NOOB QUESTION! best way to water indoors??

hey i have a plant in my closet and its getting to big to carry outside to water it, i have it sitting on a garbage bag, my question is what is the best way to water it??

i have carpet under the plant and i dont want ANY Mold.. how do all you big growers do it?

I use one of them plastic bases you use for washing machines. When I have water pool in it I just mop it up with a towel. If you dont have that room you can build a square with 2x4's and cover with plastic.

im only growing one plant atm, i will be building somthing like that for my next grow.
but you gave me a great ideal im going to use a laundry basket with a garbage bag around it.. thanks man!

heres the plant! its a beast