Gymnocalycium horstii (Spider Cactus)

Botanical & Common Names
- Botanical name: Gymnocalycium horstii
- Common names: Spider Cactus

Background & Origin
Gymnocalycium horstii, commonly called the Spider Cactus, is a globular cactus native to high-altitude rocky regions of South America. It features 5–6 ribs with clusters of curved spines that bend back toward its body, giving it its distinctive “spider” look. In the wild, it thrives on exposed rocky outcrops and, under the right conditions, produces small, charming flowers, making it a striking and compact addition to any cactus collection.

Care Level
- Care level: Easy
- Suitable for beginners: Yes!

What It Loves
- Bright warm spot
- Letting the compost dry out

What It Dislikes
- Overwatering or sitting in soggy soil
- Dark spots will cause legginess

Best Rooms for This Plant
- Bedroom
- Living room
- Office
- Conservatory

Growth Potential
- Typical height indoors: 10 - 20 m in height
- Typical spread: Up to 10- 20cm wide
- Growth rate: Slow growing
- Pruning required: No

Is This Plant Right for You?
This plant is a great choice if you:
- Love unique, conversation-starting plants
- Want a compact plant for small spaces

Light
- Best light: Bright warm spot with some direct sunlight
- Avoid: dark shady spot

Watering
- Frequency: Water when soil is completely dry,
- Seasonal note: Reduce watering in winter when growth slows to almost none.

Humidity
- Prefers: No humidity
- Extra humidity helpful?: These plants are native to arid conditions and do not require humidity.

Feeding
- Feed with: A balanced houseplant fertiliser
- Frequency: Once or twice during growing season during spring and summer. No feeding is needed during autumn and winter.

Toxicity
- Pet safe: Yes
- Notes: Keep out of reach of pets and small children to avoid damage and spikes

Repotting
- How often: Once a year
- Signs it’s needed: Roots growing out of the drainage holes, slower growth, or soil drying very quickly. Choose a pot only slightly larger than the current one to avoid overwatering.