Thimble Cactus

Also commonly known as “Thimble Cactus” or “Powder Tassel,” this is a low-maintenance, tussock cactus that does not usually exceed 3 inches in height, grows in clusters has dark green conical tubers. The areolas have white wool and are round; these can include up to 50 intertwined radial white spines and 1 to 7 thicker central reddish spines. Some varieties of this plant are better known; they are smaller and have white central spines with a brown tip, with fewer radial spines, partly brown, and without central spines. These unique cacti are short in height, but they add a peculiar beauty and color to our garden because they grow in groups.

Thimble Cactus-SC
A picture of Thimble Cactus @thedangergarden


Due to their small dimensions, the most common is to grow them in pots and planters. These are slow-growing, fast-spreading plants and are an excellent addition to rock and cactus gardens. Since it grows in clusters, it is also well suited to fairy gardens. Flowering in this species does not occur until the specimen is not at least three years old. The fruit is orange. It has small yellow or cream flowers.

While the usual flowering time for these succulents is late spring or early summer, in some cases, we can see beautiful and striking yellow flowers in winter as well. For this flowering to be best, allow the plants to enjoy a cooling period in winter. We must stop irrigation entirely during this time. One of the many characteristics that differentiate this cactus from others is that Mammillaria has tubers from which the flowers emerge at the time of flowering.

Thimble Cactus-Soil Required-SC

Soil Required

Thimble Cactus requires porous soil; a particular substrate for cacti may be ideal. It can also grow well in a mixture of cactus soil and rich, fast-draining ordinary soil with a pH range between 6.1 and 6.5. Some species of these types of plants require sandier soil for potting cacti or succulents for best results. When grown in a pot, the earth can be a mixture, in equal parts, of coarse sand, garden soil, and leaf mulch or also a commercial substrate for cacti.

Thimble Cactus-Cultivation-SC


In indoor cultivation, it produces a group of small round offsets around the mother plant. These are densely covered with silky white hair, the body of the plant is generally green/blue. Since short white spines densely cover the globes, this looks like a speck of dust around the mother plant. If this cactus is kept in the right conditions, it grows slowly but steadily until it reaches its mature size. A slow-growing, mature Mammillaria cactus can grow to about 5 inches tall and 4 inches in diameter. To obtain the best results in its growth, provide the plants with good airflow; for this, we will find that a window sill with lots of sunlight is an optimal environment conducive to the cactus to thrive.

Thimble Cactus-Weather Conditions-SC
Sunshine Bloom:IG@iowasian

Weather Conditions

The Mammillaria gracilis cactus prefers full sun exposure; however, we must bear in mind that although most Mammillaria species prefer intense light, some cannot survive more than four hours of direct sunlight. It is also preferable to keep it in high temperatures. This little cactus grows well in temperatures between 70 and 80 ° F and becomes dormant in winter.

When temperatures drop to between 60 ° and 65 ° F, the plant will give flowers. The winter temperature should not drop below 41ºF, and although they could withstand a weak frost; It is convenient to rest at about 50ºF. Thanks to the fact that this cactus can withstand the cold well as long as it is dry, we can keep our “Thimble Cactus” as indoor plants during the winter. When summer returns, we can move our cactus outside again to receive more light and air and begin its spring flowering season. Since “Thimble Cactus” plants are not resistant to intense cold, we must offer them plenty of sun on a window sill protected from the elements.

Thimble Cactus-Watering-SC
Watering image: IG@vtdiscthrower


The watering of our “Thimble Cactus” will depend on the season in which we are. In summer we can water it regularly every other day, in spring, only about twice a week. In this measure, they will decrease in autumn until almost eliminating all irrigation in winter, this being approximately one time a month at most if they are grown outdoors. Something essential for this cactus’ healthy watering is to wait until the soil has completely dried before watering again to avoid drowning it. We must not expose our plant to prolonged humidity or let it rest in the water for extended periods, so we must be attentive to any dish under the pots to avoid any waterlogging.

Thimble Cactus-Fertilizers- potted in beautiful marble pots-SC
Source: IG@peacockandcompany


The “Thimble cactus” does not require a specific pruning or fertilizer for its growth. However, we can fertilize it with commercial cactus compost in its growing periods to grow more healthily, and its flowering season is abundant. The pot transplant is carried out at the beginning of spring. Its cleaning and maintenance are simple. We must monitor any rot that appears and cut it quickly before it spreads. In case the plant is overcrowded, a pot transplant is necessary; this is an excellent opportunity to remove all the rotten or dead roots that our plant may have.

Thimble Cactus-Reproduction-SC


It is possible to multiply our “Thimble Cactus” by rooting the lateral suckers or seeds sown in spring in a sandy and slightly humid substrate. To reproduce it by cutting, we must carefully remove the suckers and dry them for a couple of days. We will know that they will be ready to plant when a callus forms on the cut surface. At that time, we take a new pot filled with a mixture of substrate for cacti and garden soil; and there we will place our cuttings. It is imperative to keep them in a warm and dry place where they receive enough light.


These plants are susceptible to excess moisture; this produces a rot in their roots that can spread to the stems and kill it. In case of excessive dryness, you will also be in danger of the spider mite attack. When grown as a houseplant, it often contracts bacterial diseases caused by excessive watering. That is why it is essential to follow a strict irrigation schedule. The “Thimble Cactus” is also susceptible to attack by some pests such as mosquitoes or mites, but nothing is not resolved with insecticide or rubbing alcohol carefully.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.