How often should you water a ZZ plant?
A ZZ plant keeps water stored underground and seems to need nobody. That is exactly why so many die of the opposite: too much care.
At a north-facing window, in a 16 cm plastic pot, a ZZ plant needs water every 12 days in summer and every 24 in winter. Before watering, make sure the soil has dried out well; if in doubt, give it a few more days.
Why can a ZZ plant go so long without water?
The ZZ plant (Zamioculcas zamiifolia) is an African plant that grows from thick rhizomes hidden in the soil. Many guides describe those rhizomes as water stores, and university extension services agree on the essentials: it tolerates long dry spells and a fair amount of neglect. The flip side is less well known. According to the University of Connecticut extension, overwatering is practically the only thing that kills it.
So the right gap between waterings depends mostly on how quickly the soil dries in your pot, and three things change that:
- Light. With more light a ZZ plant works harder and drinks more. In a dark corner it uses almost nothing.
- The pot. A large pot holds moisture for much longer. Terracotta dries fast; plastic and glazed ceramic hang on to water.
- The season. Growth slows in winter and the same watering lasts a good deal longer.
Here are the numbers for one ZZ plant, in one pot, in four spots around a home:
| Where it lives | In July | In January |
|---|---|---|
| South- or west-facing window | 7 days | 13 days |
| East-facing window | 8 days | 15 days |
| North-facing window | 12 days | 24 days |
| Hallway or corner with no window | 18 days | 34 days |
The pot counts too. At the same north-facing window in July, a 25 cm plastic pot lets a ZZ plant wait 19 days, while a 16 cm terracotta pot gives it 9.
Do you water a ZZ plant in low light the same way?
No. The ZZ plant is famous for coping with dim rooms: the University of Florida notes it keeps producing new leaves in very little light, which is why it turns up in offices and hallways. But it grows far more slowly there, and a slow-growing plant barely drinks. In a dark spot the real danger is soil that stays wet for weeks. If your home is short on light, see the plants that cope best with low light, and water by the soil, not by habit. Strong direct sun doesn’t suit it either: bright, filtered light is what the guides prefer.
How do you know when a ZZ plant needs water?
The finger test works, but go deeper than with most plants. If the soil is dry halfway down the pot, or nearly all the way, it’s time to water. If there’s still moisture lower down, wait. Sources don’t fully agree on how dry is dry enough: some say let it dry slightly between waterings, others say wait until it is completely dry. With a plant this tolerant of drought, the dry side is the safer one.
Other helpers:
- The weight of the pot. Dry, it lifts with almost no effort; still wet, you’ll feel it.
- A wooden skewer. Push it to the bottom and pull it out: if damp soil clings to it, not yet.
- The leaves. Unlike a pothos, a ZZ plant doesn’t flop overnight when thirsty, so don’t wait for it to ask. By the time the leaflets wrinkle or lose their shine, it has been dry for a long while.
What’s the right way to water a ZZ plant?
- Water thoroughly, until it runs from the drainage hole, so all the soil gets wet.
- Empty the saucer soon after. A ZZ plant should never sit in water.
- Use a pot with a hole and a free-draining mix. A light compost with bark or perlite lets the roots breathe.
- Skip the little and often. Frequent small splashes keep the soil permanently damp, which is exactly what this plant can do without.
How do you spot an overwatered ZZ plant?
The most cited signs are yellow leaves, soft stems at soil level and rhizomes that turn mushy and rot. If you see this, stop watering and let the soil dry out completely. If the stems are already soft, lift the plant out, cut away the rotten parts of the rhizomes and repot into fresh, dry compost. Dark markings on the stems are not a worry in themselves: Clemson’s extension service says they are normal for this plant.
Underwatering is far rarer, and a good soak sorts it out.
At a glance
| Situation | What to do |
|---|---|
| Soil still damp halfway down | Wait |
| Soil dry almost to the bottom | Water thoroughly and empty the saucer |
| Dark spot or winter | Space waterings out even more |
| Yellow leaves and soft stems | Stop watering and check the rhizomes |
| Wrinkled leaflets, soil dry for ages | Give it a good drink |
Quick questions
Can I water a ZZ plant from below? Yes: stand the pot in a basin of water until the soil is damp, then let it drain well. Don’t forget it there.
Should I mist the leaves? There’s no need. A ZZ plant doesn’t ask for high humidity; the soil is what matters.
Is tap water fine? Yes, at room temperature.
How long can it go without water? Far longer than most houseplants, thanks to the rhizomes, but there’s no fixed limit: it depends on light and pot. The table above gives the measure for each spot.
Who remembers a plant that barely asks for anything?
With a ZZ plant, the hard part isn’t remembering to water: it’s remembering not to, and then remembering again weeks later. Verdejar does the sums with your light, your pot and the month, and nudges you only when it’s needed. See also the ZZ plant page.
Sources: University of Connecticut Extension · Iowa State University Extension · Clemson Home & Garden Information Center · UF/IFAS Extension. The days between waterings come from the Verdejar watering engine.