What is a Hydroponic System?
A system were you grow plants through the use of water and nutrients instead of soil. This means that you in some way need to make sure that the plants are given the water with nutrients off and on in such a fashion that the plants get all they need without rotting from too much water.
What kind of pump do I need?
This of course depends on your setup. See more at hydroponics-at-home.
If no sun is available, try out some LEDs. LED Grow Lights