We know Google said that Google can index and rank non-HTTPS URLs and content. And yes, that means Google can also crawl non HTTPS URLs. Google’s John Mueller actually confirmed on Twitter that yes, Google does crawl non HTTPS URLs.

Here is the Q&A on Twitter:

Like we said before, there are a lot of myths out there on HTTPS and as you know, HTTPS is a tiebreaker signal, super light weight signal. So it isn’t that important for ranking, indexing or crawling purposes.

Forum discussion at Twitter.