Making a garden herp friendly means you need to make these available:
- Water
- Food
- Hiding places
Water and food are pretty easy, especially for snakes. Put up a bird bath and bird feeder. Birds drop a lot of seed on the ground, which attracts rodents.
For hiding places, a wood pile works. If you don't have a reason to keep firewood around, a small rock garden surrounded by 6-8" high ground-cover plants will work.