Ups and downs of self-mixing CRFs

19 June 2020
  • Whastsapp

With 20 years experience of self-mixing growing media on a large UK nursery, our new technical area sales manager Steve Chapman outlines some of the advantages it offers.

There is more than one way to skin a cat, as the saying goes, and this is so true in the world of commercial horticulture.  In my 20 years of growing and visiting nurseries around the UK and Europe I have never seen two identical operations.

Growers are faced with many crop management challenges – plant nutrition and plant protection being two major ones.  In my previous role as a production manager I had plenty of first-hand experience of self-mixing controlled release fertilisers and crop protection products. While it does not always offer the cost saving benefits of having CRFs included in your growing media mix, it gave me ultimate control over rates and types of fertiliser.

Smaller nurseries often do not require the volume of growing media, or indeed have the space or finances, to install mixing equipment.  As a result, they are often bound by these constraints to having one mix and rate to satisfy the needs of a range of crops.

There are pluses and minuses to self-mixing, for those doing it you must make the most of it as self-mixing gives you ultimate control over every individual crop. 

ICL has an Osmocote product for just about every crop situation.  By self-mixing, you can take advantage by upping or lowering the rate depending on the plant’s needs, switching to an Osmocote Exact Protect in the autumn to delay release until the New Year, changing the longevity to suit the sales period or even switching to Osmocote Exact Mini for potting up small liners.

With the evolution of 4th generation Osmocote products, the features and benefits got broader.  Osmocote Exact Hi.End, for instance, by delaying initial release is ideally suited to salt sensitive crops like Choisya and Skimmia.   Employing new double coating technology, it allows the plants to get their roots down before the full rate is released and then continues releasing later when the plant really needs it. As well as nurturing excellent root development and branching, it promotes leaf shine and colour, thanks to the full trace element package and optimised iron release.

UK nurseries are under constant pressure to diversify further to meet the growing needs of customers. So, if you are self-mixing CRFs this is a perfect opportunity to maybe switch to an Osmocote High K product for herbaceous perennials. Compared to a high nitrogen product, this high Potassium formulation helps avoid stretched plants − which tend to be taller and more easily blown over − helping to save labour and wastage.

Top Tip

One common mistake is often made when potting up old plants.  Maybe you have some leftover 3-litre plants, that have ran out of the original fertiliser incorporated the previous year, which you want to pot into a 10-litre. Growers often seem to forget that the 3-litre pot has no fertiliser left.  This needs to be taken in to account when mixing the additional growing media, otherwise a rate of 4Kg will be closer to 3Kg - most likely resulting in a nutrition deficiency, or even making the plants more prone to pests and diseases.

Whether you decide to opt for tailor made mixes or self-mixing, ICL’s team of technical area sales managers are on hand to help you get the very best out of our products.