Sphagnum moss is one of the most versatile products used by tortoise keepers, whether for dry or humid habitat species. 
A medium that is fantastic at holding water, it can be mixed through substrates for high humidity species, used as a humid hide substrate and fantastic to put around growing plants to keep them hydrated.
Known for it's anti-bacterial and anti-fungal properties, it is a great addition to high humidity area's. Hydration is massively important to all tortoise species and this is ideal to help keepers keep those area's with high humidity but with minimal effort. Spraying with water just once a day is plenty enough to keep it moist. 
This product will come to you dried. Simply soak in some water until soft. Squeeze out excess water and add to the enclosure!
Approximate amount shown in the picture with the £1 coin for size reference is just 1 litre. A little goes a very long way with this product, 1 litre will easily make a humid hide for most small-medium species. 
It is 100% organic and is safe to be eaten if the tortoise decides to take a nibble!