0Astrophytum asterias
- Common name
- Star cactus
- Taxonomy
- Family: Cactaceae · Genus: Astrophytum
Still missing: plant type, native distribution, natural habitat, height / growth form, flowering period, growth & dormancy period.
Tips & experience from members
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How members water it
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How it thrives
Waterlow
Lightfull sun
Humiditylowgeneral genus data
Min. temperature8 °CJanuary
Don’t water – dry winter rest. Slight shrivelling is normal.
No feeding now.
Cool and bright, 8–15 °C: unheated room, stairwell, cold windowsill or frost-free greenhouse.
February
Don’t water – dry winter rest. Slight shrivelling is normal.
No feeding now.
Cool and bright, 8–15 °C: unheated room, stairwell, cold windowsill or frost-free greenhouse.
March
Gentle start: the first small drink once you see buds or new growth and it warms up.
First weak dose at the end of the month if it is actively growing.
The sunniest window (south or west).
Move it somewhere brighter and warmer and end wintering. Get it used to strong sun gradually.
If roots fill the pot: fresh soil, a pot 1–2 cm larger. Water sparingly for a week afterwards.
April
Deeply, but only once the soil is completely dry.
Cactus fertiliser once a month at half strength.
The sunniest window (south or west).
If roots fill the pot: fresh soil, a pot 1–2 cm larger. Water sparingly for a week afterwards.
It flowers next month – once you see buds, don’t move it any more.
May
Deeply, but only once the soil is completely dry.
Cactus fertiliser once a month at half strength.
Best outdoors: sunny balcony, terrace or garden – acclimatise it to full sun gradually.
After mid-May (last frosts) it can go outside – keep it in partial shade for the first 1–2 weeks to avoid sunburn.
It usually flowers now – don’t turn or move it, and log the bloom in your diary!
June
Deeply, but only once the soil is completely dry – more often in heatwaves, preferably in the evening.
Cactus fertiliser once a month at half strength.
Best outdoors: sunny balcony, terrace or garden – acclimatise it to full sun gradually.
It usually flowers now – don’t turn or move it, and log the bloom in your diary!
Above 35 °C, shade it at midday to prevent sunburn.
July
Deeply, but only once the soil is completely dry – more often in heatwaves, preferably in the evening.
Cactus fertiliser once a month at half strength.
Best outdoors: sunny balcony, terrace or garden – acclimatise it to full sun gradually.
It usually flowers now – don’t turn or move it, and log the bloom in your diary!
Above 35 °C, shade it at midday to prevent sunburn.
August
Deeply, but only once the soil is completely dry – more often in heatwaves, preferably in the evening.
Cactus fertiliser once a month at half strength.
Best outdoors: sunny balcony, terrace or garden – acclimatise it to full sun gradually.
It usually flowers now – don’t turn or move it, and log the bloom in your diary!
Above 35 °C, shade it at midday to prevent sunburn.
September
Deeply, but only once the soil is completely dry.
No feeding now.
Best outdoors: sunny balcony, terrace or garden – acclimatise it to full sun gradually.
Bring it in when nights drop below 13 °C. Check for pests first.
October
Taper off gradually: very little by the end of the month.
No feeding now.
The sunniest window (south or west).
Move it to its cool, bright winter spot and taper off watering. Log it with one click in the Care hub.
November · now
Don’t water – dry winter rest. Slight shrivelling is normal.
No feeding now.
Cool and bright, 8–15 °C: unheated room, stairwell, cold windowsill or frost-free greenhouse.
December
Don’t water – dry winter rest. Slight shrivelling is normal.
No feeding now.
Cool and bright, 8–15 °C: unheated room, stairwell, cold windowsill or frost-free greenhouse.
Astrophytum tip: Very prone to rot: use a mineral mix and water only during warm, sunny spells.
Star cactus – what to know
Star cactus (Astrophytum asterias) – family: Cactaceae, genus: Astrophytum. Care guidelines: light: full sun; water: low; min. 8 °C. It is not known to be toxic to cats or dogs.
All Astrophytum species in the catalog →Detailed toxicity data →
Frequently asked questions
How often should I water Star cactus?
Sparingly: let the soil dry out completely between waterings, and water even less in winter.
How much light does Star cactus need?
It needs plenty of direct sun – the sunniest window, or outdoors in summer, suits it best.
How cold can Star cactus get?
Keep it above 8 °C – it is frost-tender and needs a frost-free spot in winter.
Is Star cactus toxic to cats and dogs?
It is not known to be toxic to cats or dogs.
When does Star cactus flower?
According to the general guideline for the genus Astrophytum: Typical flowering time: May, June, July, August.
What members’ data shows
When does it really bloom?
No blooms logged yet. If yours flowers, your data will be the first!
Average watering interval
Not enough watering logs yet. Waterings logged in the care hub feed this chart.
Questions about this species
Astrophytum
Care data is for guidance only.
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