PGR Tracker
See when each growth regulator, feed, hardener or fungicide runs out — timed on degree days or growth potential from your own weather — and when to spray again
On this page
The PGR Tracker tells you when a spray has stopped working and when to go again, counted from your own weather rather than a fixed number of days.
Open Course › Turf & growth › PGR Tracker. It needs Premium.
Two ways TurfWise times a re-spray
The card at the top, Two ways TurfWise times a re-spray, explains the two counts the page runs on.
Degree days — for growth regulators
Counts heat. Every day adds its average temperature above 6 °C: a 10 °C day adds 4, a 20 °C day adds 14. The hotter it gets, the faster a growth regulator wears off, up to 30 °C. The worked example is Primo Maxx (trinexapac-ethyl): spray again at 150 degree days — about 38 days at a steady 10 °C, or 11 days at 20 °C.
150 or 140?
150 is the figure Syngenta quote for Primo Maxx II on a base-6 count. On some courses — different turf, soil or management — 140 works better. You can change the target on any tracked spray, so try it against your own greens.
Trimmit or Anuew in the tank?
TurfWise has no re-spray figure for paclobutrazol (Trimmit) or prohexadione (Anuew), so it won't guess one. When you log the spray, choose degree days and type your own target — it's tracked from there.
Why base 6 °C?
Below about 6 °C the grass is barely growing, so those days don't count. It's the base Mark Hunt uses, and the same one Syngenta's GreenCast degree-day figures run on — so your numbers line up with theirs.
Growth potential — for feeds, hardeners and fungicides
Counts how hard the grass is growing. An ideal growing day — an 18 °C average — adds about 1. Cold days add very little, and so do very hot ones, because the grass slows down in a heatwave too. The TurfWise house figure is to spray again at 9.5 — about 10 days at a steady 18 °C, about four weeks at 10 °C.
TurfWise uses 18 °C as the ideal temperature, the UK-adjusted figure Mark Hunt pioneered, rather than the 20 °C global figure. It tracks British grass more realistically.
The same day, counted both ways then shows an 8 °C, 18 °C and 30 °C day on each count.
Tank mixes and the Growth page
A spray with a growth regulator in it is timed on degree days, even in a tank mix. Growth potential here isn't the same figure as Growth on the Course hub, which also allows for daylength and season.
What am I looking at in the two sections?
Two sections follow: Growth regulators · degree days and Feeds, hardeners & fungicides · growth potential. Each shows how many sprays are being tracked, the Next date and how many have Run out.
Every tracked spray gets a row with the area, the products, a progress bar — 80 of 150 degree days, say — and the Spray again date. The status pill tells you where it stands:
- Still working
- Due soon — most of the way there
- Spray now
- Run out — the bar turns red and the date reads Ran out
Rows are sorted soonest to run out first, and anything due or run out also shows on Today.
How do I start tracking a spray?
Growth regulators logged in Spray & Fertiliser start tracking on their own. For anything else:
Click Track a spray
It's at the top of the page. Pick the spray from the list of completed applications.
Choose what the interval follows
Under Interval follows, pick Growth potential, Degree days or Days. For a feed or fungicide, TurfWise suggests a growth potential target when it recognises the product.
Set the number and start
Type the figure in Reapply at and click Start tracking.
Missed some?
Find untracked sprays looks through your completed sprays for growth regulators and fungicides that were never tracked and starts them for you.
What do I do when I've sprayed again?
Click Sprayed again on the row and the count starts afresh. The ··· menu on each row has two more options: Change when to spray again to edit the target, and Stop tracking to drop the row.