How do I Know How Much Nitrogen, Phophorus, and Potassium my Fertilizer Has?
In the United States, the big numbers on the labels of all fertilizers, called the NPK numbers, give the percentage of each of the three main macro-nutrients in this order: Nitrogen (N) – Phosphorus (P) – Potassium (K). (These numbers measure different things in some other countries, so check your country’s system before applying the numbers to your hibiscus care.) When looking for a fertilizer for hibiscus, look for this ratio: Medium – Low – High. If all three numbers are the same, as in most “Superbloom” formulas, there is too much phosphorus and too little potassium for hibiscus. The ratio we have found to be the best is the one we use in our HVH Special Blend Fertilizer: 17-5-24. This is the fertilizer we developed for our own hibiscus, after much trial and error. You don’t need this exact ratio, but you do need this pattern of Medium Nitrogen (N) – Low Phosphorus (P) – High Potassium (K). How to Read Fertilizer Numbers If your fertilizer has less-than-optimum levels of potassium
