Pincushion cactus care guide
Mammillaria
Also known as: Mammillaria elongata, Old lady cactus, Mammillaria zeilmanniana
Pets and children
Caution advised
The hooked spines catch skin, fur and mouths and can injure; no reliable toxicity is reported, but keep it out of reach and consult a veterinarian or doctor if spines lodge or it is eaten.
How often to water Pincushion cactus
- Spring–Summer (Mar–Sep)
- Every 10 days
- A summer grower that slows in the Japanese midsummer: water well two or three days after the soil dries through, and more sparingly in the evening in July and August, as a guide.
- Autumn (Oct–Nov)
- Every 14 days
- It grows again as it cools: water about a week after the soil dries, as a guide.
- Winter (Dec–Feb)
- Every month
- Dormant: keep it nearly dry with a light watering about once a month on a warm morning, as a guide.
Light and placement for Pincushion cactus
A sunny, airy spot all year, as a guide: too little light stretches the body and stops the spring flowers, midsummer wants light shade from afternoon sun and good airflow, and the white-haired kinds want the most sun.
Overwintering Pincushion cactus
Overwintering guide: 3°C (37°F) or above
Kept dry it generally takes about 3°C: as a guide, move it to a sunny window indoors when nights dip below 5°C and rest it dry, since a proper winter chill brings the ring of spring flowers.
Fertilizing and repotting Pincushion cactus
Fertilizer
Very little: diluted liquid fertilizer about once a month from April to September and none in fall or winter, as extra feed makes it leggy and cuts flowering.
When to repot
Spring–Summer (Mar–Sep)
Common problems with Pincushion cactus
- Watered in winter, the roots rot and the base turns brown and soft.
- Short of light the tip stretches thin and the white hair thins out.
- Water pools between clustered heads and they rot.
Tips for growing Pincushion cactus
- The spring flowers form a ring near the crown, so the dry winter rest matters.
- Divide clumps in spring every few years to keep air moving between the heads.
- The spines are fine, so handle it with thick gloves or a rolled paper.
These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.
Keep your plant log going
Greenery is a free app that keeps your plant care going, with watering reminders and photo records. Available on iOS and Android.
