Set a Background Image for Blog

Hi Guys,

my main website is at http://onlinediamondbuyingguide.com. As you can see from the side panel, there is a chequered background with a light blue backing.

On my website’s blog, http://onlinediamondbuyingguide.com/blog/ the side panel is a full solid color of grey.

My question is, how can I change or modify the background of the blog to include the chequered background image that i use for the main site?

I want to do this to achieve consistency in terms of the appearances.

Thanks alot!
Paul