Quick Questions Prior to Pulling Soil Samples

[R2k]

Andy/Morph -

Will I get accurate soil test results if I pull soil samples today given the inputs I've already put down for the year or should I wait?

I'm also considering getting the saturated paste test in addition to the standard soil test. Will you folks be able to interpret this data and do you agree it's of value? Logan labs of course.

Goals: To continue managing and perfecting my high-performance lawn with the darkest green color possible and thickness while being able to handle the summer stress with the least die-out possible. I want to achieve these things through soil nutrient balance and by improving my soil structure.

7k sqft total lawn space on 90% silt/ 10% sand soil (13 years since I've done this test...). I've bolded some of the heavy apps I wanted to call out. These are the inputs in the last 6 months (I'm omitting N and tiny apps of P & K for simplicity):

*Note: the lbs per K is the actual product from the bag.
9/19/22 - 2 lbs per K Potassium Sulfate(SOP) (0-0-48)
9/20/22 - 3.57 lbs per K Elemental Sulfur
9/21/22 - 2 lbs per K Ironite
10/1/22 - 2 lbs per K Fast Acting Gypsum (Earth Science brand)
10/6/22 - 2 lbs per K Ironite
10/9/22 - Fast Acting Gypsum (Earth Science brand) 2 lbs per K
10/21/22 - 2 lbs per K Ironite
11/7/22 - 2 lbs per K Ironite
12/5/22 - 2 lbs per K Ironite
2/15/23 - 5.7 lbs per K Super Iron Plus (16.5% iron humate, 1% Manganese of which 0.4% is soluble, 2% total & soluble Magnesium)
3/23/23 - 51.43 lbs per K of traditional gypsum
3/24/23 - 5.7 lbs per K Super Iron Plus
3/24/23 - 17 lbs per K of Ammonium Sulfate (20.5-0-0 24% Sulfur)
4/5/23 - 17 lbs per K of Ammonium Sulfate
4/5/23 - 2 lbs per K Potassium Sulfate(SOP)
4/21/23 - 1 lbs per K Andersens Humic DG
4/21/23 - 1 lbs per K of Iron Sulfate (30% iron)
4/21/23 - 0.93 lbs per K of Ammonium Sulfate
4/21/23 - 0.5 lbs per K of SOP


Super Iron Plus Label, if needed:


Gypsum label from my 3/23/23 application:


My backyard soil test from Nov 2022 for some context:





Sorry for the big list. I went out on a limb with the gypsum treatments to raise calcium and lower the magnesium in the base saturations...feel like I'm going to get a talkin' to on that. I welcome any critical feedback and corrections of any misunderstandings I have. Also, I am not using Ironite or Super Iron Plus anymore (SIP was a limited experiment, I don't want any more Mag obviously).

Thanks and have a great day!

[andy10917]

I recommend waiting 4 weeks before testing after nutrients are applied.

I don't recommend paste tests any more. I haven't seen one in a long while that told me anything I didn't already know.

[R2k]

Sounds good.

Thank you, Andy!

[MorpheusPA]

Agreed, and that makes the first test date window for 5/21/23. I'd be inclined to wait a bit longer. Fifty pounds of gypsum isn't going to go down easily.

[R2k]

Preferably, I would like to keep my options open for additional (but limited) nitrogen/SOP/iron sulfate in May & June.

What date would you consider ideal given my gypsum situation? I can work my fertilizer apps around your ideal date.

Thanks, guys!

[MorpheusPA]

I'm not terribly worked up by nitrogen applications, so you can go ahead with May nitrogen apps if you like. Just don't drop iron sulfate until after your soil tests are taken. Say, end of May, beginning of June.

While I was momentarily tempted to...no. Just take the samples normally.

[R2k]

Thank you, Morph.

Because I don't know what I don't know, I'm going to get specific for a moment just so the tests are accurate.

For N, I like ammonium sulfate and Milo. Does it matter which one I use during the May lockout period? Should I consider something else for N?

We're clear not to use iron sulfate. How about potassium sulfate (SOP 0-0-48)? I assume the answer is to not use it, but want to confirm.

Thanks again!

[MorpheusPA]

I'm not worried at all about the nitrogen source. Ammonium sulfate, urea, organic, whatever you like.

Skip iron sulfate and potassium sulfate until we get the test back and read it.

[R2k]

Awesome, thank you for clarifying!