Turbinicarpus POLASKII, La Bonita

Turbinicarpus POLASKII, La Bonita - Polasky's turbinicarpus, Polaski's turbinicarpus, Turbinicarpus SCHMIEDICKEANUS 'SCHWARZII'.

Turbinicarpus is a genus of miniature plants in the family Cactaceae, naturally associated with arid regions of Mexico, especially limestone and gypsum habitats in the northeastern and central parts of the country. These are small, slow-growing cacti with globose, flattened, or short-cylindrical stems, pronounced tubercles, and a well-developed taproot.

In many turbinicarpuses, the body is partially submerged in the soil or camouflaged among stones, and the spines can be thin, papery, curved, feathery, or poorly developed. This appearance helps the plants endure bright sun, dry air, poor mineral soils, and sharp diurnal temperature fluctuations in their natural habitats.

Flowers appear at the top of the stem, usually solitary, funnel-shaped, white, cream, pinkish, or with a more saturated central stripe on the petals. The fruits are small, dehiscent when mature, with tiny dark seeds. In cultivation, turbinicarpuses are valued as compact collector cacti, but require a very careful watering regime and a mineral, quick-drying substrate.

Polasky's turbinicarpus is the collection name of a miniature Mexican cactus that forms a solitary or rarely with age weakly clustering stem of small size, greenish, grayish-green, or bluish-green, with rounded tubercles and areoles at their apexes. The spines are usually few, curved, light or brownish, may appear papery over time, and emphasize the plant's natural camouflage among mineral debris.

Flowering occurs during the warm, bright period of growth. The flowers open at the top of the stem, usually white or pinkish-white, with a delicate central stripe and yellow anthers. Due to its small size, dense shape, and expressive flowering, this turbinicarpus is well suited for mineral collections, small pots, and bright cactus display cases.

Turbinicarpus seeds are small and dark.

Sowing is carried out on the surface or with the thinnest dusting of sifted sand or fine mineral fraction. The substrate is pre-moistened, the seeds are distributed over the surface, then the sowing is carefully sprayed from a spray bottle with a weak solution of potassium permanganate or biofungicide with the addition of a growth stimulant: SUPERthrive, HB-101, Aminozol, Epin, or Zircon, placed in a mini-greenhouse, and germinated under bright diffused lighting, a temperature of about 22-28 °C (72-82 °F), and high but not stagnant air humidity. Sowings are kept closed until seedlings emerge, then short ventilations begin, gradually increasing air access. The surface of the substrate must remain slightly moist, without waterlogging, drying out of the top layer, or overheating under direct sunlight.

Under favorable conditions, the first sprouts may appear in about 5-10 days; the bulk usually germinates within 2-3 weeks, while individual seeds can take up to 4-6 weeks. Turbinicarpus seedlings develop slowly, so pricking out is performed not on a calendar schedule, but after noticeable strengthening of the little cacti and the appearance of the first spines. Young plants are transplanted very carefully, with small tools, into a loose mineral substrate and initially protected from harsh sun.

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For turbinicarpus, the brightest possible location with plenty of direct or very bright diffused light is chosen. Southern, southeastern, and southwestern windows, a bright greenhouse, or a shelf with strong supplemental lighting are best suited. Young plants and specimens after repotting are accustomed to direct sunlight gradually to avoid burns on the stem.

During the period of active growth, a comfortable temperature is 22-30 °C (72-86 °F) with good air movement. In summer, the plant tolerates heat better with a dry root neck, a mineral substrate, and ventilation. In winter, a dry, cool wintering is needed, usually around 5-12 °C (41-54 °F), with complete or almost complete cessation of watering. Prolonged cold dampness is more dangerous for the root and root collar than a short-term drop in temperature itself.

Watering is carried out only after the substrate has completely dried out. In spring and summer, the plant is watered rarely but thoroughly, then the pot is allowed to dry out completely. In overcast, cool weather, watering is postponed. In autumn, watering is gradually reduced; in winter, it is kept dry. Water must not linger at the base of the stem, and excess moisture from the drip tray is removed immediately.

For planting, a very loose mineral substrate with a high content of perlite, coarse sand, pumice, lava grit, zeolite, or other mineral fractions is used. Organic matter should be minimal. Due to the taproot, it is better to choose a small but sufficiently deep pot with large drainage holes and a layer of drainage.

Fertilizer is applied only during the period of active growth, infrequently and in weak concentration, preferably with a cactus fertilizer with moderate nitrogen content. Repotting is not carried out annually, but as the pot is filled, with mandatory drying after repotting before the first watering. Root damage and planting in a moist substrate often lead to rotting.