Question

my garden is full of water,because of yesterday's rain . correct punctuation

Answer 1

Capitalize M in My and one space after the comma = , because

My garden is full of water, because of yesterday's rain.

Sra

Answer 2

There should be no comma in that sentence. Commas are needed AFTER subordinate clauses that introduce a sentence, but NOT BEFORE them when they come later in a sentences.
http://grammar.ccc.commnet.edu/grammar/commas.htm
See #3 and #11.