Hotbed
Breeding Ground
noun
A warm bed is a "hotbed."
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
この公園は地元では犯罪の温床になっていることで知られているので、近づかない方がいいですよ。
This park is known as a breeding ground for criminal activity in this area, so you shouldn’t go near there.