Arduino self irrigation moisturising system

hi guys,
my name is lucky,
I am a 12 year old kid
and am
But I am new to Arduino Programming and circuito.io,
and am a big fan of @discobot
so can you help me out with the components, coding and wiring parts
let me explain my project
I am working on an Arduino Project which detects dryness of soil
and starts pumping droplets of water on our roof garden and stops pumping water by checking the moisture level in the soil
can you suggest me the components