Oh, yes - it works. I've often done it when I want a
plant to be protected - it helps hold the moisture too.
This one has the hole at the top, but when it's just the bottom of a pop bottle I slit a hole in it so the air can get in.
That one you see in the picture has summer savoury, wild oregano in it - and you know what's in the middle?
Heh! Heh! I know I'm a nut - but so is that thing that you find in the centre of the avocado. I'm curious to see if it produces anything.
I have a small
seed from an avocado nut - I'm going to poke that in some soil too. I love experimenting.