Understanding N:P:K Ratios

WHAT ARE N:P:K RATIOS? If you are new to fertilisers, they can be tricky to understand until you know what certain numbers mean. No matter what type of fertiliser you buy, it will come with information about the nutrients that it contains. The most noticeable will be the N:P:K ratio. This is the percentage of nitrogen (N), phosphorus (P) and potassium (K) that the fertiliser contains. Both synthetic and organic fertilisers will display an N:P:K ratio. For example our Amvista G0 Kick Start Fertiliser is a 10-4-4 which translates as 10% nitrogen, 4% phosphorus and 4% potassium. Nitrogen (N) is generally considered the most important nutrient and most plants will use more nitrogen than any other nutrient. Nitrogen is essential to form the proteins needed to help plants grow. High doses will encourage lush soft growth which can make plants prone to disease, pest and frost damage. Avoid using high N fertiliser in the autumn and try to use slow release products like Amvista G6 or Arbor Gold Phosphorus (P) promotes root development making plants quicker to establish and more stress tolerant. A stronger root system will help the plant survive draught periods and also access soil fertility. Potassium (K), also known as potash. Potash helps plants to fight off diseases and is important in water regulation. Potassium is also critical in the formation of flowers and fruits. Symptoms of potassium deficiency usually show as stunted leaf and fruit growth alongside being overly sensitive to drought conditions. On top of containing the primary macro nutrients nitrogen, phosphorus and potassium, many fertilisers also contain other secondary macro nutrients and micro nutrients. These are required in much lower amounts but are still crucial for healthy growth. Common additions are calcium, magnesium and sulphur which all have different qualities to add: Sulphur (S) – Critical to the metabolisation of Nitrogen. Without sufficient sulphur plants can’t efficiently use nitrogen. Calcium (Ca) – Used in the production of cell walls. Particularly important in roots and shoots. Manganese – Necessary for photosynthesis. Magnesium (Mg) – A key ingredient in chlorophyll, the driver of photosynthesis. This also makes leaves a darker green. Iron (Fe) – Used in chlorophyll production. Typically iron is in high enough quantities in the soil, however, it is often added as it will control of moss in turf Other micro elements include Boron, Molybdenum, Copper, Sodium and Zinc among others. Explore our full range of fertilisers here. SOIL ANALYSIS In order to know exactly which fertiliser is best for your soil, we recommend you carry out a soil test. With these results our FACTS trained specialists will be able to advise you on what is needed to correct deficiencies and what should be avoided to prevent overdosing. Check out our range of soil analyses here.

Understanding N:P:K Ratios

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