# KBG reno: when to change irrigation schedule



## vnephologist (Aug 4, 2017)

Question up front, further explanation below: How long past seed down are folks usually switching over to infrequent deep watering?

I renovated last Fall with a mix of KBG & hybrid cultivars (Barvette, Barduke, Barrari, Everglade, Midnight, Award, NuGlade, Keeneland, SPF30). July & Aug's heat really hurt some areas so I'm planning to completely renovate or PGR & slit overseed with the Barvette HGT mix and Mazama this Fall. In preparation, I started thatch raking (by hand) this weekend and noticed that in several of the most dormant areas I actually pulled up entire bunches of sod. There was an immense amount of root mass for about 1" of soil, with hardly any deeper roots. I water deeply as needed using a Rachio controller (usually 1-2 times per week). This has me wondering if perhaps I should change my irrigation schedule for the renovation this year. At seed down, I watered for only a few minutes 4-5 times per day depending on temp. This worked really well for germination. I don't exactly remember when I changed the watering schedule away from that, but perhaps it was too late?


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## Ridgerunner (May 16, 2017)

I have found that within the first year or two after seeding KBG, the turf is particular susceptible to temperature and moisture levels (drought stress and also disease). Much more so than older established turf. Most likely this is primarily due to the newer turf still developing a robust root system. Not a very satisfying answer, but a careful eye and quick response to the turf needs, rather than a formulated schedule is the best I can advise regarding a watering regimen. 
I'm more concerned as to why raking the dead areas was pulling up chunks of sod. That condition is commonly (but certainly not always) associated with insect (e.g. grub, etc) or root disease. Prior to beginning re-seeding, I would recommend you do your best to determine the possible presence of those two possibilities and take (or be prepared to take)remedial action.


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## vnephologist (Aug 4, 2017)

Ridgerunner said:


> I have found that within the first year or two after seeding KBG, the turf is particular susceptible to temperature and moisture levels (drought stress and also disease). Much more so than older established turf. Most likely this is primarily due to the newer turf still developing a robust root system. Not a very satisfying answer, but a careful eye and quick response to the turf needs, rather than a formulated schedule is the best I can advise regarding a watering regimen.
> I'm more concerned as to why raking the dead areas was pulling up chunks of sod. That condition is commonly (but certainly not always) associated with insect (e.g. grub, etc) or root disease. Prior to beginning re-seeding, I would recommend you do your best to determine the possible presence of those two possibilities and take (or be prepared to take)remedial action.


It only came up where there were completely dead/dormant patches. There seemed to still be what looked like peat moss still in that layer (I top dressed during reno). I might dig a bit deeper in those sections and check the state of the soil below. It seems like the root mass just developed in the layer of peat moss for some reason. I'll also grab some pics.


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## social port (Jun 19, 2017)

Grubs/ insects was my first thought as well.

If you are going back out to investigate, I recommend taking a long screwdriver with you to see if there are buried rocks or if the soil is highly compacted.


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## vnephologist (Aug 4, 2017)

social port said:


> Grubs/ insects was my first thought as well.
> 
> If you are going back out to investigate, I recommend taking a long screwdriver with you to see if there are buried rocks or if the soil is highly compacted.


Since a couple of the spots are already completely bare, I thought I might just take a metal pipe or bulb planter to grab a full soil profile.


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## Ridgerunner (May 16, 2017)

A detailed description of the steps you used during the seeding may help too. Typically, topdressing seed involves applying 1/4" or less of dry peat moss. Did the roots primarily developed in that thin layer or did you apply significantly more, or possibly "till" peat moss into the top layer of soil prior to seeding? Would you describe the root mass as "thatch-like"?


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## social port (Jun 19, 2017)

vnephologist said:


> social port said:
> 
> 
> > Grubs/ insects was my first thought as well.
> ...


 Do yo thang :thumbup:


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## vnephologist (Aug 4, 2017)

Ridgerunner said:


> A detailed description of the steps you used during the seeding may help too. Typically, topdressing seed involves applying 1/4" or less of dry peat moss. Did the roots primarily developed in that thin layer or did you apply significantly more, or possibly "till" peat moss into the top layer of soil prior to seeding? Would you describe the root mass as "thatch-like"?


I jumped back to my renovation thread over at ATY to refresh my own memory. There was some confusion about the amount of peat moss, but it was 38cu/ft over 2.5k. I'd say 1/4" or less, or at least that was my intention. I didn't do any tilling, but did core aerate and use a dethatching blade on my push mower prior to seed down. I guess you could describe the area as "thatch-like," but it seemed kind of like a mix of peat with mass of tiny roots. PIcs will help. Coming soon...


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## vnephologist (Aug 4, 2017)

So I didn't get a chance to dig deeper, but I did pull up another piece from the spot I tore up yesterday. The first few pics were as it was when I pulled up, then the last few after I knocked some of the dirt out. I dug around a bit in the divot with my hand after pulling it up and there are definitely a few roots in there, but not nearly the mass that's in the hunk I pulled up.


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## GrassDaddy (Mar 21, 2017)

I'm seeing green in that chunk.. could it be the new grass just needs more water? This first summer I have been watering 1in twice a week and it thrived. Even if it is patchy you can get KBG to fill in with aggressive N.


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## vnephologist (Aug 4, 2017)

GrassDaddy said:


> I'm seeing green in that chunk.. could it be the new grass just needs more water? This first summer I have been watering 1in twice a week and it thrived. Even if it is patchy you can get KBG to fill in with aggressive N.


It's totally possible that what's there is just mostly dormant because of the heat, but it still seems odd that the roots aren't any deeper, no?


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## Ridgerunner (May 16, 2017)

The roots are a bit more shallow than desired, but that;s not so unusual for a last Fall reno and KBG in general. That will make watering critical in avoiding dormancy and eventual death of KBG if water is not timely provided. Soil looks good from a tilth perspective. In fact, your soil may be so loose that it allows the turf to tear up easily. I don't see any obvious signs of a root disease or insect damage. It's possible that it's dormant. You can hope. Check the crowns and see if they are still alive. Nothing really stands out except: Based on the pictures, for example the third one, there appears to be lesions/blotches present on some of the blades. Disease could definitely be a likely culprit or the final nail when coupled with drought stress..
Whichever the case, it's a bit late now to do much of anything. See if it recovers as temperatures fall and moisture returns and over-seed to repair.


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## g-man (Jun 15, 2017)

So I read your ATY post and this one. I did notice one thing. Very large trees with a lot of shade. Could you describe how much sun this kbg lawn is getting? Do you have a log of what you applied in terms of nitrogen sine the reno?

Also, what was your irrigation scheme for this year? Like how much / how long you watered.


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## vnephologist (Aug 4, 2017)

g-man said:


> So I read your ATY post and this one. I did notice one thing. Very large trees with a lot of shade. Could you describe how much sun this kbg lawn is getting? Do you have a log of what you applied in terms of nitrogen sine the reno?
> 
> Also, what was your irrigation scheme for this year? Like how much / how long you watered.


First, for irrigation. Since late Fall after 8 minutes 4-5x daily for seeding, its completely controlled by my Rachio controller based on ET rate from my onsite weather station and an estimated root depth. I think this is where I messed up. In looking back through the watering history it looks like for most of the Winter and early Spring, it was watering ~0.25" ever other day. I think the frequency was the result of my root depth setting of 2" (now seems like I trained it shallow!). Then in May, I modified the root depth to 6" and it looks like it was watering ~0.5" twice a week. The unshaded area near the road is getting a bit more and the more shady region a bit less. Changes to the schedule based on rainfall as well. My soil sample from this thread is from the sunny area. Perhaps I'll compare to the more shady (and healthier) area too. My thought is that after seeding this Fall, I should go ahead and change the root depth to 6" for longer with much less frequency. I'm still wondering how long I should wait after seed down to make this change though.

We're a bit off-topic, but this is also great! Please provide any feedback based on what you see below. 
I had been keeping an accurate journal starting in the Spring, but I went back and added as many details as I could remember and gather from my posts for the Fall. Here are my thoughts... My preventative fungicide treatments have been way too low. I think I had thought the Serenade directions were based on cap and not cup. Other than a small Pythium breakout that I nuked quickly with Pillar G in May, I never saw any signs of obvious fungal breakout like I have in the past. The other thing that stands out to me now and based on some of my older pictures is that my N application was probably too low. I think most of the green I lost in the Spring was probably more due to lack of N than temps. We had a mild winter and I never saw top growth stop. I also realize that I would've been better off starting PGR much earlier, but I just discovered it after investigating ways to enhance the genetic color of my HGT KBG blend. It has definitely worked for that. Its also possible that some of these spots got a very ill timed spot spray of MCPA, Mecoprop-p, Dicamba and Carfentrazone to kill some clover back in June.


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## g-man (Jun 15, 2017)

Thanks for the log. That helps access it in detail. I'm going to start by saying that I'm not a transition lawn guy. Virginiagal could lend some of her experiences with your weather far better than I can. Universities in the transition zone also share a lot of their recommendations. CCM241 shared this one from NC State: https://content.ces.ncsu.edu/tall-fescue-and-kentucky-bluegrass-home-lawn-calendar

Since you asked for feedback, I did noticed a few things that I dont think are best practices. The 0.5 lb N/k of urea right after the first mow. This pushes top growth at the sacrifice of root growth. After that it starved until April 2017. I would recommend something like 0.25lb N/k a month after the first mow and then continue around once a month when it is actively growing. I due agree with your assessment that spring was low on nitrogen for a new kbg lawn.

PGR - I'm not sure if I would use it in a new lawn. Pete1313 or ericgautier might share their opinions in this subject.

Lastly, the green max in the early of july. Pushing nitrogen in the heat of summer in the transition zone, is dangerous since you will need to irrigate more thus leading to more fungus. Also the lawn is in survival mode and nitrogen will push it to grow.

Now to the rachio. I would leave it at root depth of 6in all the time. I leave mine at 6in with 0.8 crop coefficient. I would switch the allow depletion to 70% for a young lawn and dial it back to 50% after 3-4 months. Why? You want to keep the 6in in the proper moisture so the roots have water in that depth. A young lawn doesnt handle dry conditions, so the allow depletion will make sure that is kept with good moisture.

So lets make lemonade. I would follow a transition zone fertilization program. KBG will respond to it. Tweak your rachio to promote deep and infrequent watering.


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## vnephologist (Aug 4, 2017)

Thanks for the sage advice g-man. I think this all makes sense. Particularly on the Rachio. Not sure why those settings hadn't occurred to me. At this point I need to decide whether to attempt and overseed with PGR or just go for a reno. At this point I'm leaning towards both.  Maybe an overseed in the shadier areas that have held up well and a reno in the strip by the road that's taken a beating. Either way, I think I'll lay out a firm plan and start a thread for comment. Maybe I'll post some pics tomorrow for folks to weigh in based on current condition. Thanks again!


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## vnephologist (Aug 4, 2017)

So I spent a few hours and got a lot more dead stuff off today. Made some interesting discoveries. I'll start with a pic of the worst damaged area (dog urine & ill timed herbicide).

Kill it off and start over?...


Here's a good pic of the more healthy part of the lawn before and after the thatch rake...


The thatch rake turned up a few Fescue clumps that were matted down. I guess the PGR has less effect on them because once I raked, the were much taller and stuck out like sore thumb. Interestingly, almost every singe one had fungus damage. The KBG around them was more less unaffected. Gray leaf spot maybe?...


Found this guy. Not a grub, right? More like a caterpillar?


This is probably the most relevant pic to the original thread purpose. I think it shows more of what I was talking about. This was a spot with completely dead/dormant grass above. As I started pulling it out, the turf gave way and you can see under. See how there's a layer of small intense roots? Interestingly, there were some nice looking rhizomes under there with a few emerging tillers. I know I need to modify my watering, but I'm starting to wonder if a lot of these spots would repair themselves this Fall...


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## J_nick (Jan 28, 2017)

I remember reading somewhere that properly fertilized KBG will spread 1 sqft a year.


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## Ridgerunner (May 16, 2017)

I'd never suggest starting over with that much good turf established with nearly no weeds. Overseed this Fall and next Spring, promote root growth and spreading by spoon feeding while soil temps are below 70.


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## g-man (Jun 15, 2017)

^ agree

Plus you don't even need to overseed. That's kbg, it will spread with proper fertilization and watering.


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