Question
We want to move our sprinkler system control box from the basement to the garage. To do this, we need a the 7-strand wire coming out of the box to be longer. The wire is Baron 18AWG - can we splice that with some 7-strand Rainbird wire, or other sprinkler system wire? Do we need special connectors? Thank you.

Answer
No special wire is needed. You can use any type of 18GA wire. If your wire is going to be exposed to sunlight or buried then you need an underground rated wire. All "irrigation" specific wire is underground rated. So the Rainbird would be fine.
The indoor connections can be just plain wire nuts. I'd suggest installing a small electrical box in the basement and make all the connections in it. It protects the wires and anyone walking by. It's only 24 volts, but it feel like a bee sting.

Matt