tempature drop at night?

i have heard the you dont want your temp to drop more than 12 degrees? my temp during the day is 84 to 90. when my lights go off it drops to 64 or around there. is that bad?? what should it be? thanks for the help it is much appicated.

64 aint too bad for night i shoot for 74*day and 68*night.
90* is a bit on the hot side try getting close to 80*days if you can.
2* either way wont matter at night.

The biggest effect will probably be longer internode spacing, which will be perceived as stretch. There is a direct relation to the change in temperature between cold and hot and the internode spacing.

they stay close together as for the plant does'nt grow as fast. (shorter busher plant)