Fertiliser & Turf Nutrition

Hello everyone

I have been aiming to put out a blog post on the use of fertiliser for a while now - specifically to answer a range of questions and provide some (hopefully) informative content. This week, we have carried out this task too so it's perhaps a good time to explore this topic.

Obviously, any members reading this might reasonably ask "how does this affect me and my golf?" So with that, let's dive in.

Fertiliser is plant food, in basic parlance.

We apply it several times per year and always on the back of a soil test. For this blog, let's focus on greens as they are the most important area of the golf course.

The main reasons we apply fertiliser are as follows:

• Turfgrass growth
• Turfgrass recovery
• Turfgrass resilience
• Surface uniformity
• Correction of soil nutrient deficiencies

Before we look at each, let's clarify that fertiliser is only applied to golf greens because there is a genuine need for it. We don't apply it for any other reason eg a company sales rep is providing us with a cheap 'deal'.

Turfgrass growth

All grasses need fertiliser for growth so that we can meet the seasonal demand for mowing, irrigation, aeration, topdressing - and play of course ! The main source we are most concerned with is Nitrogen. It is the mineral most required for turf growth. 

Nitrogen is available in many forms; Urea, Ammonia, Nitrate are perhaps familiar to some of you. Each provides growth in different ways. Some release that Nitrogen quickly, others more slowly. Often, these Nitrogen sources are blended together to provide both immediate and longer term impact

In terms of growth itself, we are aiming to provide just enough to provide a putting surface but not too much whereby grass is being siloed off daily by the mowing machinery. We don't want yield. Moreover, it is density that is sought so that the surfaces are resilient

Turfgrass recovery

This is fairly self explanatory but we need recovery as the golf played on the greens can be quite intensive. Think of all the competition play and how full the BRS tee sheet can get. Hence the greens turf needs to be able to recover after a day's play. When we undertake processes such as verticutting or mowing or topdressing, these can all impact the surface and that's also why greens turf needs nutrition

Turfgrass resilience

Related to the above points, different forms of nutrition affect the turf in different ways. Potassium is useful for stress, Phosphorus for rooting and seed development, Iron for colour and hardiness. 

In particular, the different seasons and varying weather patterns all affect turf resilience. It might be a drought period where little rain has fallen but golf is still being played regularly. It could be intensive periods of heavy rain where the surface is being endlessly saturated. Or it could be very short days in Winter when there's little sun and lots of darkness. 

In all instances, there's generally a second order effect on the turf. This might manifest in turf disease or turf thinning or turf discolouration. Hence the need for appropriate nutrition to support the grass.

Surface uniformity

How do we get a smooth surface for putting on? We fertilise for growth, ensure the mower is set up to provide an even cut, cut or roll according to growth and seasonal demand, apply irrigation (in the event of no rain) and topdress to smooth out the surface depressions or irregularities

But essentially, fertiliser provides the means for the other tasks to be carried out effectively

Correction of soil nutrient deficiences

Generally, these are determined by a soil test. Then a suitable fertiliser is applied to address any identified issues. It's a bit like taking a multi vitamin. The food you consume might not quite be enough for you and the needs of your body. The same principle applies with grass

So, we've identified different needs. Now let's look quickly at their application and how these can impact golf.

Generally, there are 3 types of fertiliser; granular, liquid and soluble. Granular is generally a pelleted/prilled form, liquid is diluted with water for spray applications and soluble is in a pelleted/prilled or powder form that is dissolved in water and for spray applications. 

Granular fertilisers have more longevity. Liquid fertilisers are very short lived. Soluble is a mid-point of the two, generally. Application of granular fertilisers generally entails less frequency/labour time whereas liquid applications demand frequent labour time. Granular applications take time to break down, liquid applications have no interruption to golf. 

Fine granular fertiliser (above)

Which is better? Personally, I prefer granualar fertilisers as we're feeding the soil. Our USGA (sand based) greens can also leach nutrients as sand generally doesn't hold onto nutrient like a clay based soil does. Hence the nutritional demands for sand based soils are higher. 

The downside, and it may be observed by golfers, is that granulars can take up to a week to fully break down. The implications can be quite testing for golfers and greenkeepers alike. We apply the product and need moisture (rain or irrigation) to break down the granules. But that affects our ability to mow as we don't want to collect the product on the mower rollers or blades. A morning dew can often hinder plans to mow as dew is very sticky and mowing with a surface dew is a sure fire way of picking up that freshly applied fertiliser.

Using mower with no grass boxes to return clippings/fertiliser (above)

So what we do is try to perform late morning/afternoon mowing. The sun is likely to be up by then and maybe some wind will help dry that surface. Once we get weather cooperation, we mow without the grass boxes. In this way, we ensure the product stays on the surface and it's being slowly crushed before it disappears completely. 

Double cut green with better turf density (above)

This week has been one such instance. The greens might have appeared (and putted) wooly/slow. That is the fertiliser breaking down, picking up growth but the unpredictable weather hasn't allowed daily mowing. Either rain or dew have created barriers. They are much further on today (Friday 27 September) than when the fertiliser was applied (Monday 23 September). By next week, it won't be visible.

Hopefully, you're a bit more informed now about fertiliser and turf nutrition!

Enjoy your golf

Ben Allen