One more question tonight. Our winters are usually pretty cold. Down to 0c or even less especially at night. My house is heated by several space heaters, no central heat. So usually my house is around 18 or 19 c.
For Mammilaria is this a good temp to have them in or should I move them to a cooler room for the winter. ? They would continue to get lots of sun where they are now. In the other room lighting would be next to nil.
So would they do better in next to no light as long as kept cool (cold) and dry. Or where they are now and be cool and in that case should they be watered a wee bit during the winter.
Thanks for any help in keeping my mammalaria babies growing onward. I do appreciate it.
Wendy

Hi Wendy,
Most cacti like a winter rest. In the UK where I live, I tend to stop watering by mid October, sometimes earlier if its not too warm or bright - my plants are in a greenhouse. I set my heating to a minimum of 6C which is fine for most Mamms (and most other cacti apart from some from Brazil and the Caribbean).

Once they have dried off, then they don't grow and so the need for light is greatly reduced. They probably therefore should be OK without much light if they have become truly dormant. But the problem that I would forsee (remember I haven't tried this myself) is in the Spring. Usually the extra warmth and light starts growth, even if no water has yet been given. Flowers often start to form well before Spring comes. You'd need to watch carefully for any signs of growth, and move them as soon as that happens into a much lighter area. But be careful, because too much light after a period of lower light levels coud just create a bit of scorch, especially on new growth. So I would probably give some light shading for a week or two and then allow full light after that. And if its nice and warm, then start watering.

I have heard of some people who take their plants down to their basements for the winter, but a few I know also use artificial lights down their for 12 hrs a day - to mimic good natural light as this helps flower production.

Otherwise, you can just keep them in the warmer and lighter area, in which case I would give a little water, maybe every month to stop excessive shrivelling, but not enough to start them into real premature growth.

I'm sorry that I can't be more certain about what to suggest, but I hope it helps you decide.

Well Chris you have been a lot of help to me here. You answered my questions thoroughly and I appreciate it. A long time ago I had a Mamm boscana, I really liked that little plant but I lost it. For some reason it died on me. So I tend to check all my plants daily and sometimes twice a day. So if I put them in the other room I will be checking on them, to be sure.
Thanks a million for your advice and help
Wendy