Why are new sites created with http instead of https?

Hi there,
i am running a WP multisite with subdomains, the whole site (hosted on WP Engine) is SSL enabled, certs for main domain and also wildcard certs for domains used for multi-domains sites are installed and working.

But,.. if a new site is being created, it always gets setup as a http site, instead of https (siteurl and home url are always http://domainname

How can i change that, how can i auto create https sites when a new site is created on my multisite. (instead of forcing https calls via htaccess etc.)?

tnx, Eric