Banana peels, molasses or the pill. No kidding intended.
Banana peels (or even apple or cucumber peels) produce ethylene, a gas taht forces the accelerated production of most all plants. Some growers will actually tell you that banana peels, placed on top of the soil or even in the soil can raise the chances for you to get a female out of a regular seed and will definitly shorten flowering and raise yield.
The pill, which essentially contains estrogen has been proven to accelerate flowering. This test was made by farmers on several farm plants (tomatos, carrots etc) by mixing the pills in the watering solution.
Molasses contains carbohydrates and all necessary microelements the plant and buds need to grow. The carbohydrates feed the microorganisms in the soil, these in turn break down the soil into absorbable nutes and substances for the plant.