My personal hard drive; currently underground

Seagate Backup Plus sealed in FoodSaver bag with desiccant; planning on digging it up in 

three years, swapping it out and testing it

Best way to seal documents

PVC pipe cache

One of the most popular methods of caching just about anything underground.

Tools for caching underground

Everything you need to get started.

How to bury your valuables and survival gear

For preppers and average citizens alike, detailed instruction written by someone with years of experience about caching underground.