Primo Maxx FAQ 2023

Primo Maxx is one of Syngenta's most talked about turf products, we get asked, and answer a lot of questions on it every year. It's a product that has huge potential to improve plant health when used correctly and the added extra of helping you deliver fantastic playing surfaces!

What is it?

Primo (Primo Maxx II) works by suppressing gibberellic acid, the hormone responsible for vertical growth in turf plants.

The more product in the plant, the greater the suppression. Gibberellic acid is kind of like growth hormone for us humans, when conditions are right the plant shoots up in height

(but the plant doesn’t get a deeper voice and mood swings to go with that vertical growth).


When to start Primo applications?

When you get consistent growing temperatures!


What rate should I go at?

It depends where your spraying. Rates vary for different grass types and heights of cut. But we would generally advise going half rate for the very first application of the season.

For greens for example:

The bottom line here is related to water rate. Primo wants to be available to the foliage and crown not the roots so we are targeting a foliar application. Ideally using a purple or red nozzles to get the right droplet size to leave that product on the leaf and avoid runoff.

It only needs an hour on the leaf before its rainfast, which works out well for UK & Ireland weather patterns, and allows it to fit in with irrigation cycles in the summer.

What benefits does it give?

There are many benefits to building a primo program. Its a product that’s popular here but also hugely popular in the US. Meaning we have literally decades of data to support its performance in a huge array of different areas.

In terms of performance benefits you can expect:

All those benefits really link back to the way the product works, energy diverted from vertical growth into lateral growth and rooting.

It sounds too simple, but a plant with a better established root system is better able to uptake nutrients and moisture.

When we are able to bring down clipping yields we leave the plant more of the leaf tissue it has painstakingly created, so it doesn’t need to replace what has been lost as urgently.


Something that we haven’t spoken about so much in the past are its benefits in terms of cost/labour saving, and savings in terms of CO2 emissions.

The figures quoted can be taken with a pinch of sugar (is that the opposite of salt?), since all the costs involved have gone up since the study was published, fuel and machinery increasing significanly in the last few years.

There really has never been a better time to use Primo!

How long between sprays?

For any Matrix fans, this is very much the difference between the red and blue pills.

You can get fairly good results with the “blue pill

Simple, classic:

  • Cool weather – every 4 weeks
  • Warm weather – every 2 weeks
  • In the middle – In the middle

But for those who wanted the red pill before I even listed it, its GDD for you.

GDD (Growing Degree Days) is a great tool to track grass growth. Its simply using temperature. The colder it is the less the grass will grow and the warmer the more growth.

It really just formalises what turf managers are feeling “Its warm today” but that doesn’t tell us if it stayed warm all day, or if it was warm at night etc. Its going to give you more accuracy than the first method especially at changeable times.

No system is perfect but with GDD you can get fairly close.

We’ve got a few blogs on GDD so I won’t go deep into that now.

You can always check the GDD tool on the Syngenta turf website, but excitingly we’ll have it featured in the new weather app when that’s launched to make it easier to check on the go.


What are the downsides to using Primo?

I’ve touch one one already, people have sometimes reported slight yellowing after the first application of the season, but this is generally negated if you include a little foliar nutrition with the spray.

It gets ‘hooky’. Not that many do, but its probably hard to come off primo once the benefits have kicked in. For most it becomes a solid part of the turf management strategy.


Here’s a younger Dan talking about Primo in his own words.

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