Well, congratulations are in order. It only pups when things are going it's way. My usually does this after I put them out in the late spring.
Stush

Thank you! It's been in a gecko vivarium since I bought it, with Atlanta Botanical Gardens mix and a drainage layer underneath. The "soil" is constantly moist but never soggy. The lighting is exclusively CFLs.

Do you have a photo of the vicarious? Very interesting!

Here is a photo of the vivarium...

And here is a photo of the drainage layer and some of the substrate. As you can see, the substrate (ABG mix) stays quite moist, but it retains a lot of air pockets. The drainage layer always has some standing water at the bottom. The plant has been in the vivarium since early October, so more than 6 months. One factor that may or may not make a difference is that the vivarium contains thousands of springtails and numerous isopods that keep fungal growth from forming in the substrate.

That is normally too much moisture at this time of year. But what makes yours work is it is kept at a higher tempature. This is just what sans like. Good growing.
Stush

Stush,
Thank you...it makes a lot of sense that the temperature is a determining factor here. The temps in the vivarium never went below about 68 during the winter, and usually stayed at 70 F or above, even at night. Now that spring has spring, it has been warmer...mid to high 70s, which must be what triggered the pupping. By the way, pup number 2 has now emerged. :)

That is awesome!!! As Stush mentioned cold plus moisture can often cause problems with our Sans. However, you can see a lot of the commercially produced Sans in the stores are in a rich peaty mixture.........they are obviously produced in a warm area where they grow quickly and do not mind any extra moisture. Very healthy looking Sans (and vivarium!!) Keep us updated on its progress!

Thank you! I will try to keep this thread updated...I am happy to have things to post about, now that Spring is finally here. :)

As you can see in the photo, the pup will eventually collide with a leaf of the mother plant. Which is least stressful: cutting a leaf from the mother plant, or removing the pup when it is a little larger and repotting it elsehwere? Since the medium is constantly moist, will I need to leave the rhizome exposed after cutting the pup to allow it to forma callous?

Unless you want to move it somewhere I would personally leave it and the mother leaf too. They will adjust and fall into plasce. You don't want to separate it too early anyway. When do separate make a clean cut and let the pup sit out for a day or so before planting just to be safe. BTW if you do cut the leaf off (unnecessary) you can root that........it will produce solid colored offsets (no variegated edge) which are nice looking in thier own right.

Agreeing with woodnative here, it's not necessary to remove the pup. I've seen pots full of Hahnii Sans and they're rather squished, but that's "natural." No harm done to any of the plants.

Planto

Thanks to woodnative and Planto! I won't worry about moving it for now. Eventually, I will probably move it, but just because I want to. I am looking forward to growing some Jade Dwarfs without the variegation, too!

It's going strong, here's a newer pic: