Though fungus gnats aren't so big a problem taking out the larvae with spinosyn a,d ..this is a sight better than I've seen hanging the cards alone.
To install then 2 ways 1
Be sure to leave covering on till the end.
Cut the cards into desired sized strips .
Split the strips down the center so as to have one sticky side one paper side, you can do it.
Method 1 staple them to the cloth pots
All around the top inner and or outer of the pot , then pull card covering off may be tricky with staples.
Method 2 tape blue painter's tape preferably, run the tape all around the outside sticky side out so as to stick to the bug card holding it in place .
Keeping in mind that you may not want to move the pot by Grabbing the edges ,no braino.
I'm trying good old tape next to make it cheaper will update the write up later.
Hope its ledgable..





