Photo: Lemaire, Charles Antoine / Public domain

Bishop's Cap Cactus Care

Astrophytum myriostigma · Cactaceae

🐾 Pet-safe 🎯 Moderate ☀️ Bright with some direct sun 💧 Every 14–32 days

🕮 7 min read 🕓 Last reviewed: 2026-08-23

Care at a glance

Watering

Every 14–32 days

Light

Bright with some direct sun

Temperature

8–35 °C (46–95 °F)

Humidity

Low

Soil

gritty, fast-draining cactus/succulent mix

Difficulty

Moderate

Mature size

10–30 cm (4–12 in)

Pet safety

Pet-safe

Care effort Medium

The short version

A little attention keeps it happy.
Give it Bright with some direct sun.
Water every 14–32 days.
Safe around cats and dogs.

The Bishop's Cap Cactus (Astrophytum myriostigma) is a popular houseplant from the Cactaceae family, native to Northern Mexico. It is rated Moderate to grow and typically reaches 10–30 cm indoors. Here is everything you need to keep it healthy — watering, light, humidity, feeding, propagation, and pet safety. It is a Slow grower, putting on most of its growth in the warm, bright months of spring and summer.

Also known asAstrophytum myriostigma鸞鳳玉鸾凤玉Gorro de obispoBonnet d'évêque

📋Quick facts

Growth rate	Slow
Mature size	10–30 cm (4–12 in)
Native region	Northern Mexico
Plant family	Cactaceae
Toxicity	Non-toxic
Air-purifying	No
Ideal for	homes with pets, frequent travellers, a pop of colour

⚖️Pros & cons

Pros

Non-toxic to cats and dogs
Very drought-tolerant — forgives forgetful watering
Flowers indoors
Compact — fits a desk or shelf

Cons

Needs a bright, sunny spot
Slow grower — patience required

💧Watering

Water your Bishop's Cap Cactus roughly every 14–32 days, letting the top few centimetres of soil dry out between waterings. Always empty the saucer so the roots never sit in water — overwatering is the most common way this plant is lost.

Not sure when to water? Push a finger 2–3 cm into the soil and water only when it feels dry at that depth — a cheap moisture meter or the weight of the pot works too. Water thoroughly until it runs from the drainage holes, then tip away anything left in the saucer. Soft, yellowing lower leaves usually mean too much water; crispy, curling leaves usually mean too little. Always ease off in the darker months, when the plant drinks far less.

Never forget to water

Adds a repeating event to Google Calendar every 23 days.

📅 Add a watering reminder

☀️Light & placement

The Bishop's Cap Cactus wants bright light with a few hours of direct sun, such as a south- or west-facing window.

A south- or west-facing window is best, where it soaks up a few hours of direct sun a day. If it has been in a dim spot, introduce stronger sun gradually over a week or two to avoid scorching.

🌡️Temperature & humidity

Keep it between 8–35 °C and away from cold draughts and heating vents. It prefers Low humidity; if your air is dry, group it with other plants or use a humidifier.

🪴Soil & feeding

Plant it in gritty, fast-draining cactus/succulent mix. Feed with a light succulent feed once or twice in the growing season, and stop feeding in autumn and winter when growth slows.

🗓️Season-by-season care

Season	Watering	What to do
Spring (Mar–May)	Resume regular watering as growth restarts.	The main growing season begins — start feeding again, repot if it is pot-bound, and take cuttings now for the best success.
Summer (Jun–Aug)	This is the thirstiest season; check the soil more often.	Keep feeding on schedule, watch for pests in the warmth, and shield the leaves from scorching midday glass. Higher humidity is welcome.
Autumn (Sep–Nov)	Let the soil dry a little longer between waterings.	Taper off feeding as growth slows, and move the plant away from cold windows and doorways before the first chills.
Winter (Dec–Feb)	Water sparingly — overwatering now is the number-one killer.	Stop feeding, give it the brightest spot you have, and keep it away from radiators, heat vents, and cold draughts.

🪟Repotting

Repot roughly every 2–3 years, ideally in spring as growth picks up. Move up just one pot size (2–3 cm wider) with drainage holes — too big a pot holds water and invites root rot. Signs it is time: roots creeping from the drainage holes or circling the surface, water running straight through, or growth that has stalled. In the years you do not repot, scrape off and replace the top few centimetres of soil.

✂️How to propagate, step by step

Spring and early summer, during active growth, give the best success. Here is how to do it, step by step:

seed

Sow fresh seed onto the surface of moist, fine seed-starting mix.
Cover lightly only if the seed needs darkness; most need warmth of 20–25 °C.
Keep humid under a clear cover in bright, indirect light.
Germination ranges from days to months depending on the species — be patient.
Prick seedlings out into their own small pots once they have a few true leaves.

🔬Classification

Plant type	Cactus
Genus	Astrophytum
Family	Cactaceae · Cactaceae
Native to	Northern Mexico

🩺Common problems

Symptom	Likely cause	What to do
Soft, mushy base (root rot)	Waterlogged soil	Repot into fresh dry mix, trim rotten roots, and water less.
Pests (mites, mealybugs)	Dry conditions or a new infected plant	Wipe the leaves, rinse, and treat with insecticidal soap or neem.
Brown spots on leaves	Inconsistent watering, cold draughts, or fungal issues	Water evenly, keep it warm, and remove badly affected leaves.

🩺 Plant Doctor →

🐛Pests & prevention

The usual indoor pests are spider mites (fine webbing, speckled leaves), mealybugs (white cotton-wool tufts), scale (small brown bumps), and fungus gnats (tiny flies from soggy soil). Inspect any new plant before it joins the others, wipe the leaves now and then, and let the topsoil dry to keep gnats away. At the first sign, isolate the plant, wipe or rinse off what you can, and treat with insecticidal soap or neem oil every week until it is clear.

🐾Is it safe for pets?

Good news for pet owners: the Bishop's Cap Cactus is considered non-toxic to both cats and dogs by the ASPCA. It is one of the safer choices for homes with animals, though eating any plant can still cause mild stomach upset.

Toxicity information is a general guide based on ASPCA data. If your pet or child may have eaten any part of a plant, contact a vet or poison control right away.