Mammillaria guelzowiana - 10 seeds

Mammillaria guelzowiana is a perennial plant that grows fleshy, globose, at first solitary and then forming groups. The stems have a spherical, apically depressed, about 7 inches tall and 4-10 inches in diameter. Tubercules are conical and cylindrical. They do not contain latex. The plant has 1-6 thin central spines, needle shaped, yellowish red, 8 to 25 millimeters long. The 60-80 radial spines are long and twisted, about 15 mm long. The bell-shaped flowers are purple, more or less bright, up to 4 inches long and can reach 7 inches in diameter. The fruits are almost spherical, bright red or yellowish white, about 8 mm in length.

HOW TO GROW?

It is one of the more difficult species to grow long enough to produce clumps, but if grown correctly, it will reward the grower with generous displays of purple flowers; plants should be allowed to become crowded in their pot. Keep in shallow pots.
Need regular water but do not water again until dry as it is specially sensitive to over watering. Also, it is a species that is dormant in the winter and require very little water (maybe even none) during the cold months. 
 Light frost protection required. Minimum of 5ºC for safe growing (but hardy up to -5°C or less.) 
 High levels of light are needed to flower and for good spine development. Can be sunburned if moved from shade/greenhouse into full sun too quickly. During the spring it may be able to take full sun until the heat arrives at the end of spring. In an area that has hot afternoon sun, it may be able to take full morning sun, but requires afternoon shade or afternoon light shade. 
Leave seeds or offsets that appear at the base attached to form a cluster, or wait until they are 1/3 the size of the parent and then detach and plant.