Over recent years there has been significant development in peat-reduced and peat-free growing media, as the horticulture industry edges ever closer to a peat-free world. Extensive trialing of raw materials means that there are now some excellent peat-free products on the market – says Brendan Howell, Sales Development Manager for ICL Professional Horticulture across Ireland.  However, both the physical and chemical properties of these materials – commonly bark, coir and woodfibre – are quite different compared to peat-based medias; they have a naturally higher pH and a greater air-filled porosity (AFP).  

New way of thinking  

In order to really get the best out of peat-reduced and peat-free mixes, they require a new way of thinking and managing, particularly when it comes to fertilizer and nutrition requirements. That’s where ICL’s new Osmocote 5 s-curved release pattern really helps.  

With its enhanced nutrient release, new trace element system and higher nitrogen content, Osmocote 5 helps overcome the challenges of higher pH and lower nutrient buffering that can occur with peat-reduced and peat-free growing media. Osmocote 5 builds on the success of Osmocote Exact Hi-End and has been developed specifically for use in peat-reduced and peat-free mixes.  

Higher AFP 

Peat-reduced and peat-free growing media mixes are generally more open with a higher AFP. This not only aids root development, but also means the mixes will be more free draining than a peat-based mix. This is good news as it can help prevent plants from sitting wet, particularly overwinter. However, because the mix is more free draining, it does mean nutrients can be leached from the growing media more quickly. In addition, the woody alternatives to peat - commonly bark and woodfibre - can hold on to nutrients, particularly nitrogen, locking them up and making them less available to the plant.  

Combatting N lock-up 

ICL’s peat alternative products have been extensively trialed and refined over the years to help combat nutrient leaching and lock-up, particularly Fibagro Advance woodfibre. This product is manufactured in such a way that when it is blended with other raw materials, the water and nutrient holding capacity of the peat-reduced or peat-free growing media is increased. However, adding Osmocote 5 to these mixes optimizes the nutrition in the media, ensuring plants receive the nutrients they need, when they need them. The higher N content also helps to mitigate against any nitrogen that may remain locked up in the media.  

Moving away from peat doesn’t have to be scary. The peat alternatives ICL uses are high quality, sustainable and hugely successful. Now with the introduction of Osmocote 5, growers can rest assured they are getting the best product possible to grow top quality plants in a sustainable growing media.