I have had the lights on my sativa plant on 12/12 for almost two weeks now. I can see a few hairs here and there coming off the base of the stem at the nodes, but none so far coming from the ends of the new growths where the buds will eventually be. How long on average does it take for plants to begin developing real buds??
Typically after the stretch phase of flowering the buds will begin filling in and fattening up. Here is a general guide called the The 40/60 Phenomena written by pH: The 40/60 Phenomena are events observed during the indoor cultivation of flowering cannabis, and when using a strict 12 hour inductive photoperiod (aka 12/12). The events start with the first day of the inductive stage (12/12), and end on the day a mature crop is ready for harvest, collectively this period of time is called the Days Spent Flowering. Stretch Phase (early flowering) The stretch phase is a period of time during early flowering where rapid extraordinary outward growth takes place. Some growers have reported seeing 5 inches of growth in a single day during the stretch. This phase is characterized first by the extraordinary growth accompanied by longer than usual internodes, then the explosive outward growth slowly tapers off as internodes shorten. The end of the phase is signaled when growth tapers down to approximately 1/2 inch or less per day. This coincides with a time span equaling 40% of the total Days Spent Flowering. At this point growth shifts from outward to building bulk on existing growth, otherwise known as late flowering or the fattening phase. Fatten Phase (late flowering) The last 60% of the inductive phase is a period where outward growth is less significant. In fact, it can appear as if growth has stopped completely due to the very short internodes. During this phase a more complex set of growth activities occur. It's not much different from an apple tree that stopped producing new apples and is now devoting its remaining time to maturing or ripening the apples it already has. With female cannabis, flower production accelerates, floral clusters begin to grow wider or fatten, resin production increases and peaks, sinsemilla calyxes plump, pistils start to wither and change color, and not long after that the plant is ready for harvest.