Here’s another summer phrase that is useful even if it is not yet summer: like watching grass grow.
You can use this phrase to say that something is very boring or uninteresting.
A: Me and my husband have a date tonight, so can you watch the baby for us?
B: Sure! It’ll be fun!
Later, while the baby is sleeping...
B: I thought it would be fun playing with the baby, but the baby has been asleep the entire time! It’s like watching grass grow.
A: Have you seen that love story movie where two characters just talk the entire movie? A lot of people liked it!
B: I fell asleep 15 minutes after the film started. It was like watching grass grow!