Save water–and money–by watering your garden Mother Nature’s way. All you need is an old water jug or detergent dispenser, paint and some rain.
How to Make a Mini Rain Barrel

Save water–and money–by watering your garden Mother Nature’s way. All you need is an old water jug or detergent dispenser, paint and, of course, some rain.
1. Select a container
Extra-large laundry detergent dispensers make the ideal DIY rain barrels, but countertop water dispensers will also do the trick. The key is that the container has a spout for filling watering cans with ease.
2. Clean it
If you’re using a water jug you can probably skip this step, but detergent dispensers should be thoroughly cleaned so your garden stays suds-free.
3. Paint it
Choose a spray paint in your favorite hue (ideally one that compliments the colors of your garden or patio furniture). Spray the container until the surface is completely covered in an even coat of paint. Leave it to dry overnight.
4. Cut it
With a sharp knife, cut a hole in the top of the container the size and shape of your rain gutter (be sure to measure first where on the container the gutter will enter).
5. Mount it
Remove the cut-away plastic and place the end of the gutter into the hole. Mount your rain barrel on a cinderblock or similarly sturdy item so you can easily fit a watering can under the spout.
5. Use it!
Place your watering can beneath the spout, press the button and fill ’er up.
Source: ReadyMade.com