Well, if it's a full beard you want, look no further than the nearest mirror! That looks great for five weeks.

Now, if it's a thicker full beard you envision, plan on growing for at least the full 13 weeks the others have suggested. At that time you'll be nicely set to decide what style and shape you want.

Cheers!
Tom


Some helpful links:
Library Central of Beard Growing


Taming the Wild Mustache
Tips for eating and drinking with a big mustache

Excess on occasion is exhilarating. It prevents moderation from acquiring the deadening effect of a habit. ~ W. Somerset Maugham
A jerk with a beard is just a bearded jerk, but a bearded gentleman is awesomeness personified. ~ Triibeard