Thanks for your help.
Yes I am in Florida...we get a lot of rain.
My garden consists of several beds that are now in Garden bins, hanging pots and 4x4 raised beds. I have drip lines going to each that currently comes off tap water and I want to switch to rain water.
I was thinking I would try to replicate something like this as far as a barrel goes:
http://www.composters.com/rain-barrels/the-rain-catcher-rain-barrel——54-gal_160_10.php
It is important that you have a good filtration system if you are using micro-drip to avoid plugging the emitters. We have municipal water but it is getting expensive as the city tries to balance the budget by rate increases. Our roof run off in collected and drains over the hill and I have considered purchasing a large water tank to catch that water and pumping out of it for the garden and I have even thought of hand digging a well...