No, you would need to file the state extension separately in addition to the federal.
If you already completed (or are mostly finished with) your 2018 state
return in TurboTax Online, go back into your state and look for a Need more time to file?
or similar extension question or option, usually towards the end of the
interview (step through your state again from the beginning if you
didn't find it). Then follow the onscreen instructions in TurboTax.
Otherwise, if you haven't (or you just) started your 2018 state return, see the link below for information on how to file an extension on your state's web-site:
https://ttlc.intuit.com/replies/3300227