There are many things at play here and you might be wasting your time trying to solve an X/Y problem
If you are 100% certain that you need a search box in the navigation then from a design perspective I'd personally say that there is not enough contrast and only after a heavy "Make me think" session would I see that button.
Just look at the contrast for the search box on this site.
If the site is unintuitive enough that a user reaches for the search bar right away then that is a cry for help in other areas because my experience has been that most site's search features are so broken I stay away from it at all costs (this is not to say that filtering stuff doesn't work). Even on http://www.stackoverflow.com I never use the search bar but rather use Google to Google the site =) I often find myself filtering with the tags on the right-side of https://stackoverflow.com/questions
I am not sure about your entire navigation but if there are only 5-6 pages of content then I highly doubt you will benefit from even a superb search functionality.
Maybe one of the pages, like the blog, has a bunch of stuff that the user might want to sift through. I would put a prominent search box right on that page only or maybe some sort of filter system where they can select a date range and some categories.
http://www.amazon.com/ fills their page with potential items you might want to buy but if that fails then the search bar is quite prominent.