# Spring vs Late Summer test lower SOP?



## 1028mountain (Oct 1, 2019)

I just got my soil test back from Waypoint and wondering why my potassium is lower now than it was in the spring after 2lbs/K of SOP from then until now? Also magnesium is lower too but I didn't do anything with that. Do I need to be applying more SOP then I have been as well as start adding magnesium?

Spring:









Late summer/early fall:


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## gpbrown60 (Apr 7, 2018)

No more magnesium or lime. More SOP would be fine. If you haven't applied your last fertilizer Carbon X 4-0-25 would be perfect for you. It has 25% Potassium and 10% Sulfur plus you get the carbon and chicken manure. The loss of potassium from spring to summer could be due to leaching out. The results from the added lime reduced your Organic Matter and CEC. Carbon would be beneficial to raise the Organic Matter and CEC. :thumbup:


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## 1028mountain (Oct 1, 2019)

@gpbrown60 super informative, thanks man! I did put down 2lb/k of SOP roughly 2 weeks ago. Should I still do the Carbon X 4-0-25? And if so can it go down during or right after an overseed?


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## g-man (Jun 15, 2017)

I think this is starting to micromanage your soil results.

First, there are always some sampling errors. Then there are testing variances.

Your soil is towards the low side of CEC, so it is not going to hold to nutrients too good. Phosphorus stays, but potassium and nitrogen leach into the subsoil. Adding OM should help you.

Then for every 1lb of N, the grass will use around 1/2lb if potassium. If you collect your clippings, you will be removing it from the soil.

Lastly, the threshold for potassium is 37ppm per MSLN. You are above 100ppm. Should you continue to add potassium? Yes to keep the levels, but it is not a big deal. Your grass will do fine and the extra potassium will not give you any extra performance.

Your magnesium is also fine (47ppm per MSLN). If you add more, you can make your soil harder.

Next time, do the full test to see your sulfur and iron levels.


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## gpbrown60 (Apr 7, 2018)

I think you will be fine to add more K but someone else can share their thoughts. Potassium is like radiator fluid for a car. It will prevent the lawn from stresses like extreme heat or cold. I have always heard the best time to apply is in the fall and it will not hurt your overseed during or right after.


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## 1028mountain (Oct 1, 2019)

What is OM? And @g-man you are saying to not to do anything differently then I have been?


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## KoopHawk (May 28, 2019)

OM = Organic Matter on your soil test

I agree with gman that this is micromanaging a bit. Generally if you take soil samples in the spring and make a fertilization plan for the season from the test, that should be sufficient until next spring's soil samples/test.


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## 1028mountain (Oct 1, 2019)

Ahh ok. So I'll just continue with SOP and take another test in the spring.


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## gpbrown60 (Apr 7, 2018)

Don't want to micromanage anyones soil results nor do I want to be admonished for giving advice. For edification you can use any product or products available to obtain the needed results.


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## 1028mountain (Oct 1, 2019)

@gpbrown60 i appreciate your help my man.


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## gpbrown60 (Apr 7, 2018)

1028mountain said:


> @gpbrown60 i appreciate your help my man.


Thanks, just trying to provide advice as no one had responded. I do it in good faith. If you noticed we said basically the same thing. It's all good!


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## g-man (Jun 15, 2017)

@gpbrown60 your advise is sound. He should continue to add more potassium and try to improve OM.

I think there are studies that Bermuda benefits from late potassium to reduce spring dead spots, but I'm not sure. I think the practice moved to the north, but I don't know of any studies/benefit. There is one study further north (wisconsin), that shows an increase of snow mold with late season potassium.


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## 1028mountain (Oct 1, 2019)

What the easiest way to improve OM? Carbon X STX?


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## gpbrown60 (Apr 7, 2018)

g-man said:


> @gpbrown60 your advise is sound. He should continue to add more potassium and try to improve OM.
> 
> I think there are studies that Bermuda benefits from late potassium to reduce spring dead spots, but I'm not sure. I think the practice moved to the north, but I don't know of any studies/benefit. There is one study further north (wisconsin), that shows an increase of snow mold with late season potassium.


We are good g-man. I will take the high road on this one. If I give bad advice let me know. Just trying to help members looking for answers. You and I both know there are many, many variables to consider. :thumbup:


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## Ridgerunner (May 16, 2017)

This:


> First, there are always some sampling errors. Then there are testing variances.
> 
> Your soil is towards the low side of CEC, so it is not going to hold to nutrients too good. Phosphorus stays, but potassium and nitrogen leach into the subsoil. Adding OM should help you.
> 
> Then for every 1lb of N, the grass will use around 1/2lb if potassium. If you collect your clippings, you will be removing it from the soil.


Plus, it can take 6-12 months for amendments to disperse and balance out. Also, if you disregarded g-man's advice and added lime, that scrambled everything. If you did follow his advice, then you have bigger issues as your pH somehow increased which is more than just a little unusual.


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## Ridgerunner (May 16, 2017)

@gpbrown60 
I think you might be overly sensitive in this instance. I didn't take g-man's comment about micromanaging as being directed to you at all but as a reference to OP's taking a second soil test so soon after the first test.


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## 1028mountain (Oct 1, 2019)

I added lime in the spring per the spring soil test results. The second test was from last week and no lime has been added since then.

What I want to know is how to increase organic matter? And what is soon? It's been 5 months since my first soil test. If anything I just wanted to know if what I've been doing has made any difference. Hell everyone on this site micromanages their yards.


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## Ridgerunner (May 16, 2017)

The problem here is that taking another soil test within 6 months (or even before a year is past) is going to give inaccurate results which are of no use, even if you want to micromanage.
The easiest source for OM is from root cycling, then from mulch mowing, next is mulching Fall leaves. Alternatively is topdressing with compost or peat moss, etc.


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## 1028mountain (Oct 1, 2019)

Thanks man. Will just continue with SOP and mulch what we I can.


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