What are the risks?
PrimoMaxx has been around for a long time now so we have a pretty good understanding the way the product works.
High dose rates generally result in a higher levels of Phytotoxity (yellowing of the leaf) which is usually negated by the addition of Nitrogen and/or Iron.
Of course there is always a risk but even the worst case, extreme over applications I have witnessed has only resulted in severe yellowing of the turf and prolonged period suppressed growth rather than plant die-back.
What should I tank mix with it?
This is where the normal advice goes out the window for me.
Normally I'd say small amounts of N and Iron will negate the yellowing that you can see from higher rates or applying to less than perfect turf. However if we're purely looking to minimise clipping yield then I'd drop the fertiliser out of the program and if colour is a concern then rely on a pigment in key areas to maintain turf colour.
Since most people I've spoken to are purely looking for growth suppression and this isn't about short term putting surface quality I'd probably leave the Fe out too. For pure growth regulation, the two things you are in control of are N input and PGR input. So the answer here will be dependent on where you are with your feed program at the moment.
When should I start?
Normally we'd say hang on until soil and air temps average around 8-10C for extended periods of time. But given the circumstances - I'd say if you're prepared to accept a little bit of yellowing - go as soon as you need to. The good news is that the temperatures are currently low so longevity should be really good at this time of year.
When will I need to apply again?
As mentioned earlier longevity isn't heavily impacted by rate but clipping reduction definitely is. Lots of work done on GDD and 150 GDD (base temp 6c) or 200GDD (base temp 0c) is a pretty good bet. Again the good news is that the temperatures are currently low so longevity should be good at this time of year.
In real terms that could be:
- April 3 - 6 weeks
- May 3 - 4 weeks
- June 2 - 3 weeks
After that re-application will be required to ensure you keep a lid on growth.
If you really want to suppression of growth on greens then you'll need to utilise the 0.4L/Ha rate on a that 7 day window. Use the 7 day interval to help you control growth rather than the rate.
Find out about the legalities of using Primo Maxx here.
And to find out about how much Primo Maxx to use and for how long - click here