Lupton Soil Test - 2021

Learn how improving your soil can lead to a better looking lawn
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WIPool888
Posts: 22
Joined: August 24th, 2018, 4:52 pm
Location: Waunakee, WI (Madison)
Grass Type: Northern Mix
Lawn Size: 10000-20000
Level: Novice

Lupton Soil Test - 2021

Post by WIPool888 » April 22nd, 2021, 10:26 am

This is the third year soil test for this lawn. Lawn size is 15k sq. ft., and is from a new construction that was seeded in Spring of 2016. The grass is a northern mix blend. Mainly what the contractor laid down, but I've overseeded with Scotts twice. In general, it's come along very nicely. Still a couple weeds and seems to heat stress easily, but it looks just as good as the sod lawn next door.

Last year, the plan I followed was milorganite every 4 weeks, and 3 applications of fast acting gypsum (May-July-September). I was able to get down one application of boron as well. In the fall, I applied Urea twice. Once a couple weeks before the pause, then an application in November. The grass once again greened up very nicely this spring as a result, so thank you so much for the analysis/recommendations last year! The recommendations are working great! Did have quite a bit of vole damage this spring due to heavy snow in WI last winter. Link to last year's results/forum discussion is here:

2020: viewtopic.php?f=11&t=25796
2019: viewtopic.php?f=11&t=24893

In general, I'll still be shooting for the "Simple" approach since I work full time and have a 7 year old to keep up with, but I know I'll be putting in some work. If something is critical to make the lawn look better, I'll make time to get it done. I don't need the most perfect lawn in the world, but would like to have the best lawn on the block. I mow at least once a week, usually more often since it grows fast. Irrigation is as needed since I don't have in ground and it's not easy to water 15k sq. ft, but will certainly setup sprinklers before anything turns brown.

Please include a nitrogen component to my plan. Thanks!! Let me know if I missed any required information!

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MorpheusPA
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Location: Zone 6 (Eastern PA)
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Re: Lupton Soil Test - 2021

Post by MorpheusPA » April 22nd, 2021, 7:51 pm

I'd actually like both Andy and I to take a look at this. I'm going to do something a little....odd here. It's part of normal soil chemistry. It works. It's just that my amounts can use a second eyeball.

Your soil is a bit odd; it almost looks like somebody overlimed the soil with dolomitic limestone for a very long time, or you're simply in an area where dolomitic lime is natural to the soil. The magnesium levels are unbelievably high, and those alone are pushing the soil pH above neutral and into the alkaline range. Just adding calcium isn't going to help much with this.

Gypsum, however, will, by adding calcium that binds to the soil, and giving some of the magnesium a chance to rebind as magnesium sulfate (Epsom salt) that can wash out of the soil and head lower down, never to be seen again. You can order landscape gypsum at most garden stores or landscape places. Amounts here...20 pounds per thousand square feet or so.

Your lawn is large, so do what you can. If you can only manage 10, fine. If you can manage 30, great. Don't bother going above 30.

For feeding this year, find a good balanced fertilizer where all three numbers are the same. Your potassium levels are just a touch low, nothing to worry about really, but a little, and phosphorus could come up a little at that pH where I'd rather see 250-300. Balanced fertilizers can be 20-20-20 or 19-19-19 or 10-10-10 and it's fine. Apply at bag rate or, if there's no bag rate, ask. There's a simple equation we can run to tell you pounds per thousand square feet to drop.

Recommendations:

May-ish: Apply 10-30 pounds of gypsum per thousand square feet.

Memorial Day: Feed with balanced fertilizer at bag rate.

Labor Day: Feed with balanced fertilizer at bag rate.

October 1: Feed with any high-nitrogen fertilizer at bag rate (it's probably too late for the balanced there in WI).

If the grass is still green in November, feed one last time after your last mow with a high-nitrogen fertilizer at bag rate.

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MorpheusPA
Posts: 18129
Joined: March 5th, 2009, 7:32 pm
Location: Zone 6 (Eastern PA)
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Re: Lupton Soil Test - 2021

Post by MorpheusPA » April 22nd, 2021, 7:53 pm

(Yes, I saw copper and the manganese:iron ratio, but I'm ignoring those this year in favor of the elephant in the room).

WIPool888
Posts: 22
Joined: August 24th, 2018, 4:52 pm
Location: Waunakee, WI (Madison)
Grass Type: Northern Mix
Lawn Size: 10000-20000
Level: Novice

Re: Lupton Soil Test - 2021

Post by WIPool888 » April 27th, 2021, 3:53 pm

Thanks Morpheus! A few questions:

1. For the gypsum, I've been applying fast acting gypsum the last couple years. Should I stick with that or change it up to a heavier one time application of the regular garden gypsum? These are the readily available products near me:

https://www.menards.com/main/outdoors/g ... 499457.htm

https://www.fleetfarm.com/detail/encap- ... 0000345410

2. Last year Andy prescribed application of Boron if I can. Would you still recommend that based on this year's test?

3. For the balanced fertilizer, I should be applying 1 pound of nitrogen per 1k sq. ft., correct?

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MorpheusPA
Posts: 18129
Joined: March 5th, 2009, 7:32 pm
Location: Zone 6 (Eastern PA)
Grass Type: Elite KBG
Lawn Size: 10000-20000
Level: Advanced

Re: Lupton Soil Test - 2021

Post by MorpheusPA » April 28th, 2021, 5:55 pm

1. You can go with the garden gypsum; it'll be cheaper and we're going for mass here. Speed of reaction isn't a concern in this case and I'm content with a slow reaction over a period of months. With the garden gypsum, head closer to 30 pounds per thousand square feet if possible--I really do want mass, which is an advantage with the slow-reacting gypsum.

2. Boron is now approaching pretty good levels. A tad low for your pH, but high enough that it's not a problem for grasses (which are not boron-sensitive). You can let it ride this year.

3. Approximately, yes. The target should be in the 1 pound of N per thousand square foot range, which would also target 1 pound of P and K per thousand in this case.

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