oddish you have to get him at night time
yes, morning, day and night will be in HG/SS
they come out mostly at night.
route 30 night only
anywhere in kanto at night
Bellsprout tower at night time.
forest at night
Yes, in Safari Zone at night. And in Route 16 and 7 also at night.
go to the sprout tower in the town where you get the first badge at night.
Level it up at night whilst it has high happiness.
It is found in Routes 7 and 16 at night and in the Safari Zone.
You can get a spinarak which evovles into ariados by searching in the grass, at night, to the right of violet city