# Soil Test Results: give me the recs!



## OnTheLawn (Jul 23, 2020)

Alrighty folks, renovation last fall and spring is now here. Grass is starting to green up and so far I've only applied prodiamine and tenacity for some weed control. Here are the results for the soil test I just completed. Hit me with them recommendations!


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## ScottW (Sep 16, 2019)

You obviously told them this sample is for a lawn, so it's not that helpful IMO for them to tell you to apply 2 tons of lime per acre at "full rate" this spring. That's >90 lbs per 1000 sqft.
Recommendations from labs that know lawns will tell you to apply no more than 50 lbs lime per 1000 sqft in a single application. IMO you should do that app now. Try to get calcitic lime as opposed to dolomitic. Both your Ca and Mg levels are not very high. If you go dolomitic you'll risk overshooting with too much Mg relative to Ca, which can cause problems with soil compaction.
You could do a second app of lime at 40-50 lbs per 1000 later in the fall, then retest next spring and see where your pH is.

On the nutrients...
They are recommending 100 lb/A of N which is (100/43,560 sqft per acre=) 2.3 lbs N per 1000 sqft over the course of the year. That is not enough for TTTF that has been recently renovated. On an established lawn it would be sufficient if you were shooting for less work/mowing, but that is not your situation.
I would shoot for 3-4 lbs of N per 1000, with about 1/3 of that applied in the spring, and the remainder (most) going down in the fall. That recommendation for an equal share of N on July 15 is suspect. If you drop a big dose of N on TTTF in the middle of summer it will dramatically increase the risk of a fungus outbreak _especially_ on young TTTF. If the lawn actually looks hungry in summer (recognize that versus drought stress) you could use a low dose of organic fert, but that can be a game time decision.

Your ppm values and saturation % for potassium are pretty low. I'd shoot for 3-4 lbs per 1000, applied in 1 lb doses on 4-6 week intervals. The K can be applied through the summer without worry (unlike N). Try to use sulfate of potash (SOP) for your K source, as you could also use the small boost in sulfur.

TEC and OM are looking low. Is this sandy soil? If so, it will have difficulty retaining nutrients and in that case you might benefit from doing more frequent apps at lower amounts. For example instead of 1 lb every 4-6 weeks, you might apply 0.5 lbs every 2-3 weeks. Mulch your grass clippings, and your leaves in the fall, to try to keep more nutrients & OM in the soil.


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## OnTheLawn (Jul 23, 2020)

Thank you @ScottW ! Would you consider splitting the lime apps between dolimitic and calicitic? Do one now and the other in the fall? If so, which would you do first?

As for the nutrients, I was certainly not planning their recommended intervals haha. I'm going to up the N to 3-4 lbs like you said.

SOP is ordered and will be starting those apps next week.

Soil is sandy, yes. Was planning on doing more frequent feedings because of that, so glad to hear you recommend that as well.

Thank you much!


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## ScottW (Sep 16, 2019)

Your sandy soil is a bit outside my realm of experience. Mine is more of a clay loam. So you may care less about compaction issues from too much Mg (?). Maybe some other sandy soil folks will chime in.

The relative levels of the different cations affect their availability to the grass, and those relationships are more complex than my brain can hold without looking up charts and going down internet wormholes. The gist is that you don't want the balance to get so far out of whack that too much of one induces a deficiency in availability of another. Right now you're at a 4:1 Ca:Mg ratio (32% vs 8% saturation) which is fine. The overall levels seem low but that's probably a function of your soil type.

With sandy soil it might be fine to go with dolomitic lime, which is still calcium carbonate, just with a lot more magnesium carbonate. Or you could balance calcitic & dolomitic depending on what's available locally. I might do the calcitic first since your main concern is correcting the pH.
Here's one article on the topic.


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## Lawn Whisperer (Feb 15, 2021)

I ran across this article  that might help you decide between calcitic and dolomitic lime.

"In the heavy clay soil you need more calcium to help push apart the high clay component. Here, the ideal Ca:Mg ratio might be 7:1. Conversely, in the sandy soil you might need a Ca:Mg ratio of just 3:1, because you need more magnesium to help create structure in a soil where there is none."


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