Depends on the species. Do you know which one's you have?
The common name "Spike Moss" is used for most species in the Genus and is of no help in identifying a particular one.
Selaginella species habitats range from bogs and swamps to deserts and from tropical rain forests to artic tundra.
Would help if you could post a photo.
Rb

Alright, here I found a picture of one on the net.

{{gwi:597790}}I think it's Selaginella kraussiana

I believe you are right. S. kraussiana thrives in a moist, shady location and seems to prefer acidic soil. A S African native that is hardy here in Z7 and spreads fairly rapidly to form large cushion mats in undisturbed areas. There are 2 very attractive cultivars with golden foliage, 'Aurea' & 'Gold Tips', plus a green one, 'Brownii', that forms large clumps. For some reason, the golden forms seem to thrive more readily here than the ones's with green foliage.
Good luck with yours!
Rb

Hi
As RB pointed out there are hundreds of specie of these and to make it more complicated they change color and habit by weather conditions. i bought an unidentified specie at a local Walmart which has turned pink with the arrival of cool weather. Clipped some and put into a terrarium and it turned brilliant green lol
they seem very adaptable though they resent the florida heat. One of my favorites is S.uncinta which can be turned a brilliant blue by lowering the acidity.
I've killed a few of these but they seem to like bright indirct light ,high humidity and lots of water.
Keep an eye out for some of the vining types as well as the red ,yellow and changeable colored ones. Really fantastic!!
gary