That is good and all, and the relay is a good tool to use for separating large loads from smaller loads but using a Motor shield is a much better option. Unless you are going to go from DC control to AC load. But most times people will use LED lights and they run off DC.This guy shows how to turn on a relay at set times
An I2C PWM Motor Shield can run up to 4 DC motors, or 2 Stepper motors, 4 Lights and many combinations. You can stack up to 32 of theses "32 stackable shields: that's 64 steppers or 128 DC motors!" These can do all that you mentioned. Like dimming lights (I have it set up to do that too.) Open and close the feeder (keep rodents out at night.) Water pump for circulation of water threw the pipes for cleaning (my video of water system).
More on my setup using this here.