Sample Information

This section contains sample information provided by the client, including sample identifier, description of intended use, media use code, and grower comments.

Nitrogen

This section reports the total concentration of inorganic nitrogen and the individual concentrations of inorganic nitrate-nitrogen (NO3-N) and ammonia-nitrogen (NH4-N), which sum to the total inorganic nitrogen concentration. Results are reported in parts per million (ppm) which is equivalent to mg/kg.

Other Plant Nutrients

Concentrations of  phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), manganese (Mn),  zinc (Zn), copper (Cu), and boron (B) are reported in parts per million (ppm) which is equivalent to mg/kg.

Sodium, Chloride and Aluminum

Sodium (Na) and chloride (Cl) are elements that may be important for plant nutrition but are more often detrimental to plant health in excessive levels. Aluminum (Al) is not a plant nutrient and may create toxicity when media substrate pH is excessively low.  Aluminum also plays a role in coloration for ornamental crops such as hydrangea.

Other Parameters

EC (Electrical Conductivity) is reported in units of mS/cm. It  measures the total quantity of dissolved salts (ions) in the growing media. It may be used as a general evaluation of the total nutrient concentrations available to plants. However, it also includes elements such as sodium (Na) and chloride (Cl), which increase EC without providing nutritional value. In addition, excessively high EC will burn plant roots regardless of  whether the ions are required for plant nutrition.

SS (Soluble Salts) is the same as EC, but is expressed in units of 10-5 S/cm.

pH is the level of acidity or basicity as measured by the amount of hydrogen ions (H+ ) in solution. It ranges from 0 (acidic) to 14 (basic) on a logarithmic scale; 7 indicates neutrality. It can reduce the availability of micronutrients (Fe, Mn, Zn, Cu,B) when pH is high (>6.5) and the availability of macronutrients (N, P, K, Ca, Mg, S) when pH is  low (<5.0). It also impacts the efficacy of pesticides. 

Bulk density (BD) is a measure of how heavy the soilless media is, relative to its volume. It is an optional test that is often used to determine pesticide application rates.

Nutrient Ratios and Balances

Nutrient Ratios indicate the balance between nutrients that are known to affect nutrient uptake when one element is at excessively high concentrations relative to the other. The nutrient ratios reported are potassium:calcium (K:Ca), calcium:magnesium (Ca:Mg) and potassium:magnesium (K:Mg).

Nutrient Balances  are expressed as a percentage of total soluble salts (EC). When the total salts in the growing media are comprised of excessively high concentrations of one nutrient, this can induce deficiencies of other nutrients. Also, when salts such as sodium (Na) and chloride (Cl) make up an excessive percentage of the total salts, plant damage is more likely.

Agronomists Comments

If the client provides information on the submission form regarding the intended use of the growing media, an NCDA&CS agronomist will review the results, point out any parameter value that may be detrimental to the intended use, and offer suggestions for management. 

This page was last modified on 09/27/2024