How can i stop vines from growing inside my underground base??

[TheFedoraInTime]

My entire base is filled with a lot of vines after i come back from my second outpost.

 

[karadoc]

Replace the ceiling with bricks or rocks or something other than dirt. Then vines won't be able to grow.

Or if you really want a dirt roof... remove the green growth from the dirt, and then put a barrier at each end (eg a brick) so that the growth doesn't spread there again.

 

[CannedPotato]

Is this because your roof is grass tiles? There are a few ways to answer that, the most accessible way would be to place platforms on your ceiling, you can use any type of platform for this but I think a brass shelf would be the most subtle. You can also find them in the dungeon on any platform but that is rather slow and painful, again, any platform will do the trick.

Another solution could be to place blocks at your roof and actuate them, this requires wiring tools but may be preferred if you can pick a block that thematically suits your house, since you have a grass based roof I think actuated living leaf could fit very well, you can also paint them if your house is in a hallow biome to the look of pearlwood trees.

And the final, perfect solution to the issue, echo blocks. Specifically actuated echo blocks.
You need to have beaten Plantera, but if you have you can buy echo blocks/platforms from the cyborg in a graveyard. They are invisible unless you are wearing spectre goggles and prevent vines from growing on them, use actuators on the blocks after placing them to make a completely invisible and untouchable block which also blocks vines!

 

[The Triangle God]

Actuated echo blocks or platforms with echo paint and cover the roof with them