system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do houseplants know what season it is?

How do houseplants know when it is time to grow and bloom and when to die back. I grow daffodils in my kitchen which is a pretty consistent temperature all year round however, without fail my daffodils will bloom in the spring and die back over winter. How do they know when to do this? 

Edit: Thanks everyone for their responses. I understand how it works now.
gpt
They get varying amounts of sunlight every day.  Short days = winter; and long days = summer.  Temperature varies every day and swings over a large range.  It's not as reliable as sunlight.  Some plants, like cherry trees, do use ground temperature, but they bloom very early in the spring.