Sample Information

When you collected your soil samples, you should have given each sample a unique sample ID to help you remember where you collected that sample. For example, a sample collected from your front yard could be given the sample ID, FRONT. In the example below, the first sample was given the Sample ID of 61769.


Test Results

The following test results are given for each homeowner sample:

  1. Soil pH, which is a measure of the soil's acidity.  The soil pH for your sample can be compared to the graph that shows the optimum pH range for the crop that you are growing.
  2.  Phosphorus Index (P-I) indicates the level of phosphorus found in the soil. Compare your sample's P-I to the optimum range (50 to 70) shown on the graph.
  3. Potassium Index (K-I) reflects the level of potassium found in the soil.  Compare your sample's K-I to the optimum range (50 to 70) shown on the graph.

In the example below, the sample ID = 61769. For this sample, the pH is 6.6 and is very near the optimal range.  The P-I is 24 (low P) and the K-I is 76 (high K).  The manganese, zinc, and copper indices are all very high. Sulfur has an index of 48 (medium).

The optimum soil pH depends upon the type of plant that you are growing. Some plants like azaleas and blueberries prefer acidic soils (pH 5.0 to 5.5) while most vegetable and field crops grow optimally with a soil pH of 6.0 to 6.5.


Plant Type Optimum Soil pH
Azalea, rhododendron, camellia, mountain laurel 5.0–5.5
Most shrubs and shade trees 6.0
Fescue, bermudagrass, zoysia, St. Augustine grass 6.0–6.5
Centipede grass 5.5
Rose 6.5
Berries and most fruit trees, except blueberries 6.0–6.5
Most vegetable and field crops 6.0–6.5
Tomato 6.5

Lime and Fertilizer Recommendations

Lime recommendations are given as pounds of lime to be applied per 1,000 square feet.

Application of lime at the recommended rate will raise soil pH to the optimum range for two to three years, depending upon soil type.  Lime can be applied at any time of year, but because it reacts slowly, it is best to apply it several months before a new planting. Mixing lime in with the soil helps to speed up the reaction time. 

Fertilizer recommendations are given as pounds of fertilizer to be applied per 1,000 square feet. If soil test P-I and K-I values are adequate (>50), a fertilizer containing only nitrogen is recommended. A mixed (N-P-K) fertilizer is recommended if P-I or K-I values are less than optimum. Fertilizers containing Nitrogen should be applied at beginning or during the growing cycle of the plant.

In the example below, lime is not recommended (0.0 lb. per 1,000 square feet) since soil pH is in the optimum range. 

A 5-10-10 fertilizer is recommended to be applied at a rate of 20 pounds per 1,000 square feet because results indicate that your soil had a low amount of P but a high amount of K.  If a 5-10-10 fertilizer cannot be found, then you can choose another Group B fertilizer, but you will need to adjust the rate accordingly. See the table below that lists equivalent fertilizers for Groups A, B, C, and D.

Fertilizer Equivalency Table


Additional Results

  1. Soil Class - mineral, organic, or mineral-organic.
  2. HM% is the percentage of humic matter found in your sample. HM% represents the portion of soil organic matter that is chemically reactive.
  3. W/V is the bulk density of the soil and is a good indicator of soil texture. Very sandy soils often have a W/V more than 1.5 g/cm3 while silt and clay loams tend to be near 1.0g/cm3.
  4. CEC is the cation exchange capacity of the soil and indicates the extent to which a soil can hold certain positively charged nutrients such as calcium, magnesium, and potassium. In general, the higher the CEC, the better is its ability to retain nutrients.
  5. Mn-I (Manganese Index), Zn-I (Zinc Index), Cu-I (Copper Index), and S-I (Sulfur Index).

Additional Test results

Agronomist's Comments

This area of the report provides additional information to help you understand the lime and fertilizer recommendations.  


When to Apply Lime and Fertilizer

Useful References

Page 2 useful references - This area may have helpful references listed for the specific crop you are trying to grow or additional information that helps to explain what your results mean. These references can also be found here

This page was last modified on 11/30/2023