Skip to main content

Turfgrass Growth Rates This Spring

Most of you now know that I have been monitoring my growth rates on the course for the past 6 months now. This has been a really enlightening experience and has really opened my eyes to what is really going on with my putting greens. It helps me plan for fertility, keep the greens consistent and also see when the turf is stressed.

The following chart illustrates the growth rate on my putting greens and the effects of plant growth regulators. Prior to the spring growth surge my growth rate was at about 0.4 (This number really doesn't mean anything to anyone but myself. It is based on the clippings we collect on our greens mower each time we cut. It gives us a constant to compare data). In late April the growth rate surged to 2.5 or almost 6x the growth I was seeing in the early spring. After my first application of Primo Maxx at the label rate of 2ml/100m2 the growth rates dropped down to about 1 (our ideal clipping yield based on observed stress and consistency). This growth rate was sustained for about a week when we made our second Primo Maxx application again at the label rate. This application was based on the Growing Degree Day model that can be seen here. After this second application the growth rate continued to drop back down to the levels that we saw in early spring or 6 times less that the late April Growth rates! We wend from cutting every other day back to every 4 days! This is a huge time saver especially when you have a crew of 3!


Now the manufacturers of Primo Maxx and research only claim a 50% reduction in vertical growth. The reason I think that we are seeing the further reduction is the fact that the Poa annua is going to seed. We actually observed the first seed head 2 weeks earlier than normal this year on the 5th of May. When the Poa goes to seed it uses all its energy to produce the seed heads. I think that it is this stress that is causing the growth rate to drop so far down. We also can't forget that the past 3 weeks have been remarkably dry and hot (for West Coast standards) so this could also be a contributing cause of the reduced growth rates.

What I really like about this scenario is that the slowed growth rates we are seeing allow us to keep the greens extremely consistent day to day as well and very fast despite the effects of the seed head on ball roll.  In previous years we normally made our first Primo Maxx application mid-May so we were usually a bit late to really get control of the growth on the putting greens.

Another thing monitoring growth rates shows me is the effects of fertilizer applications. When I saw the first seed heads I upped the N rates by 50% to help replenish the carbohydrate reserves in the stressed Poa. Despite the large increase in fertility the growth rate continued to drop. It is my hope that the plants are using this energy to push through the seed head cycle and remain healthy and strong going into June instead of growing vertically like usual (but who really knows?).

Time will tell if this low growth rate is here to stay or not. I think that by mid June the rates will jump back up into the 1 range when the seed heads finally leave.
Labels:

Popular posts from this blog

Turfgrass speedo is still my most important tool for managing turf growth after 4 years.

It wasn't the easiest year for growing grass , but the conditions were still pretty good. Almost 4 years ago exactly, I came up with the idea of comparing actual clipping yields to the "ideal" clipping yield or the clipping yield adjusted using the Growth Potential Model . Since then, it has proved to be a much more useful tool to manage growth than I originally thought .  It has been almost a decade since I started making observations on plant health and playability and how it relates to the clipping yield. I have been constantly searching for ways to get the growth rate right as often as I can and this tool seems to be the best way I have seen so far, and might ultimately, be the best way going forward. To prove this point I will discuss in a future post, the success I've had with pest control in the past few years (for the most part (Not withstanding the times where I think my greens are dead but they actually aren't...thanks T)). Never needed less There are ...
Read more

Do you have enough?

I recently discussed how we can use fertilizer ratios to simplify how much fertilizer we apply to help us keep above the MLSN guidelines . When we get a soil test done it is a static amount of nutrients found in the soil. Even if you are above the MLSN guidelines at the time of testing, it doesn't guarantee that you will remain at or above the guidelines as the grass grows and consumes nutrients. There is math that you can use to determine exactly how much nutrient you need to apply to ensure that you remain at or above the MLSN guidelines. For many, this is much too complicated. For that reason I made a quick cheat sheet to help you determine how much of each nutrient you can expect to use each year based off a few different annual nitrogen rates. Nutrient use is based primarily on nitrogen use so the left 2 columns are a few different nitrogen rates. The columns for each nutrient are in PPM and are designed to help you look at your current soil test PPM (mehlich 3) and determin...
Read more

How to quantify nutrient content in liquid fertilizer

In a recent post, I discussed how it was actually cheaper to spray soluble vs granular fertilizer. What about if we use pre-mixed liquid fertilizer? How do we even figure out how much nutrient we are applying with pre-mixed liquid fertilizer?  Before I learned that you could simply dissolve soluble fertilizer in water and apply it in a sprayer, I was a big user of pre-mixed liquid fertilizers. One of the issues I initially had was figuring out exactly how much of each nutrient I was applying. The math wasn't as straightforward is it was with granular fertilizers. It turns out, it's actually not that difficult but requires an extra step.  First, we need to convert the liquid volume into a mass. Many products will have the product density displayed on the label or you can look in the Safety Data Sheet (SDS) for that information as well. No SDS? Should you be using products without an SDS? Even if this information isn't included on the label it is very easy to figure out. All ...
Read more