I have two practices where the connections will get wet.
For areas like laws -remember, this is in a desert area- I will usually just dip the wire nuts in Scotch-Kote, aim them up (so they drain), and keep to the top of the handhole. This is a connection that can be taken apart later. Say, if the fool backs over his pole light.
For more demanding areas, say, in sump pump float connection boxes, I will slip the entire wire nut assembly into a plastic packet of a compound made for underground splices. This is a permanent connection - so you might want to make sure everything works before you do!
Code issues aside, I prefer to always use a proper handhole. Direct burial may be allowed, but those connections are then impossible to find. many will use 'bell' boxes, but I have found that even properly gasketed ones will soon fill with mud - and the ground corrodes them severely. There's never enough room to work with UF in them, and the cables are never run deep enough, either!
My 'handhole of choice' is called an N-9. It is fiberglass, about the size of a 5-gallon bucket, and has worked well for me.
