Hermosana watering

Hi dear members, I live in the Nord-East of Italy and I could consider myself quite a mamillaria grow-beginner therefore I'd like to ask you some questions:

-As you can see in the annexed picture I have a small Hermosana seedlings (about 3 years old I presume)repotted last spring, they grew well, I stopped to water them in the middle of September and they are placed in my cold greenhouse (Min/t 0°C) along with the other mamillarias so my question is: Could I leave them without water until next spring like the bigger one ?

Thank you in advance

Tiberio

While they are different from M.lasiacantha, I see no reason why you should treat them any differently. I've not grown hermosana from seed, but if they are 3 years old then they aren't tender young seedlings.