Question
Hi :)
Im doing an advertising assignment for university, and i need to know how long it takes for a petunia flower to sprout, how long it takes for an unopened blossom to appear and how long then it would take for the blossom to open.
Thanks for the help!

Answer
Mykelle,
A petunia plant takes 12 to 13 weeks from sowing a seed until it begins to bloom.
Once flowers are formed, the flowers usually take between 6 to 9 days to open. It's hard to say the amount of time from unopened blossom to open, since who is to say when it begins to be an unopened blossom. Is it when it's first noticeable, and doesn't that depend on how good your eyesight and knowledge of the plant are?  So that one is too subjective.

I hope this helps,
C.L.