Working with tables

I’ve been having a problem. I want to create a table that has 4 boxes in width, with an unlimited potential in height. My “main content” is 598px. When I reach 4 boxes I want it to automatically start a new row when I insert more picture. When I continue the process and add the same table code over 4 time, the 5th table goes into my “right side bar” and doesn’t go down when it has reach the size limit of the main content. How would i fix this? here is the code

Main content:
#content #picture {
padding-top: 20px;
width: 598px;
position: relative;
float: left;
margin-right: 5px;
margin-left: 5px;
}

Table attributes:

Flowers