Understand Fertilizer

Unpacking the NPK ratio

Gardeners often categorize different kinds of fertilizers with a universal ratio. The NPK value indicates the ratio of nitrogen to phosphorus to potassium. For example, a NPK of 1-2-3 would mean 1 part nitrogen, 2 parts phosphorus, and 3 parts potassium. If the ratio isn’t simplified, such as 6-10-10, then the fertilizer is more potent and likely synthetic. Bags of fertilizer will indicate the NPK value on the package.

  • Nitrogen

    Nitrogen is perhaps the most important nutrient for healthy and strong plants. Nitrogen promotes rapid and healthy leafy growth. While some plants thrive with lots of nitrogen, others can’t handle much. Fruits such as peppers and tomatoes won’t produce very many flowers if there is too much nitrogen in the soil.

  • Phosphorus

    Phosphorous mainly promotes healthy root development but also aids in flowering and seed development. Plants that rapidly produce above ground growth with shallow roots such as legumes and lettuces require plenty of phosphorus.

  • Potassium

    Potassium is essential for a plant’s ability to transport nutrients, water, and carbohydrates. It is also used in enzyme production and regulating gaseous intake through the stomata. Potassium is especially important for flowering and fruiting crops.