Weingartia ARENACEA

Weingartia ARENACEA - Sand weingartia, Rebutia arenacea, Rebutia GLOMERISETA, Sulcorebutia MUSCHII.

Weingartia is a genus of cacti in the cactus family (Cactaceae), comprising about 10 species growing in the mountainous regions of Bolivia and Argentina.

The genus is represented by small globular or flattened cacti with a dense covering of spines. The stem is solitary or forms compact clumps; the surface can be glaucous-green or grayish-green. The ribs are usually low, divided into tubercles; the areoles bear slender straight or slightly curved spines.

Flowering occurs in spring or early summer. The flowers are funnel-shaped, yellow or orange, often with glossy petals, opening during the day. The fruits are small, globose, dry, dehiscing longitudinally. Seeds are dark, small, round-oval, with a rough surface.

Sand weingartia is a low-growing cactus with a solitary globose stem reaching 5-7 cm (2.0-2.8 in) in diameter. The surface is matte, dark green, with distinct tubercles. The spines are slender, light, up to 1 cm (0.4 in) long, closely appressed, and evenly cover the surface.

It blooms in late spring. Flowers are bright yellow, up to 4 cm (1.6 in) in diameter, with glossy petals and a short tube. They are located along the top of the stem. Fruits are small, dry, brownish, dehiscing upon ripening. Seeds are black, rounded, with a rough coat.

Seeds do not require stratification or scarification before sowing; they are pre-soaked for 1-1.5 days in a weak solution of potassium permanganate. Then they are sown on the surface without burying into a well-steamed loose mixture of equal parts coarse river sand, peat, and turf soil. The mixture is moistened with a spray bottle and covered with glass or film. The most favorable temperature for seed germination is 25-35 °C (77-95 °F). Germination takes place in light, but not in direct sun. Seedlings need ventilation. Overwatering and drying out of sowings must be avoided.

The first seedlings appear in 7-21 days. Within 1-2 weeks, as a rule, all viable seeds germinate. In individual cases, germination may drag on up to 30 days. Sprouted seeds can be helped with a needle to free themselves from the seed coat or direct a rootlet sticking out to the side into a hole made in the soil.

About a month after germination, upon the appearance of the first spines, as well as if the soil surface becomes overgrown with algae, it is necessary to prick out the seedlings into a new soil mixture. The airing time should be gradually increased and the container lid can even be left permanently slightly open.

After 2-3 months, the lid can be completely removed, avoiding complete and prolonged drying out of the soil clump until the seedlings gain the necessary biomass.

Transition to adult care becomes possible and justified after the plants reach 1-1.5 cm (0.4-0.6 in) in diameter. Frequent pricking out into new pots and soil mixture (once every 2-3 months) noticeably accelerates plant development.

After 2 years, it is entirely possible to grow plants 3-4 cm (1.2-1.6 in) in diameter, some of which will certainly bloom in the third year.

© Greeniverse. All rights reserved.

Growing weingartia in city apartment conditions is recommended to start from seeds in order to gradually accustom plants to a stable home microclimate. Such an approach is considered the most reliable, since replicating the mountain climate of Bolivia is impractical. Bright lighting and fresh air supply are required, although in spring shading from direct sun rays is desirable to avoid burns.

During the warm season, a temperature of 20-28 °C (68-82 °F) is maintained; in winter, keeping at 6-8 °C (43-46 °F) in a dry room is preferred. Watering is carried out cautiously, after complete drying out of the substrate, with soft water having a neutral or slightly acidic reaction. Overwatering is not permitted.

Deep pots with a well-drained substrate consisting of leaf mold and sand are used. The root system of the plant is elongated and turnip-like, so sufficient pot depth is ensured. Repotting is carried out as necessary in spring; drainage is mandatory.

During the period of active growth, mineral fertilizers with increased potassium content are applied once every 3-4 weeks. Nitrogen fertilizers are not used, as they negatively affect plant development. Feeding ceases in autumn and is not resumed until spring.

Shaping and pruning are not required. Reproduction is carried out predominantly by seeds. Cultivation does not cause difficulties and can be successfully maintained subject to basic conditions. Weingartias are recommended to novice collectors as undemanding cacti responsive to care.