Answer: hotbeds

AnswerCrossword Clue
HOTBEDS

Fertile spots

HOTBEDS

Activity centers

HOTBEDS

Sources of unpleasantness

HOTBEDS
Busy places
HOTBEDS
Glass-covered enclosures in greeneries
HOTBEDSPlaces favoring rapid growth.
HOTBEDSGardener's concern.
HOTBEDSPlaces for seedlings
HOTBEDSCenters of activity
HOTBEDSBreeding grounds
HOTBEDSPlaces of great activity
HOTBEDSAreas of rapid growth