# Results are in - First Test



## JBC-1 (Apr 5, 2020)

Hi all,

First soil test results are in, and I'm having a hard time understanding what everything means here. Looking for a bit of guidance from the experts here. Thoughts?

There were 3 samples (Front, Back, Side Yards)


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## Ridgerunner (May 16, 2017)

You can find the sufficiency level ranges and short explanations of the different tests in my thread:https://thelawnforum.com/viewtopic.php?f=24&t=1088
Scroll down and look for topic headings entitled Phosphorous, Bray, Olsen and Ammonium Acetate.
There are also sections explaining how to calculated the addition of the different nutrients (phosphphorous, Potassium, Magnesium, etc.) based on the results of a soil test.
After taking a look at that, if any questions, feel free to ask.


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## JBC-1 (Apr 5, 2020)

Wow. That's a very detailed thread. It took me some time, but here is what I have captured through my readings.

I need to apply the following per 1000 sq. ft;

Front Yard
N - ?
P - 1.6lbs
K - (-9.65)

Back Yard
N - ?
P - 9lbs
K - 1.4lbs

Side Yard
N - ?
P - 13.25lbs
K - 2.2lbs

I don't know what amount of N I should be applying, as there are no results on my test. Now with using the above, if I choose a starter fertilizer of 5-20-20, will that work? If so, how do I now determine how much to apply?


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## g-man (Jun 15, 2017)

Nitrogen is not normally measured. You need to apply nitrogen to get grass to grow when it visually needs it.

For P and K, check the soil remediation guide in my signature for products, rates. There is a big difference between your soils, do you know why?


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## JBC-1 (Apr 5, 2020)

I am not 100% sure why there is a big difference. The only thing I can really think of, is throughout the years, I would top dress and overseed in certain areas. My front would normally get the most attention, while the back and side not as much. So maybe there is less organic material applied throughout the years?

Also, the side yard had a large grub problem two years back, and now I am finding I have grubs in my front, and back yards, but did not see any in the side.

In regards to how much to apply, I know there are many options, but some are limited to what I can get here in Canada (at least I think).

I can get a Scott's starter fertilizer (24-25-4), or I can get a (5-20-20) directly from a sod farm. I think I get how much is needed to bring my numbers up, but if I use the 5-20-20 then how much should I be applying per application, and how often? The recommended rate (per the bag) is 5lbs per 1000 sq. ft.

Sorry for all the questions, I am still learning. I appreciate the advice given so far!


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## Ridgerunner (May 16, 2017)

My quick calculations don't comport with yours. We have our wires crossed somewhere. I think I may have referred you to the section of my thread that gets into pretty convoluted calculations. Let's stick with the first section "the Simple Method."
Phosphorous; A&L used the Olsen method for testing your P levels. The sufficiency range for P Olsen results is 12 - 28 ppm (we'll avoid a discussion of all of the parameters and qualifiers). That means if your soil's P levels fall between 12 and 28 ppm, your soil should be able to supply the turf with all the P it needs for the current growing season.
P in any fertilizer bag is measure as P2O5. Hence, that bag of 5-20-20 contains 20% P2O5. If you apply 5lbs of that product over 1000sq ft. You will have applied one pound of P2O5. One pound of P2O5 over 1000 sq ft will add 9 ppm (actually, it's closer to 9.5, but we're keeping it simple) to soil P levels.
Your sample 61 levels are 27 ppm. Within Range (12_28) No need to add more P to this buffer/reserve amount. Your sample 62 level is 13 ppm. Within range (12-28) but doesn't provide much of a reserve buffer. To provide some insurance of availability, it is suggested that this be raised to 20 or slightly more. Adding one pound of P2O5 can add 9 ppm making your soil level 22. ppm. That should make for a good buffer/reserve level. Your sample 63 is 5 ppm., well below the 12-28 range. Adding 2 lbs/thousand of P2O5 can add 18 ppm of P to your soil for a total level of 23 ppm. A good buffer/reserve level.
Potassium
A&L used ammonium acetate to measure potassium levels. The ammonium acetate sufficiency range for your soil CEC is 100 - 235 ppm.
The Potassium in any bag of fertilizer is measured as K2O. Hence, that bag of 5-20-20 contains 20% K2O. If you apply 5lbs of that product over 1000sq ft. You will have applied one pound of K2O. One pound of K2O over 1000 sq ft will add 18 ppm (actually, it's 18.125, but, again, we're keeping it simple) to soil K levels.
Your sample 61 levels are 165 ppm. Within Range (100-235) No need to add more K to this buffer/reserve amount. Your sample 62 level is 125 ppm. Within range (100-235) but doesn't provide much of a reserve buffer. To provide some insurance of availability and consistency with sample 61, it is suggested that this be raised to 160ish or slightly more. Adding 2 pounds of K2O can add 36 ppm making your soil level 161 ppm. That should make for a good buffer/reserve level. Your sample 63 is 122 ppm. Adding 2 lbs/thousand of K2O can add 36 ppm of K to your soil for a total level of 158 ppm. A good enough buffer/reserve level without splitting hairs.
I've called the above levels "buffer/reserve" levels for a reason. I intend them to be kept in the soil's pantry should the turf need to make an unanticipated withdrawal greater than the regular allowance it will be given bellow.
The Regular Allowance
You have cool season turf. For every 1 lb /thousand of N applied, cool season turf will use 0.3 lbs of P2O5 and between 0.6 and 0.9 lbs of K2O.
If you plan to make four applications of N this year for a total of 4lbs/thousand of N, you will also want to apply 1.2 lbs/thousand of P2O5 and 3.6 lbs/thousand (starting at the high end of the .6-.9 range) of K2O.
Using Sample 63 as an example:
Total N for the year: 4 lbs
Total P: 2lbs/thousand for the reserve and 1.2 lbs/thousand for the regular allowance = 3.2 lbs total of P2O5
Total K: 2lbs/thousand for the reserve and 3.6 lbs/thousand for the regular allowance = 5.6 lbs/thousand total of K2O.

Distribute the total amount of P2O5 (3.2 lbs) and the K2O (5.6 lbs) evenly over the season. 
Do not apply more than 1 lb of any nutrient at a time and do not apply more than 1 lb/thousand of any nutrient with a 30 day period.
Questions?


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## JBC-1 (Apr 5, 2020)

@Ridgerunner thank you for the detailed reply, and breaking everything down for me.

Sorry for the late reply here. Got a bit tied up with work.

So I get everything that you mentioned, however am still confused on the math.

Using the 5-20-20 and applying 5lbs per application. According to my calculations, I am only actually applying 0.22lbs of N, 0.88lbs of P and 0.88lbs of K.

So if I am to apply 1lb of N per application, does that mean I need to apply 20lbs per application now? (1lb of N / 0.05 = 20)?If that is true, then am I not applying 4lbs of P and K during one application which is too much?

Your post mentioned that if I apply 5lbs over 1000sq ft. I would have applied 1lb of P and K. How did you determine that number?

This is where I am getting confused the most.


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## Ridgerunner (May 16, 2017)

Let's do this one issue at a time.


> Using the 5-20-20 and applying 5lbs per application. According to my calculations, I am only actually applying 0.22lbs of N, 0.88lbs of P and 0.88lbs of K.


A bag of 5-20-20 fertilizer means that 5% of the bag is N, 20% is (reported as) P2O5, and 20% is (reported as) K2O. (more on P2O5 and K2O later).
That also means every pound of 5-20-20 product contains 5% N, 20% P2O5 and 20% K2O.
Therefore: 
5 lbs of 5-20-20 is .25 lbs of N (5 X .05 = .25), 1 lb of P2O5 (5 X .20 = 1) and 1 lb of K2O (5 X .20 = 1).
How did you calculate 0.22lbs of N, 0.88lbs of P and 0.88lbs of K?


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## JBC-1 (Apr 5, 2020)

Okay that is easier. What I was doing was calculating how much lbs of each were in a total bag. Then from there taking the 5lbs being applied and thus ended up with 0.22, 0.88 and 0.88.


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## Ridgerunner (May 16, 2017)

On to part 2 if you're still interested.


> So if I am to apply 1lb of N per application, does that mean I need to apply 20lbs per application now? (1lb of N / 0.05 = 20)?If that is true, then am I not applying 4lbs of P and K during one application which is too much?


The rule of thumb (it's an arbitrary rule) is that you should not apply more than 1#/M of elemental N,P or K within a 30 day period/month. MY RULE is that you should not apply more than 1#/M of N or P2O5 or K2O within a 30 day period/month. 
Consquently, when determining the maximum ammount of any fertilizer to be applied in a month's period, you calculate using the largest number on the bag. The largest number on the bag of 5-20-20 is "20". To calculate the maximum amount of 5-20-20 that we can apply without breakin the 1#M rule, divide 1 by .20. 1 / .20 = 5 lbs of the 5-20-20 product. To determine how much of any other nutrient we will be applying at that 5#/M rate we multiply each Nutrient by it's corresponding percentage value. e.g. 5 lbs of product X .05 (5%) = .25 lbs on N and 5 lbs of product X .20 (20%) = 1 lb of P2O5.

( *TMI, READ AT YOUR OWN RISK:* P2O5 and K2O are just arcane units of measurement derived from the methods used in chemical formulas from the early days of chemistry hundreds of years ago. A fertilizer bag does NOT contain either K2O or P2O5. A number of different chemicals are used to supply the K and P in a bag of fertilizer (SOP, MAP, TSP, DAP, MOP etc.) but the fertilizer companies convert the actual bag amount of elemental P into units of P2O5 and elemental K into K2O and report that as % of P2O5 and K2O on the bag label. (fortunately, they report N as elemental N, so no confusion needed)P2O5 is 43% elemental P and K2O is 83% elemental K. So that 50# bag of 5-20-20 contains 20% of P2O5 units of P (read as: 10 lbs of P2O5) which is actually only 4.3 lbs of elemental P. That 50# bag of 5-20-20 also contains 20% of K2O units of K (read as:10 lbs of K2O) which is actually only 8.3 lbs of elemental K. I think it's just easier to use the Simplified Method than to attempt to wade though and calculate all that.)


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## JBC-1 (Apr 5, 2020)

Yes still interested. I like the way you are breaking this down for me, and I agree, it's easier to use the simplified method.

Okay, so I think I understand this now. With that said, it leads me to the next part.

After speaking with a rep from a commercial supplier they agreed to supply me with their product. I will be using 5-26-25 for spring, and fall applications, then using 21-0-0 for the summer app's as needed.

Now the rep recommended to apply 20lbs per application of the 5-26-25, but using your calculations I would be applying way more than 1lb of the P and K (5.2lbs and 5lbs). So how do I dinnertime how much lbs I should be applying. Or do I just determine that as per my results I should apply at least 1lbs of P (lowest number), then calculate based on that, which would come out to be 3.84lbs/1000?


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## Ridgerunner (May 16, 2017)

The rep recommends a Spring and A Fall application for a total of 10.4 lbs/M of P2O5 and 10lbs?m of K2O?
Please re-read my second post of April 11 and do the calculations and compare my recs to his. Calculated how many ppm of P and K that will add. I can't say that the reps quantities will hurt the turf, probably not, but it is well above the amounts necessary, is wasteful and there is a chance it could be detrimental. Why are you wanting to go with a low N, high P and K fertilizer? Have you looked for 21-0-0 or 46-0-0 and 0-45-0 and 0-0-50 or similar? or a 20-10-20 or similar and a 15-0-15? It's not ideal, but the simplest, easiest would be to find 10-10-10 and use that. The choice is yours,. Good luck.


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## JBC-1 (Apr 5, 2020)

Okay, I am back for part three now...LOL

Here is where I stand. (Thank you for all the advice so far).

I have three options of fertilizer to choose from for spring/fall applications, but do not know which one to choose. I do know no matter which one I choose I will not be applying more than 1lb of N/M. Thoughts on which one you would choose?
5-26-25 - recommended by rep I am working with
16-32-6
18-24-12

For all other applications I will be using 21-0-0, so I am set with that.

Now comes the next part. My grass is looking pretty bad in certain spots (grubs), and very thin in others. The question here is, should I do the following;

Opt1 - Aerate, top dress, overseed and fertilize
Opt2 - Aerate, overseed, top with peat then fertilize
Opt3 - None of the above, except fertilize - wait until fall to repair

Front Yard showing grub damage


Side Yard showing very thin lawn


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## Ridgerunner (May 16, 2017)

On plots 29 and 30, you can use the 18-24-12 for 2-3 fert applications (you could consider using it for 3-4 applications on plot 30). Use the 21-0-0 for plot 28 and for any additional ferts for plots 29 and 30. Retest next year and see where you are. I think it would be much more effective to find 0-0-46 or MAP for phosphorous and SOP for K or just use a Triple NPK (10-10-10, 13-13-13, 20-20-20 etc)


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## Ridgerunner (May 16, 2017)

> no matter which one I choose I will not be applying more than 1lb of N/M.


The rule of thumb is that you should not apply more than 1 pound of any nutrient in a month period, not just N.
Using the largest number in the analysis:
18-24-12
100 / 24 = 4.16 lbs, so apply no more than 4.16 pounds of product per thousand even though that will only result in applying 0.75 lbs of N/ thousand (4.16 X .18 i.e. 18% = 0.749 lbs) and 0.5 lbs of K/M (4.16 X.12 i.e. 12% = 0.499 lbs).


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## JBC-1 (Apr 5, 2020)

@Ridgerunner thank you for all of the feedback. It is greatly appreciated. I will go with the options you mentioned.

Now, any opinions on what I should do to try and fix my lawn as per the above pictures and options?


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## JBC-1 (Apr 5, 2020)

Back this morning to get a bit more knowledge. @Ridgerunner you have been super helpful. I just re-read your posts from above but have a question or two for you if you don't mind. Sorry for all the questions in advanced.

On May 16th I applied 5-20-20, topdressed, over seeded and applied peat moss. I applied at a rate of 5 lbs / M

Using your calculations above and my test results, I've determined how much P and K I need to apply for the season. 
From what I have already applied above, the question is when do I apply more, and how do I incorporate more N, since it has barley gotten any for the season?

I am getting 21-0-0 on Monday, and wanted to apply that, as there are some brown thinning spots that I "think" is lacking N, and the lawn is turning a light green vs. my neighbors who's are a dark deep green. Should I just apply 21-0-0 to fulfill my N needs, but then still be lacking in the P and K areas? And how soon is too soon to apply fertilizer again, since I applied only two weeks ago?

Plan is to cut today, then apply Killex (as I just got my shipment in a few days ago).

Image to show browning thin areas.


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## Ridgerunner (May 16, 2017)

Yes. just use the 21-0-0 to add the amount of N you want monthly above what you get from the 5-20-20. The rule is no more than 1lb/M of N or P or K within 30 days, but this week you could put down 3lbs/M of the 5-20-20 product again and another 3-4lbs/M of the 21-0-0 product. Then wait until the end of August to restart the regiment: 5lbs of of the 5-20-20 product and 3-4 lbs of the 21-0-0 product every month until the end of November.


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## JBC-1 (Apr 5, 2020)

Wow, that's awesome news. I didn't know I could apply both types of fertilizer at the same time.

One more quick question...considering these are both fast release fertilizers, if I apply in the next week, then not apply anything more until the end of August, would my lawn not be deprived of nutrients throughout the summer months?

Also, since I have never applied Killex before, any tips? I have the concentrate version, which I will mix in a sprayer. I have a lot of weeds all around. See below.


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## Ridgerunner (May 16, 2017)

Cool season Turf plant growth slows during the heat of summer, so the plant doesn't use much in the way of nutrients. Attempting to push growth with N applications can stress the turf making it more susceptible to heat stress and disease. If you have irrigation and monitor your lawn closely, it's up to you if you want to try metering N application during summer. P and K (lower amts for MOP) apps can be continued during summer, but even in deficient soils, it's not necessary. I can't answer your weed killer questions.


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