# How long to wait after fertilizing to do a soil test



## DT1986 (May 3, 2018)

Hi, I fertilized my lawn with milo blended in with some quick release kind (Connor style) 7 days ago. How long do i now have to wait before I can send in a soil sample without skewing the results?


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## kur1j (Jul 2, 2017)

I honestly don't feel it will matter. N is short lived and isn't very meaningful on the test. If you only applied N then that won't really affect what you would need to do. The milo (i've never dealt with it) is broken down by microbial activity. I wouldn't think 7 days you would have enough activity to scew the P and K results. On top of that P from my understanding takes a long time (months?) to move down into the soil anyways.

But that's my take on it. I would just do it and then you could state what you did before the test result.

If I'm completely wrong someone feel free to correct me.

Edit: Yup think I'm wrong. Apparently my assumptions and what I read in other sources weren't so great.


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## social port (Jun 19, 2017)

I'm not sure that there is a bulletproof answer here-and different labs may advise for different timeframes.

I would wait a full month, if not a week or two longer.


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## Ridgerunner (May 16, 2017)

As the labs only test a couple of grams or cubic centimeters of soil taken out of that cup or two of sample we send, it's important that we avoid including a prill, or a prill fragment of fertilizer that would skew the results. It takes some time for a prill of fertilizer or any amendment to dissolve and disperse. Personally, I like to take my soil samples in the Spring before I apply anything to my lawn. Anything that was applied the prior year will have had time to work "cook" itself into the soil. In this case, I'd suggest that you just avoid the top half inch of the soil sample and not include it in the sample. Carfully avoid any of that cop half inch from inclusion so that no remaining fertilizer prill of fragment gets into the sample. For instance don't remove the top half inch of the core while holding it over the collection bucket, use common sense. Your lab results won't include recent fertilizer applications, but you can account for that somewhat, but the results will still be useful whereas if they are tainted and skewed, they will be meaningless. For the most accurate results, remember to take 8 samples per each 3-3500 square foot of lawn. Keep the depth consistent. include the whole depth of the core (except that top 1/2"). Mix all the cores together well.


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## DT1986 (May 3, 2018)

Thank you all. I think I will play it safe and wait till next spring for a soil test.


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