# St. Augustine lawn and Shade



## BakerGreenLawnMaker (Mar 13, 2018)

Hey y'all, I'm new here to the forum and would like your opinion on my St Aug lawn.

I'm from South Carolina about thirty minutes below Charlotte, NC. I love laboring in the lawn, I enjoy seeing the fruits of those labors by the green grass that comes of it. At my old house I took a weed infested yard to a beautifully kept fescue lawn, and I received much of the DYI advice via YouTube. I now live just across town and my lawn is St. Aug mixed with many other species of grass and weeds. Half of my lawn is shaded from two large trees, and you can tell where the shade line starts at, that's where the thickness of the St Aug starts to thin, eventually mixing in with weeds. Last year I didn't do much as far as chemicals because I read that most herbicides will kill the Aug, I put out some 16-25-12 with Mesa and didn't see much of a change to the lawns appearance. I have a few questions; first, what post emergent can I put out that won't kill the St Aug? Second, what's the best fert for St Aug to provoke it to grow in the shaded areas? and third, much like the lawn cultural practices found with Bermuda and Zoysia are there practices similar to those that I could use on the St Aug lawn?


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## Mightyquinn (Jan 31, 2017)

Welcome to TLF!!!

I'm no SA expert but I know that you can use Celsius to kill the majority of your broadleaf and grassy weeds. Not sure on the fertilizer but without a soil test to know what you are deficient in it's up to you to decide what works best. I don't think there is going to be much you can do to get the grass to grow under a tree unless it is getting some decent amount of sun. How much sun do you think those areas get each day? We have a few members here with SA so hopefully they will be by and can give you some more detailed advice


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## Bunnysarefat (May 4, 2017)

The best things you can do to get your St. Augustine to thicken up would be to trim your trees (if possible) and let in some more sunlight. Obviously this is temporary and will have to be done again.

The next thing is to eliminate any competition from weeds with a solid pre emergent schedule. As was mentioned, you can spot spray with Celsius. You can also spray atrazine, I've had decent success spot spraying Atrazine when the weather was mild, very lightly spiked with 2-4D I believe. Atrazine also has pre emergent properties and can be found mixed with fertilizer in "weed and feed" but I don't use those and don't really recommend them. Atrazine is so toxic, even an anti-tree hugger like me has a limit on what kind of pollution and runoff we should accept into our waterways. Use atrazine sparingly and with great care.

When it comes to fertilizer and this grass, I've found less is usually more. It does not respond well to monthly feedings to try and push growth. Never water at night when pushing growth either, only in the mornings. Thickening up under filtered shade takes time but will happen over the course of a full growing season.


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## BakerGreenLawnMaker (Mar 13, 2018)

Mightyquinn, thanks for the advice. It's good to see a fellow 82nd paratrooper on here, I served with the 82nd from 2003-2007 with 3-319th, thanks for your service brother.

The shade isnt so bad that I don't have any St Aug, but it does effect it to where it's not as thick as the front of my lawn. I'd say it gets 4-5 hrs of sun during the peak hours. I need to get a soil test and will check out the Celsius, it's a bit pricey, but I'm sure it's worth it.


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## BakerGreenLawnMaker (Mar 13, 2018)

Bunnysarefat, I had the tree in the front trimmed last year, so hopefully by June I'll see a difference. How often should I put out a pre-emergent? Last season I put out the atrazine a killed the spots, I didn't have it diluted enough obviously, that's why I'm hesitant to mess with Atrazine. As far as the fertilizer goes, should I just feed it in may and let it do it's thing?


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## Bunnysarefat (May 4, 2017)

BakerGreenLawnMaker said:


> Bunnysarefat, I had the tree in the front trimmed last year, so hopefully by June I'll see a difference. How often should I put out a pre-emergent? Last season I put out the atrazine a killed the spots, I didn't have it diluted enough obviously, that's why I'm hesitant to mess with Atrazine. As far as the fertilizer goes, should I just feed it in may and let it do it's thing?


Good call with the atrazine. Use only when really needed. I bought some beginning of last summer and never opened it.

Most guys on here reccomend prodiamine in wettable granular form (Prodiamine 65 WDG) it has a very low cost per application compared to the broadcast spreader type, and has a very long residual, lasting a strong 6 months using at a rate of half of the yearly maximum. Just behind prodiamine is Dithiopyr 40 WSB. Using either of these should knock out 95% of your weeds. Using both probably 99.9% (you can only spray so much per year) obviosly these need a sprayer to apply. There are a few threads on here where the guys geek out on sprayers and calibrating them. It just takes a little planning and practice to do correctly. If you want an easier route, you can go to a box store and get a pre emergent and get better results than nothing. They will sell the kind you spread with a fertilizer spreader, I know I've used one with dithiopyr as an active ingredient and it did great. This route will be much more expensive. To do my entire yard once with box store stuff is about $60, which is the same cost for about ~7 years of prodiamine 65 WDG.. and I know Scott's sells pre emergent but I've never used it. Whatever you do follow the label and do note this needs to be done asap, as it is a bit late to be applying.

For fertilizer, you really have to hold yourself back and feed less than you want to IMO. What I like to do is get two good feedings in before the heat of the summer. Your climate may change this planning a little so it may vary from mine. But once it's really hot outside and temps are not dropping much at night, you should back off on nitrogen. Too much nitrogen and it will be very likely to develop numerous problems like fungus (very annoying) and yellowing. I like to hit it March/April, sometime in June, and then again once or twice in September, and possibly in October. In my yard, I look at the prevalence of grey leaf spot to determine how much nitrogen my grass can handle. No grey leaf spot and I will push it close to 1.0 lb/k, if I see just a little I will go maybe .5 or do organic only. If it's in multiple spots in the yard then no nitrogen whatsoever.

In between those I may use milorganite or some kind of organic supplement to supplement iron mostly. Really helps the color if you can get your soil conditions on point where the iron can be absorb and used by the plant. I had good success with milorganite before they lowered the iron content.

One more tip, keep your mower blade sharp! It makes a huge difference with this grass! And mow high.. I go somewhere between 3.25-4.25 inches.


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## Movingshrub (Jun 12, 2017)

Welcome to the forum!



BakerGreenLawnMaker said:


> first, what post emergent can I put out that won't kill the St Aug?


Prodiamine, pendimethalin, dithiopyr, and indaziflam are all options. Prodiamine is probably your most cost effective option.

If you want some help in identifying which chemicals will play nice with your grass - Univ of TN has a mobile weed manual. You put in what type of grass you have, what you're trying to get rid of, and it will tell you what options you have.

http://www.mobileweedmanual.com/default.aspx



BakerGreenLawnMaker said:


> Second, what's the best fert for St Aug to provoke it to grow in the shaded areas?


No such fert exists. Either make changes such as raising the canopy, removing the trees, or thinning out the trees to allow more light, or switch to a different type of grass.


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## Bunnysarefat (May 4, 2017)

Movingshrub said:


> No such fert exists. Either make changes such as raising the canopy, removing the trees, or thinning out the trees to allow more light, or switch to a different type of grass.


This is true. It's not really the fert that will do this. Only time will allow this grass to spread in thin areas but I've seen it happen in my shaded yard. If you see the runners heading into the thin spots it's working. Water is probably more important than fertilizer in this regard.


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## Mightyquinn (Jan 31, 2017)

BakerGreenLawnMaker said:


> Mightyquinn, thanks for the advice. It's good to see a fellow 82nd paratrooper on here, I served with the 82nd from 2003-2007 with 3-319th, thanks for your service brother.


ATW Brother!!!!!

I was in 1-319th from 2004-2010 I bet we know a lot of the same people :thumbup:

Thank you for YOUR service too and have a fine AIRBORNE day


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## WBrown999 (Apr 3, 2018)

Bunnysarefat said:


> Good call with the atrazine. Use only when really needed. I bought some beginning of last summer and never opened it.
> 
> Most guys on here reccomend prodiamine in wettable granular form (Prodiamine 65 WDG) it has a very low cost per application compared to the broadcast spreader type, and has a very long residual, lasting a strong 6 months using at a rate of half of the yearly maximum. Just behind prodiamine is Dithiopyr 40 WSB. Using either of these should knock out 95% of your weeds. Using both probably 99.9% (you can only spray so much per year) obviosly these need a sprayer to apply. There are a few threads on here where the guys geek out on sprayers and calibrating them. It just takes a little planning and practice to do correctly. If you want an easier route, you can go to a box store and get a pre emergent and get better results than nothing. They will sell the kind you spread with a fertilizer spreader, I know I've used one with dithiopyr as an active ingredient and it did great. This route will be much more expensive. To do my entire yard once with box store stuff is about $60, which is the same cost for about ~7 years of prodiamine 65 WDG.. and I know Scott's sells pre emergent but I've never used it. Whatever you do follow the label and do note this needs to be done asap, as it is a bit late to be applying.
> 
> ...


Wonderful advice my man, thank you. I will be implementing these steps in my yard. Any suggestions are where to buy Prodiamine 65? Haven't been able to source it anywhere in the Houston area. Thanks again.


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## Bunnysarefat (May 4, 2017)

Professional landscape stores like SiteOne might have it, but it's easier to just order online. Just shop around, many of the online carriers also sell on Amazon and it's often free shipping either way.


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## Movingshrub (Jun 12, 2017)

@WBrown999 are you looking for the kind applied with a fertlizer spreader or looking to mix the prodiamine into liquid and then spray the mixed solution?


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## WBrown999 (Apr 3, 2018)

Movingshrub said:


> @WBrown999 are you looking for the kind applied with a fertlizer spreader or looking to mix the prodiamine into liquid and then spray the mixed solution?


Preferably mix+spray -- I have heard it keeps cost per application way down.


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## Movingshrub (Jun 12, 2017)

@WBrown999 - I'd suggest ordering online. I purchased my 5lb tub of prodiamine from  Pestrong.com last year but there are plenty of other places to purchase as well. With that being said, for a 3500 sqft yard, that's going to last you for years. You may consider taking part in a split with someone.


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## WBrown999 (Apr 3, 2018)

Movingshrub said:


> @I'd suggest ordering online. I purchased my 5lb tub of prodiamine from  Pestrong.com last year but there are plenty of other places to purchase as well. With that being said, for a 3500 sqft yard, that's going to last you for years. You may consider taking part in a split with someone.


That's a great idea. @Alan do you have any experience with Prodiamine treatments in our area?


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## Alan (Apr 23, 2017)

I ordered mine online a couple years ago, so I don't recall what site exactly. I failed to put any PreM down this past fall, so I am paying the price with all kinds of crap weeds, most notably spurweed, which if you're not familiar has stickers.


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## c0mical (Apr 8, 2018)

Alan said:


> I ordered mine online a couple years ago, so I don't recall what site exactly. I failed to put any PreM down this past fall, so I am paying the price with all kinds of crap weeds, most notably spurweed, which if you're not familiar has stickers.


Eff, that sounds rough. Are you using a post M to try to remedy the situation?


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## Mowersden (Sep 11, 2020)

Hello all! I just moved into Miami and have a huge lawn in the garden area. I used to live in an apartment before, so I don't know how to manage lawns. Can anyone please suggest what I should do to make laws look healthier and luscious? I am also planning to buy a new mower. Which one is the *best mower for St Augustine Grass*? How much should I water Lawn? Should I hire someone to cut the grass?


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