Plant nutrition - Fertiliser programmes. How, When and Why? By Phil I’anson

I always say to our apprentices, ‘never forget the basics, grass needs, food, water, air and light’. This article will deal with the food element, what to feed, when to feed and how to feed.

My best advice would always be start with soil analysis, what is present, what you need and what is lacking. Every winter we take samples of our rootzones for analysis and the results of this will dictate the make up of our fertiliser programme.

I grew up in a military family and there’s a saying in the military that says, even the best plan doesn’t survive first contact with the enemy. Therefore always adjust as needed it’s not written in stone, it will change with the weather, dealing with mother nature is never an exact science, don’t try and fight her, you will lose!

As a base we tend to aim for a granular every 6-8 weeks, we have a Poa / Bent sward on USGA rootzones, obviously different rootzones will need different levels of input  due to leaching and cation exchange capacity. In between the granular applications, we make fortnightly top ups of liquid (sprayed) applications in the growing season and monthly during the cooler winter months as it is very rarely these days that growth shuts down completely. The end result should be a nutrient programme with an approximate ratio 3:1:2 of NPK (Nitrogen/Phosphorus/Potassium). Higher K spring and summer, increased P late spring and N to keep rate with growth. The timings are obviously subject to change depending on the weather but also mainly on clip rate and leaf colour which we constantly monitor. If for example the greens mowers are taking off plenty of grass and a granular is due then there may be no harm in delaying an application.

When considering the liquids, I like to be able to adjust them as and when needed. When mixing a spray I tend to think in terms of base, trace, biology and colour. Applications may also take into consideration competitions and achieving a desired green speed.

Base. NPK what do I want and at what levels? Depending on the time of year and weather conditions. I like to be able to add each element separately so I can vary the amounts. For this I look at different sources of nutrients, Ammonium and Urea for example.

Trace. What trace elements do I want to apply and in what quantities? These will be highlighted in the soil analysis. Keeping them topped up will help greatly with disease resistance.

Biology. Biology makes rootzones (soils) work. Soil biology makes nutrients more available and keeps pathogens at bay or at least in balance. These sources come from humic and fulvic acids, and seaweed. I love seaweed! I think it’s impossible to apply too much seaweed. I also like applying sugars, in the form of molasses. Everyday we go out and cut off part of the grass leaf, which is the equivalent of smashing some solar panels on a house dependent on solar power. So, I like restoring supplemental sugars and molasses, it’s very cheap. Sugar also feeds the microorganisms that make the whole turf ecosystem work.

Colour. Finally colour. I ask myself, how are my greens looking? Will the spray give the desired green up, or do we need a chlorophyll boost. If so, we would be looking primarily at applying more iron. This would be chelated during the growing season. I save the sulphate for the winter to toughen up the plants cell wall.

Fertiliser programmes take time to get right and are constantly evolving. They are not an exact science, but are based on the exact science of lab produced soil analysis. After a while at a venue, you get to know the sward and you really do get a feel for what is needed and when. Just like you know by looking at somebody you know well, whether or not they are feeling OK. Grass swards are the same. They talk to you and you learn to listen to them. The whole process is a balance of feel, knowledge and science. Two of those you can read about and learnt, the other only comes with time, experience and an element of trial and error. Understanding fertiliser requirements can be a challenge to start with. The more adaptable and flexible you and your programmes are, and the more you understand the importance of different sources of nutrition, the easier it becomes to achieve the desired results.