Sprinkler Controller Wiring (Power)
The existing wiring has the wrong color for neutral, which should be white, not green. Check it out at the upstream junction box. I recommend running a dedicated white neutral wire too.

Once you’ve done that, connect color-to-color: black for hot, white for neutral, green for safety ground.

If you’re unsure about this, consider hiring an electrician.

EDIT: should be migrated to DIY.