All seeds grown in the high wind prairie, Midwest, in macro-climate zone 5(ish). Average dewpoint in summer is around 60. Soil is a loamy clay. Although my preference is organic, I have used commercial fertilizers from time to time. Growing Days approximately 135.
I’ve been meaning to do a soil test, the kind in which you send off the sample of your soil, for years. I have done the little vial do-it-yourself tests, finding them messy and confusing. Yes, I know my colors (I was successful in Kindergarten), but the results I got were the wrong color tone, making it hard to match and truly trust the results.
I first looked into sending a soil sample to our local extension. The extension locally doesn’t offer soil testing. I turned to searching online for a soil sample facility, looking at price, speed (as it was already March) and how comprehensive the results.
I chose Soil Savvy. They weren’t the most comprehensive, but they tested for what I needed.
Soil Savvy Tested For the Following:
N- Nitrogen Macronutrient
P- Phosphorus Macronutrient
K- Potassium/Potash Macronutrient
Ca-Calcium Micronutrient
Mg- Magnesium Micronutrient
S-Sulfur Micronutrient
Na-Sodium Micronutrient
Fe- Iron Micronutrient
Mn-Manganese Micronutrient
Zn- Zinc Micronutrient
Cu- Copper Micronutrient
B- Boron Micronutrient
pH- Acid or Base
Soil Savvy was fast, had a deal for 2 samples and tested for what I needed. Around $48 for both tests.
The Soil Test Process
Soil Savvy sent a small jar with a bar code label for each sample. A pre-paid and padded addressed envelope was provided for returning the samples via the regular US mail. The soil collection process was easy. Collect a small amount of soil with the included plastic scoop, put it in the jar, seal the jar, note the sample jar with a pen, note the barcode for yourself, then mail.
Soil Savvy advised to allow ten days for results after mailing back the soil sample in the pre-paid envelope. Even with the Covid Delay message listed on the website, I had my results within ten days. There is a section on the first page of the website “Get Your Report” that allows you to enter the needed info to see your results. Make sure you keep your barcodes, you’ll need them to access your report. I had an issue accessing my report; I reached out to customer service and they replied quickly. My only critique is that they ask for exact info when getting results. If you use multiple names, email addresses or any variable info, make sure you know which name, email, phone number and the bar codes before checking for results. Not sure why five fields are needed to get a soil sample report, but otherwise I was happy with Soil Savvy. Would buy again.
The Soil Test Results
My strategy with the soil testing was Before and After. Soil sample one was the Before, a section of the garden that is newly turned, only been in use and amended for one season.
The After sample two was from our oldest garden, the main garden, which is six years old. I wanted to see if the care I have taken to improve the soil actually made a difference. Were my amendments correct? If so, then I know what I need to make the Before soil as fruitful as the After soil.
Test Result One – BEFORE Garden
Test Result Two – AFTER Garden
What did my soil test results tell me?
Nitrogen – One of the primary building blocks for plants. Many people associate nitrogen primarily with leaf growth. Nitrogen is important for the roots, plant structure and growth. All tissues of the plant.
The Before garden has a bit more nitrogen than the After. Last season the soil of sample one grew peppers. The After garden grew tomatoes. Tomato plants are far larger, with more leaves and plant tissue, so I assume they simply use more nitrogen. I mulched both sections with grass clippings. The amendment differences between the two soil samples apparently aren’t impacting the nitrogen left in the soil five months after last harvest. Considering my mulching practices and the plants grown, I do not consider the difference between the two soil samples to be significant. I will focus on compost teas and grass clippings mulch, with an amendment of blood meal to all garden areas in late spring.
Phosphorus – Quite a difference between the Before and After soil samples. Phosphorus is critical to the ability of the root system to uptake and convert energy (sugars). As phosphate is returned to the soil, I assume that is why the Before soil sample has so much. I left many of the pepper plants to overwinter in the spot where I retrieved the sample. I pulled the plants located in the After section much earlier. I will research to see if that impacted the availability of phosphorus to the soil, as I am unsure the speed of breakdown of phosphorus back into the soil.
In any case, I will adjust any amendments to ensure they are low to no phosphorus, in particular the Before garden. It’s clearly not needed.
Potassium – Well, a clear difference here, and the clearest difference of what my amendments over time have done for my After main garden. My first at home dinky soil tests indicated I had no potassium in the soil, which I assumed was an error. I guess not. My native soil is genuinely very low in potassium. In fact, the plants in my main garden, the After garden, have always been a bit larger than plants elsewhere. Correlation is not causation, as soil is too complex to assign a problem to one factor with any certainty. Yet you bet your butt I’ve already purchased potassium to amend the garden beds this spring.
Calcium – no surprise I am off the charts in both gardens, I plant many plants with eggs or eggshells. Last season I also did a back-up application of powdered calcium. I do not have much blossom end rot in my fruits and veggies but when I do, it’s an uptake issue caused by temperature fluctuations (not lack of calcium) and only in varieties prone to BER. So I am not worried and won’t change what I have been doing.
Magnesium – is needed for plant metabolism, in particular processing chlorophyll. Magnesium is rarely deficient in clay soils. No surprises here.
Sodium – Sodium, like all the micronutrients, matters for plant metabolism. As you can see from the charts, there is a notable difference between Before and After gardens in their sodium concentration in the soil. We are currently in a drought, which can impact sodium levels in the soil. More water = less sodium. The After garden has better soil, perhaps it has the correct balance to retain moisture more than the Before gardens. Everything I have read seems to indicate it’s not a particular worry unless the sodium level is excessively high. Mine isn’t so I won’t be taking any action.
Iron – Iron, yet another micronutrient functioning as a metabolic assistant to plants. High calcium is often found in tandem with low iron. That might be a factor in my main garden. I am not too concerned about the iron levels in my gardens though.
Manganese – This micronutrient, beyond assisting plant function, is necessary for the uptake of nitrogen into plant tissue. I am manganese rich, so no action needed.
Zinc – VERY interesting. High phosphorus can result in lower zinc. Zinc seems quite critical to plant health and the ability to resist disease and plant tissue injury from the cold. Important here up north. I will be adding zinc to the soil when I amend the beds this spring. I have some Dr. Earth fertilizers including zinc, yet I am so deficient I will need to find a stand-alone amendment. Looking at the photographs of zinc deficient plants in past years confirms the suspected deficiency.
Copper – Another micronutrient needed for plant metabolism. A deficiency of copper is more common when the soil pH is 7 or above. Too much copper can be a problem, so beyond checking labels and not amending my soil with high copper amendments, not going to worry too much about copper.
Boron – A vital micronutrient needed for the physiology of the plant; the strength of the cell walls, structure and carbohydrate processing. I will be applying a Boron amendment with spring planting. Both gardens clearly need it. I wonder if my natural soil has more Boron, and my amendments have diluted the Boron available in the After garden.
pH – Exactly where I needed it to be for my primary vegetable gardens. Around 6.5. Slightly acidic.
Thoughts
I assumed my composting, burying kitchen scraps, mulching with leaves and grass clippings would supply me with all the macro and micronutrients my garden needed. I have tons of worms and the soil is very healthy and full of life. By visual inspection alone, it looks like my soil is in perfect, balanced health, as the life there thrives.
The lower Nitrogen was no surprise. I was, however, surprised by how much I actually have. I conduct high intensity gardening, which places a high burden on the nitrogen stores in the soil. I feel very good about the level of nitrogen in the soil after a very successful 2021 garden summer. I also rake dried leaves over the gardens for the winter, to encourage habitats for the smallest critters. Generally adding a heavy load of carbon (browns, dried plant matter) will further deplete nitrogen, as nitrogen is needed to break down carbon. I expected the Nitrogen to be at the Boron levels, almost completely gone. It wasn’t, I’m pretty happy.
The pH level was exactly where I wanted it to be. The Potassium level was a surprise, but my amendments have been a great benefit to my soil, as the amended garden is potassium perfection. I assumed, incorrectly, that my composting was enough. I was worried about the Iron as I have seem some leaf yellowing in the main canopy of some plants. These results lead me to think it’s the lack of Zinc that is causing that issue instead. Boron? I had no idea that was a need and wow am I glad I did the soil test. I never would have thought Boron was an issue otherwise. The Calcium and Sodium levels are where I expected.
Actions
I will be adding Potash (potassium) to the new gardens and Bloodmeal (nitrogen) to all gardens in late spring. I am purchasing a liquid micronutrient fertilizer to provide the needed Zinc and Boron.
I hope you found this helpful. Please see the sources below if you have further questions. I took a video of the process of collecting my soil samples, which I will add to this article and Youtube once edited.
SOURCES
About Nitrogen: https://extension.missouri.edu/publications/wq259
About Potassium: https://extension.umn.edu/phosphorus-and-potassium/potassium-crop-production
About Magnesium: https://extension.umn.edu/micro-and-secondary-macronutrients/magnesium-crop-production
About Sulfur: https://passel2.unl.edu/view/lesson/1daefadcf451/3
About Sodium: https://academic.oup.com/jxb/article/65/3/849/524705
About Iron: https://edis.ifas.ufl.edu/publication/SS555
About Manganese: http://nmsp.cals.cornell.edu/publications/factsheets/factsheet49.pdf
About Zinc: https://extension.umn.edu/micro-and-secondary-macronutrients/zinc-crop-production
About Copper: https://www.fdacs.gov/content/download/4675/file/Copper%20Deficiency%20of%20Plants.pdf
About Boron: https://ag.umass.edu/vegetable/fact-sheets/boron-deficiency
About pH: https://hortnews.extension.iastate.edu/2002/5-24-2002/soilph.html
Thanks for stopping by!
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