Less nitrogen.
More phosphorus.

Nope, phosphorus doesn't matter at all, chromatic analyses clearly show that phosphorus uptake doesn't increase notably during flowering stage of any plants. Just another myth among so many others - I believed that too a while ago. Nitrogen has only to be lowered if vegetative growth is clearly excessive and there are no buds forming, or if the formula has N-excess anyway. During flowering and fruiting stage, plants need increased Potassium and some more Nitrogen as well. In most cases Nitrogen is sufficient, though - just ensure 250-280 or even 320 ppm of Potassium during flowering stage instead.

Light cycles do not play on flowering/fruit setting with peppers, this "knowledge" is commonly but falsely reported/transfered from MJ-growers. Peppers can/will flower and set fruits with various light cycles. Even if some varieties are called C. Annuum, they are no actual (biologically or technically) annuums and hence do not depend on seasonal light cycles. Many species and varieties actually originate from the equator region, where the light cycle is close to 12/12 all year long.

More important in this context is to have lower night as day temperatures, and enough air humidity for optimal and proper pollination.

In some cases fruit setting of peppers is simply delayed, because the plant is not mature enough (even if you guess it might be). In that case patience is the best cure ;-)

Flower drop probable causes:

1. Day temp too high >95F
2. Night temp too low 3. Too much nitrogen fertilizer
4. Too much water (in dirt, not hydro)
5. Low light levels (reduces fertility).
6. Very low humidity (reduces fertility)
7. Poor air circulation (air circulation contributes to pollination).
8. Lack of pollinating insects.
9. Size of pot (pot-bound)

10. Too much mineral in feedwater.
11. Too much grower attention.

The light cycle does not matter but the total amount of light a plant receives a day does. Good production requires from 28,000 to 41,000 Foot-candle hours per 24 hour period, depending on the light source. (28K lux for 16 hours from an HPS bulb, for instance.)

Mike

The 12/12 photo cycle allows more flowers to bloom. Also a good supply of potassium and some phosphorus will also be essential at that stage.

Nope, light, photo or whatever CYCLE doesn't play with pepper flowers and blooming. That's one more of a zillion falsely transfered/transcribed myths from Mj-growers bigger bud stories ;)