If you can find the source outside where they are getting in at you can stop it there with poison.
They are looking for a place to spend the winter.
Is it possible that one plant is rotting. I don't know if they are attacted to that smell.
Get the Terro ant traps or even the liquid. You can put the liquid a few drops on piece of cardboard and they take it back and kill and queen. BUT...I have watched them and some stay right there for like 15 minutes and drink it on my patio.
Eventually after a few days they were dwindling down.
I found the nest in the patio railing cracks and filled it with the Terro foam spray.
In a former condo a neighbor had them and they had a 10 lane freeway outside coming up the wall to her unit.

Ants are secondary infestors, i.e., they're not interested in your house plants per se, they are farming the aphids or scale crawlers that infested your plants at some earlier point. You probably have scale crawlers (which are just about invisible to the naked eye). Once you take care of the primary infestation, there will be nothing to keep the ants interested in your house plants.

not all ants are aphid farmers although that is a possibility. If you moved the pot and saw that many, they are probably nesting in that pot.
I have found that the oil that spritzes out of the rind of citrus makes a good natural ant repellent. Take a citrus rind fold it in half and oil will spritz out of the rind. Spritz your pots and you will find the ants don't like being there any more. I find that lemon and orange work best. The rind must be fresh, not old and dried out.

This may seem strange, but it worked for me.
Cut up a cucumber into slices, then put the slices where you see them entering your home. Maybe they don't like the smell?

I use a houseplant systemic granular pest killer on house plants. It goes into the leaves and as the sucking, chewing pests eat they die. Then the ants will leave. Altho in orchids I usually dunk the whole pot in water and the ants move out but before they do, hit them with more water or soap insecticide Penny

Ants are so easy to control around the house foundation, I don't understand why anyone puts up with them IN the house. Al

i have a lot of house plants too and every winter the ants will move into my plants. i find they are there when i have let the plants get too dry and then water a swarm comes out. what i did this time is: isolate the plant, water the plant well. vacumn up the ants up that will swarm out of the pot. to those of you who revert to poison please stop. we put way too much into our earth that is toxic.