Do NPK fertilizers contain all three elements (nitrogen, phosphorus and potassium) in them or just 1 of the three elements?
They contain these three in one form or another. Often they also contain other elements/compounds such as trace elements, weed killers, etc.
NPK fertilizers do contain all three elements - nitrogen, phosphorus, and potassium. The term "NPK" actually stands for the chemical symbols of these three nutrients.
To determine if a fertilizer contains all three elements, you can check the label or product description. Most fertilizers will clearly indicate the NPK ratio, which represents the proportion of nitrogen, phosphorus, and potassium in the product.
The NPK ratio is typically represented as a series of three numbers separated by hyphens or slashes. For example, a fertilizer labeled as 10-10-10 contains 10% nitrogen, 10% phosphorus, and 10% potassium. The order of the numbers corresponds to the order of the elements: nitrogen-phosphorus-potassium.
Keep in mind that there are different types and formulations of NPK fertilizers that cater to specific plant needs, so the ratio may vary. Some plants may require higher levels of certain nutrients, so it's important to choose a fertilizer that suits the specific requirements of your plants.