Mammillaria bella and sheldonii

These are great photos of very well grown plants!

I think that M. bella, or nunezii ssp. bella is a very lovely plant, and yours must be quite an old plant to have grown as tall as it is. The plants from the south west of Mexico, like M. nunezii and, of course M. guerreronis, need more warmth in winter than some species, but they are well worth the extra heat.

Chris43 wrote:

...  yours must be quite an old plant to have grown as tall as it is.

Indeed, they are not that young :
- I got M. bella in 2001 and that time the plant was ~5
- M. sheldonii is exactly 15

Chris43 wrote:

The plants from the south west of Mexico, like M. nunezii and, of course M. guerreronis, need more warmth in winter than some species, but they are well worth the extra heat.

I keep my plants out-doors until temperature drops below zero - sometimes until November.
Then I move them to my cellar where temperature varies from +15 to +5.
It happened once when it was -5 for one night but none of my cacti suffered.

Do you think I should keep them in a warmer place?

Usually a short drop in temperature won't harm, it is more long periods of cold that does for even well dried out plants. If it works for you, don't change it, as clearly the plants are fine.

high temperatures in Poland (above 30 C) favours flowers

I have a little doubt about the identity of the M. bella. To me this plant looks more like M. michoacana. Also, the photos in Pilbeams books (his 1981 and his 1999 book) show a somewhat different plant than the one shown by Przemyslaw.
My own plants of M. bella (13 years old) conform quite well to the plants shown in the Pilbeam books, they are still globular despite their age.
Attached are a few habitat photos of M. bella from a location south of Taxco (ML 27/28).

Wolter ten Hoeve.