How long exactly does it usually take before a site starts getting organic traffic?

[r_desai]

How long  exactly does it usually take before a website starts getting any organic traffic? One of our site is just two weeks old. And we have done almost everything in terms of on-page optimization. We even submitted the sitemaps through webmasters toll and also fetch the urls manually. So, I am getting curious here. At present we are only getting some referral traffic and few hits from social media channels.