Soil Test!

10 years ago

Hello all:

I am in my second year in the new digs. About 15K square foot yard in southeast PA (the very corner!) that hasn't been cared for around 10-15 years according to neighbors. It's a combination of tall fescue, barnyard grass, and weeds. I've attached the soil test I received while on vacation.

It's an improvement over last year.

The soil is heavily compacted clay. I'm looking to do a renovation, not a full redo. This year, I plan on putting down milorganite, dethatching, and aerating. In the fall, I want to work on the front yard and next fall is the back, depending on results.

Not looking to start an argument over their validity, but I choose to not put chemicals on my yard because I have small children.

I would be thrilled with any input or thoughts on how to proceed.

Thanks!

If anyone has additional questions, I'm happy to answer.

Featured Answer

User

10 years ago

Soy, Milo, and grains aren't going to fix some of this, but fortunately the required stuff isn't a problem. Where I thought you might have an issue (starter fertilizer), I gave you an alternative. It's much more expensive per thousand square feet, but...

CEC 9.6: For Delaware County, that's sand and silt with no equivocation. It's a nice CEC and holds enough resources that you don't have to constantly fiddle, but not so many that the soil is difficult to change.

pH 6.1: Just barely out of range of optimal...and probably not an accurate answer given your CEC and calcium amounts. Or, one reason I don't like Penn State tests. In reality, I'm thinking you're closer to 5.8. It doesn't matter much, I don't adjust the pH, I adjust the soil ions and the pH naturally follows along to settle where it should.

Organic Matter 4.5%: Firmly in the Good range. There's no reason to specifically raise this, although I always recommend mulch mowing and mowing all your fall leaves in. Combined with your CEC, your soil's in decent shape in terms of ability to bind resources.

Phosphorus 21: Just a little low (the chart makes it look like this is a desperate problem. It's not). I would like to kick this a bit, but only a bit. Normally, we'd use starter fertilizer (the cheapest, they're all the same) to fix this, but you can substitute triple superphosphate at 2.2 pounds per thousand square feet instead if you like and feed with soy, Milo, or grains. If they try to sell you soft rock phosphate as a "more organic" alternative, skip it. Sure, it's more organic, and I also hope you have 25 years to wait for the phosphorus to release. :-)

Calcium 41.6%: Or, why I think your pH is being read too high (probably getting the pH of the water used to test it). Optimal Ca saturation would be 60-70%, and for a CEC nearly perfectly in the middle, my target is 65%. That will generate a pH of around 6.5. We use calcitic lime to correct this because it's faster, doesn't add much in terms of elements I don't want to be adding, and it does tend to be cheaper per thousand square feet. I strongly recommend Encap, Mag-I-Cal, or Pennington Fast Lime. Recommendation below.

Magnesium 13.7%: Technically a touch high for your CEC (I'd target around 11-12%), the difference is so minor it's not worth discussing and certainly won't cause any issues at all. No magnesium required or desired.

Potassium 4.1%: This is a touch overinflated by your low calcium, but it's not as bad as the graph implies. For this year, let's ride it. No K required.

Minor elements: Not tested.

Recommendations:

July 15 (give or take): Apply 5 pounds of Encap, Mag-I-Cal, or Pennington Fast Lime per thousand square feet.

August 1: Feed with soy, Milorganite, or other grain to around 1 pound nitrogen per thousand square feet, give or take.

September 1: Apply starter fertilizer at the bag rate, OR apply TSP (Triple Superphosphate) at 2.2 pounds per thousand square feet (if using TSP, feed the lawn with soy, Milo, or grains).

October 1: Apply starter fertilizer at the bag rate, OR apply TSP (Triple Superphosphate) at 2.2 pounds per thousand square feet (optionally if using TSP, feed the lawn with soy, Milo, or grains).

October 15: Apply 8 pounds of Encap, Mag-I-Cal, or Pennington Fast Lime per thousand square feet.

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Comments (8)

User
10 years ago
You might be better off posting in the Organic Lawncare forum.

It's going to be very hard to make targeted adjustments without "chemicals".
hawksster .
10 years ago
Nah you can get help here with a fully organic program. Just to clarify, you don't want ANY chemical herbicides, roundup, fertilizers? Are you ok using bleach, baking soda, vinegar on your lawn? Do you have the time and ability to apply 300 lbs of of a dry grain product like cracked corn to your lawn?

I believe Morpheus lives up yonder near you. He's the guy who will give input on the lab results.
Trey thanked hawksster .
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User
10 years ago
Define "chemicals," because the ones I need to use here are calcium carbonate, and a salt of phosphoric acid (although I could theoretically do this on triple superphosphate or Milo...which, in Milo's case, is the same thing as a salt of phosphoric acid).

Both are either about as toxic as table salt...or less so.
Trey thanked User
Trey
Original Author
10 years ago
Thank you all for your input. Forgive the imprecise terminology, both hawksster and morpheus are correct. When I say no chemicals, I mean nothing synthetic or harsh. I do have both the time and ability to spread significant amounts of grain, soy, Milorganite, etc. No bleach. I'd have to look at whether baking soda or vinegar are problematic, but I wouldn't see why they are.

Thanks again.
Trey
Original Author
10 years ago
Wow, this is fantastic. Will be following very closely and will report back with results!

Thanks!
Trey
Original Author
10 years ago
One last question - if I follow this calendar, is there a particular timeframe on which to seed? I planned on almost scalping the ground and putting down a light layer of topsoil down as a bed for seed. Right now, the lawn is ~ 40-50% grass.

I had planned on seeding around September 5 as I will be out of town on Labor Day.

Thanks again!
User
10 years ago
I'd post a thread about that, because with a lawn that limited most people are going to recommend a full renovation. They're right on that point. But it's a bit difficult to do without glyphosate unless you have ample time to solarize.

However, the TSP or starter will actually help out the new lawn. While the October app of calcium on a new lawn with shallower root systems might make it go pale temporarily, it'll recover long before spring and won't be any further issue--nor will that paling out kill anything. Calcium is revoltingly harmless.