N-P-K, or the (0.05-0-0.10) nutrient ratio, stands for Nitrogen (N), Phosphorus (P), and Potassium (or potash)(K). More nitrogen is used during the vegetative stage, and the plant loves phosphorus during flowering. You'll need a fertilizer with a higher phosphorus level to produce heavy buds. Go with an organic fertilizer if you can, but even a Miracle Grow bloom booster would work better than what you have now...and I'm not a fan of chemical fertilizers at all. I like using bat guano, though there are also a lot of other & more water soluble nutrients on the market.