You have to wait until they turn into pine cones and the lupulin glands have matured. Otherwise it's as dumb as smoking the first cottonball buds on your cannabis plant!

It's a pretty obvious effect almost immediately. Just keep smoking up until you get to the level of sleepiness you like!

I hear ya gmoney, I used to use Nyquil to get better sleep but it just gives me a horrible hung-over logey feeling the next day.