Test tools and kits make full use of some of the best science there is. The general principle of most of these tools and test kits is to measure particular properties of a solution. Solutions are made by combining and soil, fertilizer, organics (leaves, composts, etc.) with distilled water. Once the properties of your soil and plants are known you will have new information about the health, fertility, maturity and activity levels of your crops and soil. The glossary below explains the basics of what these devices can measure so that you can better understand how they provide valuable insights into gardening practices.
Acidity: The measure of how much acid is in a solution. Also called the “pH”, it is important to maintain proper acidity levels in order for plants to uptake nutrients properly.
Brix: Brix is a plant, not a soil, reading. A measurement of the total dissolved solids in a solution, which is an indicator of sweetness. It can be used to determine when fruits and vegetables are ripe and ready to harvest. It indicates adequate nutrition and is an excellent measurement of fertilization success. Plants with high Brix (reading above 12) sugar content are generally healthy. Used to measure sugar content (Brix) of fruits to determine maturity. Also used to monitor the Brix in plant tissue (leaves and stems) throughout the season.
Conductivity: The measure of how well electricity flows through a solution. It is directly related to the amount of dissolved minerals present and can be used as an indicator of soil fertility.
Organic Matter: The measure of all living and once-living matter that has been decomposed into simpler forms. This includes things like leaves, compost, manure, etc. Organic matter is important for maintaining healthy soils with good drainage and aeration properties.
pH – This measurement of acidity or alkalinity ranges from 1 (most acid) to 7 (neutral) to 14 (most alkaline). It is likely that your soil is in the 5 to 8.5 range. In soil, pH extremes limit biological activity, humus formation, and plant growth. Frequent monitoring is essential, as soil pH changes rapidly during fertilization, irrigation, and even the phases of the moon. Effective pH monitoring of spray solutions will maximize nutrient uptake in foliar feeds.
EC – Electrical Conductivity testing of soil gives a wealth of information: particle size and texture, drainage, cation exchange capacity [CEC] to show percentage of clay and organic matter, topsoil depth, porosity, salinity, and temperature.
ERGS – Energy Released per Gram of Soil, as defined by Carey Reams. ERGS represents the amount of energy available to the growing crops and microorganisms. For example; overall reading above 1,000 generally indicates a salt problem, energy loss and waste, and increased potential for root burn. Overall levels below 200 indicate little or no crop growth is occurring. Late–season crop finishing is directly correlated to the ERGS level.
TDS – Total dissolved solids. An expression for the combined content of all organic and non–organic substances contained in a liquid.
ORP – Oxygen Reduction Potential or available oxygen. Oxygen availability is crucial to the plant’s uptake ability. Based on ORP reading, available oxygen can be easily adjusted using hydrogen peroxide. This definitely enhances the effectiveness of foliar feeds by increasing plant ability to absorb them. ORP and pH readings together provide an “rH value,” which is used to diagnose the biological condition of your soil.
rH – Redox Value A soil rH below 25 indicates low oxygen, limited biological activity, and a consequent lack of humus–building. A soil rH over 29 indicates too much oxygen, resulting in oxidation of organic material and loss of carbon to the atmosphere, limiting nutrient availability to the crop. rH value is derived from the ORP and pH readings.. Brix – High Brix is a plant, not a soil, reading. It indicates adequate nutrition and is an excellent measurement of fertilization success. Plants with high Brix (reading above 12) sugar content are generally healthy. Used to measure sugar content (Brix) of fruits to determine maturity. Also used to monitor the Brix in plant tissue (leaves and stems) throughout the season
Reference Solutions – Are not included with most meters, although they are necessary to calibrate your meter. For pH, the 7.0 solution is the solution to use for primary calibration. If accurate readings below pH 6.0 are consistently needed, the 4.0 solution is also recommended. For best calibration and accuracy, use both the 7.0 and 4.0 reference solutions.