Pencil cactus care guide
Euphorbia tirucalli
Quick answer
Water your pencil cactus when the soil has dried out completely. In summer that’s typically every 11 to 17 days.
- WateringEvery 11 to 17 days · summer
Every 24 to 36 days, sometimes less often · winter - LightBright / direct light
- Climate18–28 °C (64–82 °F)
- Pet safetyToxic to cats and dogs
Not sure it’s this plant?Get the free Botanicaly app and find out with a photoWhen and how to water
- Summer · Jun–AugEvery 11 to 17 days
- Winter · Dec–FebEvery 24 to 36 days, sometimes less often
Use room-temperature water and let any excess drain. Never leave the pot sitting in standing water.
Adjust the timing for the light at the plant, the pot’s size and material, and the humidity indoors. Terracotta dries faster than glazed ceramic.
Work out your own rhythm with the watering calculator.
Light and placement
Bright / direct light
Pencil cactus needs several hours of direct sun. Turn the pot every week so it grows evenly. Place it directly in front of a south- or southwest-facing window.
Feeding
Feed your pencil cactus every 90 days while it’s actively growing. Use a cactus and succulent fertilizer, which is lower in nitrogen, at half the strength on the label, and only on soil that’s already damp.
When growth pauses, skip the fertilizer and let it rest.
Temperature & humidity
Climate18–28 °C (64–82 °F)
Humidity30–60%
During leafy growth, aim for 18–28 °C (64–82 °F). For routine indoor care, keep it above about 10 °C (50 °F) and avoid cold drafts. This is a care guideline, not an exact damage threshold. Cooler overwintering depends on the species and its rest conditions.
It does best at 30–60% humidity. It doesn’t need misting.
Toxic to pets?
Yes. Keep it out of reach.
Pet-safety information in the JungleBook uses ASPCA reference data where available. It is reference information, not veterinary advice.
Pet-safe alternatives with similar light
Common questions
How often should I water a pencil cactus?
Water your pencil cactus (Euphorbia tirucalli) when the soil has dried out completely. In summer, that’s typically every 11 to 17 days. In winter, slow down to every 24 to 36 days, sometimes less often.
How much light does a pencil cactus need?
Pencil cactus needs several hours of direct sun. Turn the pot every week so it grows evenly. Place it directly in front of a south- or southwest-facing window.
Is pencil cactus safe for cats and dogs?
Toxic to cats and dogs if chewed. Keep pencil cactus out of reach of pets, or pick a non-toxic alternative like ghost plant, old man cactus, basil, or Arabian jasmine.
Sources
- This guide follows established plant-care guidance and official ASPCA pet-safety references. How we verify our plant data →
- How we check our plant advice
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