What Are the Main Requirements for an Effective Potato Fertilizer?

History tells us that the humble potato was possibly the first domesticated vegetable. Millennia before its eventual appearance in Europe, Africa and elsewhere, this popular root crop was farmed in parts of South America from as early as 8000 BC. Today, this starchy favourite has since become an essential part of a meal in many cultures and, like rice, a staple source of dietary carbohydrates. However, farmers require a carefully formulated potato fertilizer to grow the vast quantities of this vegetable consumed today.

The NPK Requirements of a Potato Crop

Like all growing plants, this crop requires a sufficient quantity of the three essential macronutrients, Nitrogen (N), Potassium (K) and Phosphorus (P), in the correct proportions to thrive and produce high yields. The precise needs may vary according to the chosen variety and the soil composition at the planting time. Rather than attempting to judge the latter by its feel and appearance, it will be safer to arrange a professional soil analysis. Potatoes thrive best in slightly acid soil. Applying sulphur lowers the pH while adding lime will increase it.

An effective potato fertilizer must be equally rich in phosphorus and potassium while containing about half their weight of available nitrogen. In theory, a product with an NPK ratio of 5-10-10 should adequately meet those requirements. During the early development stage, the lower nitrogen level prevents the foliage from becoming too lush and more prone to disease. By contrast, the higher potassium and phosphorus concentrations will help stimulate the growth of large, healthy tubers. However, your soil analysis will also indicate the quantities of these elements already present in the untreated soil. Ideally, the macronutrients in your commercial potato fertilizer, combined with those in your planting area, should add up to the optimal NPK ratio.

Furthermore, although the nitrogen requirement might be lower, it is still an essential macronutrient. Unfortunately, heavy rainfall leaches nitrates from the soil, leaving it depleted. It is, therefore, necessary to provide the crop with nitrogen in a form that is more readily retained or to include a suitable stabiliser in the mix. In addition, a granular potato fertilizer releases its nutrient content gradually and will continuously replace that lost due to leaching or utilised by the growing plants.

Benefit from a Bespoke Soil Analysis

When considering the differing requirements between varieties and marked variation in the soil composition, the best option for growers is to implement an appropriate fertilization programme, an area in which Kynoch specialises. Let us conduct a detailed analysis of your soil and formulate a potato fertilizer tailored to your proven requirements. If you would like to learn more about our innovative professional services to farmers, please click here.