Hashtag does not show up in Google search

Hi there,
I am trying to collate postings from a number of different social media platforms by using a hashtag. I tested the hashtag and it is unique. As a trail, I have uploaded a number of images to Twitter and Instagram using the hashtag. When I however do a google search not results are returned. Am I doing something incorrectly or do I just have to wait? and if waiting is the answer - how long? Your expert opinion is much appreciated. Thanks,