What causes gnat infestation?

Related questions

1. Will raid kill gnats?
2. Do gnats die off in the winter?
3. How do you get rid of swarms of gnats?
4. Can bleach kill gnats?
5. Will fly spray kill fruit flies?
6. How does Dawn dish soap get rid of gnats?
7. Will drain flies go away?
8. Why do I have gnats in my bathroom?
9. How do you get rid of gnats in sewer?
10. Does Drano kill drain flies?

Tags

1. #houseplants
2. #inside
3. #found
4. #attracted
5. #homes
6. #flying
7. #house
8. #infest
9. #fungi
10. #infested
11. #plant
12. #fungus
13. #damaged
14. #usually
15. #roots
16. #decaying
17. #brought
18. #gnats