I just wanted to know because sometimes its only like 20 minutes, but other times it's 300 minutes

Oh, and this is right after they've been harvested

The crops are on a specific time cycle, so how long you wait depends only on how quickly you pick the current crop.

Oh, ok, so picking the crops faster will make them grow faster?

no.. it won't. Let's say the crops are due every quarter, at the beginning of the month... if you pick the Jan-March crop by Jan 31st, you have to wait 2 months for the April 1st crops to come in; if you finsish picking by Feb 28, you wait 1 month... and if you don't pick them by March 31st, what remains is spoilt and replaced by the new crops anyway

OOoh ok, thanks :-)

Thank you, Bajantara, for that last point. It was exactly what I was wondering about.