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Logan Labs Soil Test Results advice - high phos., low nutrients

8 years ago
last modified: 8 years ago

Hi all, I'm looking for some collective wisdom regarding the results of my soil test. I've been reading the various soil test threads and want to be sure I'm on the right path.

A little background: I'm new to this property. It's a small, shady backyard in a semi-urban area (houses fairly close together, concrete driveway and paths, a parking lot behind the fence in the back). Last fall I put in some grass after clearing out the weeds & overgrowth. I tilled in some compost prior to seeding and followed a basic fertilization schedule: starter fert. and rapid-lime (calcitic) at seeding (I used a Rapitest litmus test to guesstimate pH), half-rate of starter fert about a month later, then a final high-nitro winterizing fertilizer before the winter. I haven't added anything to the Lawn since then. I have kelp/humic sprays, compost tea, and SBM on deck but I was waiting to see the results of the tests first.

The Test Results

I also sent three other samples to Logan for the plant beds that surround the Lawn. The Lawn test results are highlighted in yellow:

If this is hard to read (houzz seems to shrink all images), you can see a full-size version here

My Interpretation

1. pH - I knew the soil was acidic (judging by the Rapitest) but was surprised to see it this low in the lawn area, especially as I had limed it last fall though at less than bag-rate (I wasn't sure how much or how fast it would impact pH). The azaleas & rhododendron will be happy.

2. EC & OM - These seem to be some of the few positives. The ECs echo my soil jar tests - silt loam to loamy sand, but mostly sandy loam.

2. P - The high phosphorus was alarming but from what I've been reading in other threads there isn't much to be done other than to avoid more phosphorus.

3. Low nutrients (Cal, Mag, K) - Not really surprised with this as I'm not sure how much maintenance the previous owner was doing (other than dumping high-P fert. on his flower beds) and the nature of the surrounding area.

4. High heavy metals (esp. Cu, Zn, Al) - A bit disconcerting but also not surprising (parking lot runoff? water supply? NJ acid rain?). From what I've read in other threads, the high Aluminum seems to be common in the Northeast. There doesn't seem to be much that can be done here either other than to avoid adding more of these elements. The iron level appears to be fine, though I presumably shouldn't be adding more. Boron & manganese deficiencies will need to be addressed.

What To Do/My Conclusions/Questions

Not the most favorable test results, but I'm hoping the issues can be remedied without too much pain.

From what I've gathered from other soil test threads, the options include:

- Do regular applications (2-3x per year) of dolomitic lime at max bag-rate to bring up the pH and increase Cal & Mag levels (using something like Mag Turf Pro), and potassium sulfate to boost K levels.

- Alternatively, what about using calcitic lime along with Sul-Po-Mag (or K & Mag sulfate separately)? Wouldn't these be faster-acting? Or am I better off with the first option? Do I want to be avoiding any additional sulfur?

- Address the B & Mn deficiencies with appropriate compounds (Borax, Mn-sulfate). How often and at what rate considering my EC? Do these need to be addressed right now, or will they improve over time as the other nutrients balance out and the OM hopefully gets broken down? Is there an amendment that would help with both? I was looking at various rock dusts, but they all seem to have higher levels of Al, Cu or Zn, which I don't need.

- What about the surrounding plant beds? I don't want to raise pH too much there as most of the plants are the acid-loving kind. I'm assuming using gypsum and K/Mag sulfate would be better options, along with any organic supplements (eggshells, worm castings).

This sounds like a lot of sulfates. How much will these repeated applications spike sulfur content?

Anything else that I'm missing?

Any help/comments appreciated!

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