Soil Test of the Vegetable Gardens

Posted July 25, 2023

Summary of Amounts of Available Nutrients to Add per 100 sq ft:

Available Phosphorus (P) Via Rock Phosphate: Approximately 18.57 lbs per 100 sq ft
Available Sulfur (S) Via Gypsum: Approximately 2.35 lbs per 100 sq ft
Available Magnesium (Mg) Via Dolomite: Approximately 0.5 lbs per 100 sq ft
Available Nitrogen (N) Via Organic Blend: Approximately 11.67 lbs per 100 sq ft
Available Potassium (K) Via Organic Blend: Approximately 10 lbs per 100 sq ft
Available Boron (B) Via Borax: Approximately 2tbspn in 10 gallons of water per 100 sq ft
Lime: Approximately 28 lbs per 100 sq ft.

Note: Apply lime each year until a subsequent soil test indicates otherwise.

Distribute the amendments evenly across the area to ensure proper nutrient distribution and improve soil fertility for healthier plant growth.

As always, follow the soil test recommendations and consider the specific needs of your crops and soil conditions for optimal results. Regular soil testing and expert advice will help you fine-tune the application rates and maintain a balanced and healthy growing environment.

Summary of Available Nutrients to Add Per 100 sq ft (in Cups):

Available Phosphorus (P) Via Rock Phosphate: Approximately 21 cups
Available Sulfur (S) Via Gypsum: Approximately 2 cups
Available Magnesium (Mg) Via Dolomite: Approximately 1 cup
Available Nitrogen (N) Via Organic Blend: Approximately 35 cups
Available Potassium (K) Via Organic Blend: Approximately 30 cups
Available Boron (B) Via Borax: Approximately 2 tablespoons per 10 gallons (Boron recommendation, not included in the previous summary).
Lime: Approximately 16 cups.

Regular soil testing and expert advice will help you fine-tune the application rates and maintain a balanced and healthy growing environment.

Set Baseline Targets for Soil Fertility

Steve Solomon’s recommended PPM (parts per million) targets and base saturation targets for soil fertility in his book “The Intelligent Gardener” are as follows:

PPM Targets:

Calcium (Ca): Around 600-2,000 ppm
Magnesium (Mg): Around 100-300 ppm
Potassium (K): Around 300-600 ppm
Phosphorus (P): Around 20-100 ppm
Sulfur (S): Around 100-200 ppm
Zinc (Zn): Around 2-5 ppm
Copper (Cu): Around 1-2 ppm
Boron (B): Around 0.5-2 ppm
Iron (Fe): Around 20-100 ppm
Manganese (Mn): Around 10-50 ppm

Base Saturation Targets:

Calcium (Ca): Around 65-75%
Magnesium (Mg): Around 12-20%
Potassium (K): Around 2-5%
Sodium (Na): Around 0.5-3%
Hydrogen (H): Around 5-10%
Other cations (such as ammonium, aluminum, etc.): Should be very low or negligible in well-balanced soils.

It’s important to note that these targets are not rigid rules but general guidelines for maintaining healthy and fertile soil. Soil composition can vary based on the specific needs of the plants you are growing and your local climate conditions. Conducting a soil test is the best way to determine the nutrient levels and pH of your soil, which will help you make more precise adjustments to meet your garden’s requirements.

Set Targets at higher range for maximum nutrient density

let’s set the targets at the higher range for this conversation. Here are the higher range PPM targets and base saturation targets based on Steve Solomon’s recommendations from “The Intelligent Gardener”:

PPM Targets (higher range):
- Calcium (Ca): Around 2,000 ppm
- Magnesium (Mg): Around 300 ppm
- Potassium (K): Around 600 ppm
- Phosphorus (P): Around 100 ppm
- Sulfur (S): Around 200 ppm
- Zinc (Zn): Around 5 ppm
- Copper (Cu): Around 2 ppm
- Boron (B): Around 2 ppm
- Iron (Fe): Around 100 ppm
- Manganese (Mn): Around 50 ppm
Base Saturation Targets (higher range):
- Calcium (Ca): Around 75%
- Magnesium (Mg): Around 20%
- Potassium (K): Around 5%
- Sodium (Na): Around 3%
- Hydrogen (H): Around 10%

Compare with your Soil Test Numbers

Soil Test Data:

Phosphorus (P): 22 ppm (Target Higher Range: 100 ppm)
Potassium (K): 120 ppm (Target Higher Range: 600 ppm)
Magnesium (Mg): 263 ppm (Target Higher Range: 300 ppm)
Calcium (Ca): 1180 ppm (Target Higher Range: 2000 ppm)
Sulfur (S): 11 ppm (Target Higher Range: 200 ppm)
Zinc (Zn): 6.3 ppm (Target Higher Range: 5 ppm)
Manganese (Mn): 31 ppm (Target Higher Range: 50 ppm)
Iron (Fe): 90 ppm (Target Higher Range: 100 ppm)
Copper (Cu): 1.2 ppm (Target Higher Range: 2 ppm)
Boron (B): 0.2 ppm (Target Higher Range: 2 ppm)

Base Saturation Percentage from Soil Test Data:

% Phosphorus (P): 3% (Target Higher Range: Not provided in the initial targets)
% Potassium (K): 1.5% (Target Higher Range: 5%)
% Magnesium (Mg): 10.7% (Target Higher Range: 20%)
% Calcium (Ca): 28.8% (Target Higher Range: 75%)
% Hydrogen (H): 58.3% (Less than : 10%)
% Sodium (Na): 0.7% (Less than: 3%)

Comparison Analysis:

Phosphorus (P) is significantly below the target higher range and should be increased.
Potassium (K) is below the target higher range and should be increased.
Magnesium (Mg) is below the target higher range and should be increased.
Calcium (Ca) is within the target higher range.
Sulfur (S) is significantly below the target higher range and should be increased.
Zinc (Zn) is within the target higher range.
Manganese (Mn) is below the target higher range and should be increased.
Iron (Fe) is within the target higher range.
Copper (Cu) is below the target higher range and should be increased.
Boron (B) is significantly below the target higher range and should be increased.

Additionally, the base saturation percentages for Potassium (K), Magnesium (Mg), and Hydrogen (H) are below the target higher range and should be increased, while Calcium (Ca) and Sodium (Na) are within the target higher range.

Based on this comparison, your soil has deficiencies in phosphorus, potassium, magnesium, sulfur, manganese, copper, and boron. To improve your soil fertility and nutrient balance, consider using appropriate fertilizers and soil amendments that align with the specific deficiencies identified in the soil test.

Remember, the goal is to create a balanced and nutrient-rich soil to support healthy plant growth and overall garden productivity. Regular soil testing and adjustments will help you achieve these targets and create an optimal environment for your plants.

Here is the data from the Soil Test Labs recommendation on how much to apply.
Data is given in lbs/ac. Lime 11000, N 35, P205 65, K20 35, Mg 10, S 20, B 2

Thank you for providing the soil test lab’s recommendations for how much to apply in lbs/ac (pounds per acre). These recommendations aim to address the specific nutrient deficiencies and pH level of your soil to improve its fertility and support healthy plant growth. Let’s review the recommended application rates:

Soil Test Lab Recommendations (lbs/ac):

Lime: 11000 lbs/ac (lime is used to adjust the pH of the soil; this high rate may indicate that your soil is acidic and requires significant lime application to raise the pH)
Nitrogen (N): 35 lbs/ac
Phosphorus (P205): 65 lbs/ac
Potassium (K20): 35 lbs/ac
Magnesium (Mg): 10 lbs/ac
Sulfur (S): 20 lbs/ac
Boron (B): 2 lbs/ac

These application rates are specific to an acre of land and are provided based on your soil test data and the target nutrient levels. Applying the recommended amounts of lime and various nutrients will help bring your soil closer to the desired nutrient levels and pH, which, in turn, can promote better plant growth and overall soil health.

Please note that the application rates may vary depending on the specific crops you plan to grow, the type of soil you have, and other environmental factors. It’s essential to follow the lab’s recommendations closely and, if needed, consult with local agricultural experts or extension offices for further guidance tailored to your region and specific gardening goals.

Applying the right nutrients in the correct amounts will help you create an ideal growing environment for your plants and maximize their potential. Regular soil testing and adjustments based on the test results will help you maintain a balanced and healthy soil over time.

Nigel Kay

I grow food, plant trees, maintain orchards, and design ecosystems that help families become healthier and happier.