Tropical | 111 | 10.5 days |
| Succulent | 47 | 17.5 days |
| Flowering | 31 | 10.5 days |
| Herb | 27 | 3.0 days |
| Cactus | 13 | 24.5 days |
| Fern | 12 | 1.5 days |
| Palm | 9 | 10.5 days |
| Orchid | 9 | 10.5 days |
| Bromeliad | 9 | 10.5 days |
| Tree | 9 | 10.5 days |
| Carnivorous | 5 | 10.5 days |
A fern at ~1.5 days and a cactus at ~24.5 days are not the same hobby. That ~15× difference is the single most useful number to know before buying a plant — and it is the reason our watering calculator adjusts the interval for pot size, light and season instead of printing one schedule.
What actually goes wrong with houseplants?
The database records aetiology for the same 282 species. Counting every documented problem:
| Problem | Species |
|---|---|
| Yellow leaves | 262 of 282 species |
| Brown leaf tips | 262 of 282 species |
| Root rot | 232 of 282 species |
| Pests | 232 of 282 species |
| Etiolation (leggy growth) | 53 of 282 species |
| Drooping | 29 of 282 species |
Yellow leaves and brown tips appear for 262 of 282 species each — close to universal, which means they are symptoms of ordinary care drift rather than rare disease. Root rot and pests follow. Start with our troubleshooting silo: yellow leaves, brown tips, root rot, pests.
How safe is the average houseplant for pets?
89 species are recorded as toxic to pets and 33 as non-toxic. The remaining 160 have no toxicity record in the source data — we leave those unknown rather than guess, so the pet-safe list only contains species with an explicit non-toxic record.
Browse the two lists directly: pet-safe houseplants and plants toxic to pets.
What light and humidity do these plants want?
Median ideal humidity across the 282 species is 55.0% and median ideal temperature is 21.0°C. 54 species (19%) are explicitly marked as tolerating low light, while 189 are flagged as harmed by direct sun — the ratio is why "bright, indirect" is the safe default answer for almost any new plant.
See how to judge your light and raising humidity.
Method and limitations
- Source. 282 species from plant-database.json, the same file that drives the encyclopedia. Aggregates: houseplant-care-stats.json.
- Intervals. Each entry's watering string (e.g. "every 7-10 days") is parsed to its midpoint in days, then aggregated. Ranges are genuine ranges in the source data, not computed confidence intervals.
- What this is not. It is not a survey of growers, and it is not a validation of the underlying horticultural values — it describes what this reference dataset says, so you can see the spread instead of one houseplant cliché.
- Light data caveat. "Lists direct light" is unreliable in this dataset (all 282 entries match the word "direct" somewhere in their light string), so the direct-sun figures above are reported only where entries are explicitly flagged harmful.