Wednesday, 27 June 2018


This year I changed my approach to topdressing on my greens. I decided to use clipping volume to determine how much and when I would topdress the greens. The idea is that I will apply sand as the grass grows and hopefully eliminate layering from heavy, infrequent sand applications. My nifty HUD knows how much clippings I have removed from my greens and how much sand I have applied to them. It can then display the sand requirement in a way that makes sense to me.

Sand-O-Meter this morning before applying sand
Sand is applied

Sand-O-meter is automatically updated after I record my sand application into my online records.

I have always guessed at how much sand I need to apply which is a big problem. Sand is now the single most expensive input on my entire golf course and I only apply it on greens! ($2000 in previous years with a target of $500 this year) Just like I was guessing how much I aerify, I decided that if I wanted to refine my sand application practices (and be able to adjust them each year in a meaningful way,) I needed to do better.

Just like with fertilizer, water, and pesticides, no two years are the same for their requirements on your golf course. Using dates on a calendar to schedule maintenance practice such as these just doesn't make sense because Mother Nature doesn't give a shit what day of the month is it. If we want to refine things, we need to base our practices on the actual observed conditions.

a light blow and turn of the heads and they are looking good!
What makes sense to me to base topdressing requirements on is how much growth we have. More growth equals more organic matter production right? I mean, it's probably more complicated than that but in general terms that's kind of how it works.

So after over 6 seasons of collecting and measuring clippings on my greens I have a pretty good idea of how much grass I will harvest. I also have a pretty good idea of how much sand I used to apply.

This is where it gets a bit experimental for me. I'm hoping to reduce thatch accumulation on my greens through careful monitoring of nutrients added vs removed and in theory I hope to keep organic matter production to a minimum but who the hell knows eh?

So, I picked a number that is a lot lower than I have previously applied and will adapt from there. I'm hoping to not have to aerify much or at all so that amount of sand was removed from my numbers. If my chosen annual rate of sand per unit volume of clippings is a bit low, I can adjust it up and if it's a bit high I can adjust it down. In a year where I grow more grass I will automatically apply more sand and in years where there is limited growth I will apply less. Awesome! After a few years I should come to a good number for my course.

The math is simple.

I am applying 227g sand/m^2 per 1g Nitrogen/m^2 removed via clippings. Why this number? I guessed and will adjust it based on soil tests and physical greens properties tests.

To make it more user friendly for me and my staff I converted grams of sand/m^2 into a unit I call "tractor scoops". This is how many scoops are required from the tractor to apply that amount of sand. One hopper in our topdresser holds 2 scoops. Typically a light dusting here will require 4 scoops or 2 hoppers to do. This is an amount that I can apply any day of the week with minimal disruption to golfers but also won't result in me having to apply sand more than once every 3-4 weeks throughout the growing season.

To determine the mass of a scoop of sand you need to first take a scoop of sand with your tractor. Fill a pail with sand and dry the shit out of that sand. Then measure the mass of that pail of sand.

Then see how many pails of sand 1 scoop of your tractor can fill. This entire process took me a half hour. Hint: a tiger torch and a concrete mixer work great for drying sand.

Now you know how much a tractor scoop of dried sand weighs. You also know the volume because you know the volume of that pail right?

For me, one scoop of sand weighs approximately 360 kg when dry.

It is also 228,000 cm^3

1 scoop of sand on 1000m^2 is about 0.23mm thick of sand.

So at the end of the season I will be able to see if that 227g of sand per g of nitrogen removed from clippings is enough and can fine tune my sand applications from there. The ultimate goal is to use as little sand as possible because, hey, it's a non-renewable resource.

Tuesday, 26 June 2018

Growth Rate and Plant Health Hypothetically speaking....

Place looks better in late June that it did in May. Gotta love Junuary!
In my last post I wondered if I could use indicator species to help me grow my grass at the right rate. This is only a hypothesis but is what I have been trying for the past few seasons and it seems to work from what I've seen. Either way, It's not fact and could be total bullshit.

I wonder through, hypothetically speaking, if grass is healthiest (has the least amount of disease) when it's growing at the appropriate speed for the climatic conditions, what are the consequences of, say, using preventative fungicides and growing the grass at the less than optimal rate? (because hypothetically speaking the only way to truly grow the grass at the right speed is by not applying preventative fungicides and seeing the disease)

The more I think about it (if my thinking and observations are true) the only real way to truly achieve the optimal growth rate for plant health (again, less disease) is to use the actual diseases to help you fine tune things. So if this is true (not likely) then what kinds of other issues are we going to get if we mask the diseases with regular fungicide applications?

I'm building hypothesis on top of hypothesis here so this is so far fetched it's not even funny.

Also understand that what I'm trying here is to grow grass without any fungicides, organic or synthetic because I'm not convinced organic is any better than other ways of managing turf. It's all shit! (just kidding)

Is this (sub-optimal growth rate) one of the reasons some people experience major disease outbreaks as the previously applied fungicide wears off?

I know that's probably what I used to observe back when I used a lot of fungicide and had poorly timed fertilizer applications. I applied most of my nitrogen in the spring and fall as the "classic" cool season growth curve suggested I do. I was growing my grass the fastest when my fusarium and growth potential curve were suggesting I grow it slower. In the summer months I was growing the grass slowly when the dollar spot and growth potential curve were suggesting I grow it faster (for my climate anyway). It's no wonder I would get absolutely hammered with disease when I managed my turf this way. I was chasing my tail and putting out fires left and right! Maybe it's not directly a result of the fungicide killing of beneficial organisms as some would suggest, but a combination of that and grass that is growing at the wrong rate. Who the hell knows eh?

The 8th green is growing too slow and has the most dollar spot so I have it some extra nitrogen today.
Dollar spot on the 8th. Interesting how it seems to be on the margin of the bentgrass patch.
It's also no wonder why we had so much poa on our greens because we were constantly killing our grass and the only thing that was saving our ass was the constant supply of poa seed.

What about thatch? Thatch relies on the soil microorganisms to break it down otherwise we are left to physically dilute or remove it through mechanical means. If we are matching growth rates to the soil/plant biology then perhaps we can eliminate or reduce the inevitable organic matter buildup in our soils?

What about plant health in general? The plants ability to be healthy and tolerate traffic and stay nice and dense and competitive? Lucky for me most of our traffic comes at times of the year where growth rates are the highest. It's almost like the ideal conditions for golf are also the ideal conditions for grass growth.

Of course there are going to be times when you need to grow the grass at a rate that will make disease worse. Clubs with high amounts of traffic in the winter months where the grass hardly grows and courses that absolutely need slow growing grass for tournaments in the summer months. I don't think there's any getting around those situations but thankfully most lower end clubs don't have those pressures.

Boy would I love to see some solid research on this.

Clearly I've been thinking too hard.

If you like my blog and want to support what I do you can support me on Patreon or paypal. Thanks!

We have never done less or spent less on our greens

Monday, 25 June 2018

Using indicator species to fine tune fertilizer applications

I get it. I talk a lot about turf disease and fertilizer but it is only because I think that the two things are closely related. More specifically, I think the amount and types of diseases on our grass are closely related to how fast the grass is growing.

Not too shabby
From what I have seen over the past few years of intense growth rate monitoring and reduction in fungicide use is that if we can grow that grass at the right rate, we can reduce the amount of disease significantly.

The trouble is that it isn't that easy to figure out what is the right speed. Further complicating matters is that if you add too much fertilizer, you cannot take it back and are stuck with grass that is either growing too fast which can lead to all sorts of issues at certain times of the year.

I have used the Growth Potential mathematical model to predict nitrogen needs, clipping volume and many other things to try and help me get it right and each year that I further refine my fertilizer timing and rates, the less disease issues I have.

One of the first strategies that I used when starting to really try and reduce my reliance on fungicides was to simply not apply preventative fungicides and use my observations to try and figure out why my grass was diseased. I could never understand why some areas were covered in disease and others were untouched. It started with obvious things like sunlight, drainage and disease spread but then focused on how fast my grass was growing. Grow it too fast and it gets disease, grow it too slow and it gets disease. Grow it just right and there is little or no disease. It sounds too good to be true and it might just be. We have to maintain playing surfaces after all and we can't just grow our grass at speeds to reduce disease. We need to grow it at speeds to manage wear and tear etc.

On a deeper level I think this all ties together with the soil microbiome and that thing called balance we all seek to achieve.

Growing the grass at the right speed isn't that easy because the right speed changes every day! How can we consistently hit this moving target? The mathematical formulas can help but they aren't perfect.

What if I go back to my first disease management strategy and let the disease tell me how much I should fertilize my grass and when and combine these observations with the data collection and growth potential model?

I think it might just work and if you have read some of my recent posts you will know where I'm going with this.

Here are a few of the common turf diseases I deal with and how they can help you refine your fertilizer (and cultural) program and hit that sweet spot with more consistency.

You can further refine things if you fertilize greens individually based on their growth rates and disease levels like I have done for the past year. It's not that hard to do either. Fill up your tank with water with enough to spray all greens. Add the stuff you need to apply to all greens like wetting agents etc. Go spray the greens that don't need any fertilizer. Add some fertilizer. Go spray the greens that need some fertilizer. Add more fertilizer. Go spray the greens that need even more fertilizer.


This disease is mostly a problem in the winter months but I have seen it every month of the year! To me it indicates that the grass is growing too quickly and no additional fertilizer is needed (unless damage is widespread and you need to fill in the dead spots with the aid of a fungicide).

I have noticed that the Smith-Kerns dollar spot model does work for fusarium at some times of the year but I eagerly await the upcoming release of a fusarium specific prediction model to make managing this disease and my plant growth rates that much easier.

Fusarium in June! With elevated growth rates and a brief cool and wet week the disease popped up. Luckily it dried up and warmed up and it went away.

Dollar Spot

This disease is only an issue here in the summer and only on the slowly growing greens. To me dollar spot indicates that the grass is growing too slowly for the conditions and more nitrogen is needed.

The Smith-Kerns dollar spot model is awesome and when I see disease pressure spike I check my clipping volume data to ensure my grass is growing fast enough.

A light spike in disease pressure saw some disease on our greens.

I find that a growth rate of 20ml/m^2 per day is sufficient to manage dollar spot in most cases.


This disease has only become a problem on my greens in recent years I have have consistently reduced my annual nitrogen rates each and every year since 2012. This disease indicates that the grass is growing too slowly and more nitrogen is needed unless you are a sick bastard like me who likes to see the poa die. On our predominantly bentgrass greens I don't adjust the growth rate and just let the poa die.

anthracnose on my first green
As can be seen on the lower chart, my first green has been growing slower than most while receiving the most nitrogen fertilizer to help manage anthracnose on that green.

While still obviously infected (great time to drop some seed), the green is still alive with the additional nitrogen treatments. 


This disease is only an issue in wet summers or if I get lazy and overwater the greens. Dry them out and incorporate some 21-0-0 into your nitrogen fertilizer treatments and it should go away. Needless to say, I haven't seen this disease in years since I stopped being so lazy and started using more 21-0-0.

Brown Patch

This disease used to be a big problem on our greens but we haven't seen it since we stopped watering in the afternoons. Let you grass be dry for as long as possible to keep the humidity down during the heat of the day.


Not a disease but a great indicator species as well. In 2012 our fairways were thatching, soft and didn't drain very well. I decided to try and use less nitrogen to see if we could do something about the thatch. Each and every year I applied less and less fertilizer and the fairways improved more and more until this year when the weeds took over.

What I think happened is that we finally burned up the excess organic matter and now the grass isn't getting enough nitrogen to compete with the weeds. This is a great indication (along with the fantastic drainage and firm conditions) that I need to fertilize my fairways slightly more if I want to keep weeds to a minimum without the need for a herbicide. Even then, the fairways will always be the weakest part of the course until we can renovate them to smooth out the settling that has occurred over the past 30 years.

So while we have a lot of high tech tools available to help us make decisions I think that we can also use turf diseases to do similar things. The diseases are reality and the models are just theory. Ideally we want to prevent the disease in the first place so I still think the high tech tools are essential for keeping things balanced and understanding why the disease is an issue and how you can take action to correct it before it becomes a costly issue. We can use the growth potential model and clipping volume data to get into teh ballpark then if we pay close attention to these diseases (assuming you don't apply preventative fungicides) we should be able to adjust our maintenance practices to hit the sweet spot. And about that playability thing....for me at least, they two things are also closely related. Healthy grass = good surfaces for golf!

If you like my blog and want to support what I do you can support me on Patreon or paypal. Thanks!

Thursday, 14 June 2018

Is Feast or Famine Better than Light and Frequent?

This is what I call "DiseaseyAF" weather
This past week I gave my greens a reasonably heavy fertilizer application (1g n/m^2 (0.25# N/1000) as all the signs I had were suggesting that my greens needed more fertilizer. The poa was thin and weak from just coming out of the seed head flush and was covered in anthracnose.

early signs of anthracnose this past week
I took this opportunity to spread some bentgrass seed as the competition in the next few weeks from the poa will not be very high and this is ideal for seedling establishment.

Not surprisingly, 2 days following the fertilizer application our growth rate skyrocketed and it appears that the anthracnose destruction has slowed which is what I wanted. I want thin, weak poa and the anthracnose is one of the best selective tools (available in Canada eh) I can think of to do that.

A few days following the fertilizer app they are looking much better despite still being covered in disease. F yeah!

While out changing pins today I noticed that the diseased poa was still relatively stunted and slow growing but the bentgrass was surging with growth. I thought that maybe this could be a better way to promote bentgrass over poa annua. Instead of light and frequent feeding we could restrict fertilizer until the poa starts to show signs of stress and disease, throw down some seed, then hit them with a relatively high dose of fertilizer with the hope that the stressed poa cannot take advantage of the increased nitrogen rates as the bentgrass can.

It's just a thought.

We can combine this with measuring the clipping yield and estimating the amount of nutrient removed from clipping removal and adjust our fertilizer rates throughout the year to account of nutrient release from organic matter. This way we can apply relatively high fertilizer rates at some times of the year but also burn organic matter at other times of the year.

While I love the idea of simply applying very little fertilizer like some successful bentgrass growers do. I also think that it might not just be about applying less, but applying the right amount at the right time especially when we take plant health and the desire to use less pesticides into account. From what I have seen and learned over the past few years, we can probably significantly reduce our need for corrective pesticides if we can simply (not that simple) grow the grass at the appropriate speed for the time of year.

My observations about disease and growth rate were reaffirmed this last week when the increased nitrogen rates resulted in an outbreak of fusarium. This was fully expected but also not a worry because the weather next week will be too hot and dry for fusarium to last long. The fusarium is also only present on the poa so any more selective poa death right now is welcome.

Still no fungicides applied since Jan 9 2018. 155 days and counting
It's also worth noting that disease has been so low on my greens that I have dropped phosphite from my disease management program. I have required a fungicide every spring but this year (and last) I made it through without despite applying less and less pest control products. Maybe it's the weather because we had one of the hottest and driest Mays on record.

small patches of fusarium mycelium were visible this morning on the poa. GOOD!

So I think the plan now for fertilizing greens will be to monitor growth rates and poa health and hold off on fertilizer applications long enough to stress the poa and then follow it with a healthy dose of nitrogen to fill in the voids hopefully with bentgrass. Ever since changing the rates and timing of nitrogen on my course (thanks to the growth potential formula) I have made huge gains in bentgrass on our greens. I wonder if taking this a step further by deliberately stressing the poa during the high growth months while also providing the bentgrass with enough nitrogen to remain competitive will be a viable strategy.

There is a lot of talk about how if you want to promote bentgrass over poa you need to use less nitrogen which I think it partially true but like all generalizations I think this idea can be improved upon. While less nitrogen is probably key, bentgrass isn't going to grow quickly enough to fill in the voids if we are trying to convert from poa to bent. Maybe if we can do a bit of both with this approach we will be able to get the advantages of both low fertilizer and high fertilizer rates to achieve our goals of having more bentgrass?

There's only one way to find out I guess.

This is, of course, subject to constant change.

If you like my blog and want to support what I do you can support me on Patreon or paypal. Thanks!

Monday, 11 June 2018

If I had a magic 8 ball

It would probably read,

"All signs point to fertilizing more!"


Despite my lack of a magic 8 ball I do have the next best thing. A HUD (Heads Up Display) which shows all my course data. This is supposed to help me make better decisions by automatically analyzing the data I collect and presenting it in a single place for my observation.

When I combine what the HUD is showing me with my disease observations it becomes clear what I should do and what I should do is fertilize my greens more. You might be thinking what's the big deal, just apply the fertilizer already you asshole! You are probably right but the reason I am so hesitant to apply fertilizer is that once you apply it, you can't take it back. As fertilizer has such a big impact on turf conditions and the costs associated with maintaining the golf course I need to be absolutely certain that the fertilizer is needed. So far this year we have mowed less than ever before. This has big impacts on fuel use, mower wear and tear and labor required to maintain the course. Growing the grass faster than absolutely necessary just wastes money.

1. Greens are lean

So far this year we have only applied 2.9 grams of nitrogen per square meter on our greens (0.64# N/1000). Through the measurement of our clipping volume I have been able to watch how much nutrients we are removing from our greens and compare that to how much we have applied.

In the last month we have removed more nutrients from our greens that we added. It's obvious from the chart below and it's also obvious with how visible the #friskyfairyring is on the greens. Bottom line, they are lean!

This fairy ring has never been visible on our greens. Bottom line, they are lean AF right now.
Wow, those greens sure are lean. Don't need a stupid graph to tell you that!

I know, I know, but having the data helps me understand how lean they are and why. In this case they are lean because we have applied less nutrient than we removed in the last month.

2. Disease

This week anthracnose showed up on our poa. For most of my greens there isn't much poa so I can let it die a quick and painful death. My first green is still mostly poa so I need to slow the death down to a level that will see the surface covered in turfgrass while the recently seeded bentgrass has a chance to fill in the gaps left behind by the disease and poa seed head.

anthracnose is back and by the looks of it, widespread

bentgrass seeded into the voids left behind from the poa seed head and anthracnose

The BMP guide from Rutgers suggests that increasing nitrogen rates will lessen the impacts of anthracnose among other things. My goal is not to eliminate the anthracnose but to slow its destructive tendencies down a bit. Anthracnose is a great selective pathogen that will kill out the poa and leave the bentgrass relatively unscathed.

So the increased nitrogen rates are double beneficial for dealing with anthracnose. They slow the disease down and hopefully help the bentgrass fill in the voids a bit quicker. I applied 1g of nitrogen per square meter to our first green which is the hardest hit with anthracnose for a cost of $2 this week. As time goes on I will continue to add these relatively heavy fertilizer apps to manage the anthracnose on this green and others as required.

Growing the grass at an increased rate in the summer is also a good strategy for dollar spot and is one of the principle strategies employed at the Vineyard Club. This week we had dollar spot show up on our greens and not surprisingly our growth rates are well below that where I have observed are good for managing dollar spot.

Dollar Spot is back. F sake
Growth rates are currently below the dollar spot target

There was a spike in disease pressure yesterday. The DS action threshold is probably set too high btw.
Despite the high disease pressure last month, the increased growth rates were enough to keep the disease away.
So there you have it. Growing the grass faster than we currently are will help reduce disease. Why don't I just apply a fungicide? Well a fungicide costs about $600+ where increasing fertilizer will cost maybe $10. It just doesn't make sense to run to a fungicide (yet) when I clearly have options that are much cheaper and probably (hopefully) just as effective.

3. Greens are too fast

Our green speeds are too fast which isn't a bad problem if you are a good golfer. Our course is difficult enough and as we approach the busy season where there are many novice golfers playing we need to keep our green speeds down to keep the time it takes per round down. No one likes a 5 hour round. Either way, we can stand to have them slow down a bit without worrying about them being too slow.

Greens speeds are the high. Note the dip in speeds during the effing poa seed head flush.

The sure are fast downhill these days

So there you go. This is just one example of how I am using my HUD and the data collection to make better decisions (hopefully) about how we grow our grass.

If you like my blog and want to support what I do you can support me on Patreon or paypal. Thanks!