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Help Interpreting Soil Test

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LAlawnnut
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Help Interpreting Soil Test

Post by LAlawnnut » Wed Feb 13, 2019 10:36 am

Hey guys,

Below are my soil tests for my roughly 8k sq ft yard I’m working on. I found a feed store with pelletized lime so I am going to put that down at their recommended rate to help the PH. I am looking for help with the rest. It seems I need a ton of N and I’m not sure what the most cost effective way to get that much N down is, and if I should go ahead and do it all now. I also need recommendations for the P and K portion, as I’m having trouble figuring out what products to use to raise those. Is there anything else I need besides those above?


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Re: Help Interpreting Soil Test

Post by pennstater2005 » Wed Feb 13, 2019 10:44 am

@LAlawnnut I moved this into the Soil Fertility subforum for more eyes on it. And welcome to TLF!!!
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Re: Help Interpreting Soil Test

Post by iowa jim » Wed Feb 13, 2019 11:33 am

These recommendations are for the whole year and not to be applied all at one time. Im not a soil expert but there should be somebody coming along to help you out.

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Re: Help Interpreting Soil Test

Post by LAlawnnut » Thu Feb 14, 2019 6:34 am

Morning bump. Anyone got any recommendations to fix the soil

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Re: Help Interpreting Soil Test

Post by g-man » Thu Feb 14, 2019 7:28 am

St. Augustine has very different requirements than Bermuda. Which one you think you have or want to dominate?

The pH is low for Bermuda, but i think it is fine for st. Augustine. If you want Bermuda, then you need to add lime.

Phosphorus is very low at 4ppm. But again, st. likes a low phosphorus.

K is a also low.

In your first table the list some of the products they recommends. For phosphorus, TSP (triple super phosphate). For potassium, they recommend MOP(0-0-60), but I would advice trying to find SOP (0-0-50).

For nitrogen, I recommend following the Bermuda Bible for Bermuda. Urea is the cheapest source of nitrogen. For st. Augustine, it doesn't t like too much nitrogen, 1-2lb of N/ksqft for the entire year.

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Re: Help Interpreting Soil Test

Post by jdc_lawnguy » Thu Feb 14, 2019 7:57 am

@LAlawnnut Welcome to TLF.

I am not an soil nutrient expert, but I am going through the same thing so let me share some knowledge I have recently gained.

Your recommendations above are to be spread across the year.

The recommendations are a little confusing in my opinion looking at them as a newbie with fresh eyes. But let’s break them down. I have picked 1 product per nutrient to use as an example.

Nitrogen = N
9.9 #’s of Urea
Urea is 46% Nitrogeen
9.9 x 0.46 = 4.5 #’s of Nitrogren per 1000 sq/ft
1000 sq/ft is commonly referred to as M
So we have 4.5#’s/M

Phosphorous = P
Triple Super Phosphate is 46% P
6.16 x 0.46 = 2.83 #/M

Potassium = K
Muriate of Potasium is 62% K
4.74 x 0.62 = 2.93#/M

So what your results tell you is you want to put down

NPK at a round rounded ratio somewhere in the area of 4/3/3. You might not find the perfect balance but you will find something close. But what is important is you put down something that contains Each element and the N should be the highest number.

Looking at some common fertilizers I see siteone sells a 12/8/8 which is close to the ratio you are looking for. Note unless you are going liquid and custom blending you may not find exactly what you are looking for.

But let’s take this a few more steps.

You need to put down ~4.5#N/M. If you divide that over say 6 apps you are going to want to target ~.75 #N/M per app

Since the fert is 12% N you divide your target N by N to get the number of pounds you need /M to get .75N

0.75/.12=6.3lbs/M of fert

With a yard that is 8/M you would put down 1 50 lb (6.3 x 8 = 50.6) bag per application.

This would give you ~0.75N, 0.5P, 0.5K per feeding

Over the course of 6 applications you would put down the following
4.5N
3K
3P

Now, I used 6 feeding because I knew it would make the math easier and use a 50# bag per feeding but you can tweak it as need. Just don’t add it all at once. 😀

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Re: Help Interpreting Soil Test

Post by LAlawnnut » Fri Feb 15, 2019 8:00 am

g-man wrote:
Thu Feb 14, 2019 7:28 am
St. Augustine has very different requirements than Bermuda. Which you think you have or want to dominate?

The pH is low for Bermuda, but i think it is fine for st. Augustine. If you want Bermuda, then you need to add lime.

Phosphorus is very low at 4ppm. But again, st. likes a low phosphorus.

K is a also low.

In your first table the list some of the products they recommends. For phosphorus, TSP (triple super phosphate). For potassium, they recommend MOP(0-0-60), but I would advice trying to find SOP (0-0-50).

For nitrogen, I recommend following the Bermuda Bible for Bermuda. Urea is the cheapest source of nitrogen. For st. Augustine, it doesn't t like too much nitrogen, 1-2lb of N/ksqft for the entire year.
Thank you for the help. I think I have more Bermuda so I will probably just let that take over. I may be wrong and it was hard to tell last year given the poor soil and amount of weeds. Hopefully this year I will get it under control. I should be throwing out lime this weekend

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Re: Help Interpreting Soil Test

Post by LAlawnnut » Fri Feb 15, 2019 8:26 am

jdc_lawnguy wrote:
Thu Feb 14, 2019 7:57 am
@LAlawnnut Welcome to TLF.

I am not an soil nutrient expert, but I am going through the same thing so let me share some knowledge I have recently gained.

Your recommendations above are to be spread across the year.

The recommendations are a little confusing in my opinion looking at them as a newbie with fresh eyes. But let’s break them down. I have picked 1 product per nutrient to use as an example.

Nitrogen = N
9.9 #’s of Urea
Urea is 46% Nitrogeen
9.9 x 0.46 = 4.5 #’s of Nitrogren per 1000 sq/ft
1000 sq/ft is commonly referred to as M
So we have 4.5#’s/M

Phosphorous = P
Triple Super Phosphate is 46% P
6.16 x 0.46 = 2.83 #/M

Potassium = K
Muriate of Potasium is 62% K
4.74 x 0.62 = 2.93#/M

So what your results tell you is you want to put down

NPK at a round rounded ratio somewhere in the area of 4/3/3. You might not find the perfect balance but you will find something close. But what is important is you put down something that contains Each element and the N should be the highest number.

Looking at some common fertilizers I see siteone sells a 12/8/8 which is close to the ratio you are looking for. Note unless you are going liquid and custom blending you may not find exactly what you are looking for.

But let’s take this a few more steps.

You need to put down ~4.5#N/M. If you divide that over say 6 apps you are going to want to target ~.75 #N/M per app

Since the fert is 12% N you divide your target N by N to get the number of pounds you need /M to get .75N

0.75/.12=6.3lbs/M of fert

With a yard that is 8/M you would put down 1 50 lb (6.3 x 8 = 50.6) bag per application.

This would give you ~0.75N, 0.5P, 0.5K per feeding

Over the course of 6 applications you would put down the following
4.5N
3K
3P

Now, I used 6 feeding because I knew it would make the math easier and use a 50# bag per feeding but you can tweak it as need. Just don’t add it all at once. 😀
Thanks man I appreciate all the knowledge. I was calculating that I needed 21 pounds of nitrogen so I calculated base on the bag and was thinking I needed a few hundred dollars in fertilizer. You made me feel much better lol

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Re: Help Interpreting Soil Test

Post by SCGrassMan » Fri Feb 15, 2019 9:19 am

Lots of lime. Your pH is super low.
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Re: Help Interpreting Soil Test

Post by LAlawnnut » Fri Feb 15, 2019 11:03 am

SCGrassMan wrote:
Fri Feb 15, 2019 9:19 am
Lots of lime. Your pH is super low.
They recommended 4.59 per 100 sq ft so roughly 46/M. Is it okay to put it all down now at once?

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Re: Help Interpreting Soil Test

Post by SCGrassMan » Fri Feb 15, 2019 12:29 pm

I don’t think so. I’d go like 10-20lbs.
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Re: Help Interpreting Soil Test

Post by LAlawnnut » Fri Feb 15, 2019 12:52 pm

SCGrassMan wrote:
Fri Feb 15, 2019 12:29 pm
I don’t think so. I’d go like 10-20lbs.
So put down maybe half now and half in the fall?

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Re: Help Interpreting Soil Test

Post by g-man » Fri Feb 15, 2019 1:12 pm

50lb/M of ag lime are safe in a single application and every 6 months.

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Re: Help Interpreting Soil Test

Post by LAlawnnut » Fri Feb 15, 2019 1:45 pm

g-man wrote:
Fri Feb 15, 2019 1:12 pm
50lb/M of ag lime are safe in a single application and every 6 months.
Based on your experience if I put down 50lb/M right now how long would it take to change the PH, and when should I get another soil test to see where I’m sitting?

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Re: Help Interpreting Soil Test

Post by g-man » Fri Feb 15, 2019 2:18 pm

It takes a long time. This is a marathon, not a 100 meter race. Apply the lime per the test recommendations and test next year around this timeframe.

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Re: Help Interpreting Soil Test

Post by Ridgerunner » Fri Feb 15, 2019 4:48 pm

Normally, I wouldn't suggested adjusting Mg levels. Seeing as you need lime, you might consider using some dolomitic lime to bring Mg up a touch. I'd suggest no more than 10 lbs of dolomitic per thousand square feet. That could raise Mg levels by 26 ppm if Mg contnet is 12%. Use calcitic lime for the other 36 lbs/M for a total of 46 lbs.M of lime.
Last edited by Ridgerunner on Fri Feb 15, 2019 4:49 pm, edited 1 time in total.

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Re: Help Interpreting Soil Test

Post by LAlawnnut » Fri Feb 15, 2019 8:01 pm

Ridgerunner wrote:
Fri Feb 15, 2019 4:48 pm
Normally, I wouldn't suggested adjusting Mg levels. Seeing as you need lime, you might consider using some dolomitic lime to bring Mg up a touch. I'd suggest no more than 10 lbs of dolomitic per thousand square feet. That could raise Mg levels by 26 ppm if Mg contnet is 12%. Use calcitic lime for the other 36 lbs/M for a total of 46 lbs.M of lime.
How do I tell if it’s dolomitic?

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Re: Help Interpreting Soil Test

Post by LAlawnnut » Fri Feb 15, 2019 8:01 pm

g-man wrote:
Fri Feb 15, 2019 2:18 pm
It takes a long time. This is a marathon, not a 100 meter race. Apply the lime per the test recommendations and test next year around this timeframe.
I knew it took a while but I was wondering what a normal time frame is

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Re: Help Interpreting Soil Test

Post by Ridgerunner » Fri Feb 15, 2019 8:37 pm

LAlawnnut wrote:
Fri Feb 15, 2019 8:01 pm
Ridgerunner wrote:
Fri Feb 15, 2019 4:48 pm
Normally, I wouldn't suggested adjusting Mg levels. Seeing as you need lime, you might consider using some dolomitic lime to bring Mg up a touch. I'd suggest no more than 10 lbs of dolomitic per thousand square feet. That could raise Mg levels by 26 ppm if Mg contnet is 12%. Use calcitic lime for the other 36 lbs/M for a total of 46 lbs.M of lime.
How do I tell if it’s dolomitic?
The bag analysis label will say that it contains both calcium and magnesium. You want a lime that contains at least 10-12% Magnesium. The finer grind/mesh the better. Shop around and post what you find, if you like.
Here's an example https://www.lowes.com/pd/Sunniland-50-l ... 1000115093
Remember, only put down 10#/M of dolomite and the rest pure calcitic lime.

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Re: Help Interpreting Soil Test

Post by LAlawnnut » Fri Feb 15, 2019 8:51 pm

Ridgerunner wrote:
Fri Feb 15, 2019 8:37 pm
LAlawnnut wrote:
Fri Feb 15, 2019 8:01 pm
Ridgerunner wrote:
Fri Feb 15, 2019 4:48 pm
Normally, I wouldn't suggested adjusting Mg levels. Seeing as you need lime, you might consider using some dolomitic lime to bring Mg up a touch. I'd suggest no more than 10 lbs of dolomitic per thousand square feet. That could raise Mg levels by 26 ppm if Mg contnet is 12%. Use calcitic lime for the other 36 lbs/M for a total of 46 lbs.M of lime.
How do I tell if it’s dolomitic?
The bag analysis label will say that it contains both calcium and magnesium. You want a lime that contains at least 10-12% Magnesium. The finer grind/mesh the better. Shop around and post what you find, if you like.
Here's an example https://www.lowes.com/pd/Sunniland-50-l ... 1000115093
Remember, only put down 10#/M of dolomite and the rest pure calcitic lime.
Would I spread that by hand since it’s pulverized?

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