Mind your Ps & Ks!

Besides nitrogen, the most important plant nutrients are phosphorus (shortened to P) and potassium (shortened to K – we don’t make the rules!). Both nutrients are critical to life for all plants, needed for photosynthesis, healthy root growth, and even forming the building blocks of DNA.

Unlike nitrogen, grass will not tend to become overly lush where phosphorus and potassium fertilisers are supplied, so these can be considered safe to apply where soil analysis indicates that they are needed. Soils deficient in P and K will have weak, unhealthy plants that cannot recover from equine grazing.

The most accessible source of these nutrients is manure, which can help us to build up these nutrients where they are lacking, to support better grass growth Chemical fertilisers can also be used where there is a more severe deficiency. 

On the other hand, too much of these nutrients can encourage nutrient loving weeds such as nettles and docks. Ever wondered why nettles love to grow around piles of droppings? It’s the nutrients! It is therefore important to analyse your soils before applying any manure - this is definitely a situation where you can have too much of a good thing! 

The importance of pH

The pH or acidity of soils is critical to plant health. If soil becomes too acidic, important plant nutrients get locked up while potentially toxic elements become more available. This can cause plants to become unhealthy and potentially have an impact on the health of our horses.

The target pH for grassland is 6.0, as this allows the optimum balance of available nutrients within the soil. The only way to know whether your soils need lime and to calculate how much to apply is to analyse your soils for pH. Soil pH can be analysed on its own or in combination with other plant nutrients.