Student or Learner
In some houses there is a special small room for keeping and growing plants.
What do you call it, please?
This enclosed area (room) is small and usually has glass walls.
Is herbarium good to use for this? Can everybody understand it?
Some people might call it their conservatory. ('A greenhouse usually attached to a house' - Collins)
I'd assume a herbarium was used for cultivating culinary or medicinal herbs.
So a conservatory can be the kind of room inside a house that I mean. Am I right?
When I googled it I had better results than herbalium. But all the pictures show an enclosed area outside.
I think the problem is the original sentence: In some houses there is a special small room for keeping and growing plants.
If English4everyone really means a a room that is in the house, then most of us simply don't have one.
I believe conservatory is the best answer so far.
They're not actually inside the house, nor outside. They are attached. But they aren't just any small room that you choose to keep your plants in. They're specially made to let the heat and light in (which is why I, as an Aussie, didn't think of this straight away, because we tend to get enough heat and light in our homes).