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Chlorine (Cl)
This micronutrient is essential for photosynthesis, where it acts as an enzyme activator during the production of oxygen from water....
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Chlorosis
The condition of a sick plant with yellowing leaves due to inadequate formation of chlorophyll. Chlorosis is caused by a nutrient deficiency, usually iron or nitrogen; nutrient deficiencies are themselves...
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Clone
A plant produced through asexual reproduction including, but not limited to, cuttings, layering and tissue culture....
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Conditioning
To soak new Rockwool in an acidic solution to lower the ph from 8.0 to 5.5....
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Copper (Cu)
This micronutrient is an internal catalyst and acts as an electron carrier; it is also believed to play a role in nitrogen fixation....
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Damping-off fungus
Disease that attacks young seedlings and cuttings, causing stems to rot at the base; overwatering is the main cause of damping-off....
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Dissolved solids or total dissolved solids
The amount of dissolved solids, usually fertilizer salts, that are measured in water in parts per million....
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Drip aeration
A hydroponic method wherein air pressure from a small air pump is used to percolate nutrient solution out through a ring of feeder tubing which encircles the plant....
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Drip system (drip emitter system)
A very efficient watering system that employs a main hose with small water emitters. Water is metered out of the emitters, one drop at a time....
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Ebb-and-flow (or flood and drain)
A hydroponic system in which the medium, usually aggregate pebbles, is periodically flooded with nutrient solution and then drained again, feeding and aerating the medium and root system....
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Foliar feeding
Misting plants with fertilizer solution, which is absorbed by the foliage....
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My water is chlorinated — is this a problem?
Chlorine is highly volatile; it evaporates as soon as it hits the air. By the time the nutrient solution reaches the roots, the chlorine is gone....
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I understand the roots also need oxygen. How do they get it?
In a properly functioning hydroponic unit, the roots receive oxygen from the air, which surrounds them, as well as from the oxygen, which is dissolved in the nutrient solution. The...
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What about water temperature?
Temperature of the nutrient solution should be in the range of 65 to 80 degrees Fahrenheit (18 to 26 degrees Celsius). Before adding water to your reservoir, it is a...
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What is the best way to calibrate a TDS or EC meter?
Standard reference solutions are used. The bottles are marked with the conductivity (EC) value in milliSiemens/cm and the corresponding ppm values for sodium chloride (NaCl) and potassium chloride (KCl) solutions,...
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What does a TDS or EC meter measure?
The electrical conductivity (EC) of your nutrient results from motion of mineral ions when the meter applies an electrical voltage. The ppM value of a sodium chloride solution happens to...
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What does the term Parts Per Million (PPM) mean?
It is a common unit for measuring the concentration of elements in the nutrient solution. One ppm is one part by weight of the mineral in one million parts of...
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How do I convert between TDS and EC readings?
To obtain an approximate sodium chloride TDS value, multiply the EC reading (in milliSiemens/cm) by 1000 and divide by 2. To get an EC value, multiply the ppm reading by...
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Is it better to use an EC or a TDS meter?
If you have plant nutrient recommendations in EC units, an EC meter is convenient. If your plant nutrient recommendations are in ppm values, a sodium chloride TDS calibration is easier...
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Using the 3-2-1 FloraSeries® mixture, approximately what TDS or EC readings should I expect?
NutrientEC (milliSiemens/cm)TDS meter (NaCl standard)3:2:1 2.3-2.5 1350-1450 2:2:2 2.2-2.4 1300-1400 1:2:3 2.1-2.3 1250-1350...
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Why is conductivity of the nutrient important?
Conductivity is a measure of the strength of the nutrient solution. The higher the conductivity, the more dissolved solids there are in the solution. Delicate plants, cuttings, and seedlings can...
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How does conductivity affect plant growth?
Conductivity is really a measure of the nutrients in the solution. Low conductivity implies a low nutrient concentration, which usually results in nutritional deficiencies and slow growth rates of your...
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How does fresh air affect plant growth?
Ventilation is often overlooked as a problem. Plants absorb nutrients when the water molecules in the leaves respire (i.e. evaporate). Better ventilation aids a high transpiration rate, which translates into...
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Can you explain pH in a little more detail?
pH is a measure of the hydronium ion H3O+. It is based on a logarithmic scale from 0 to 14. “Pure” water has a pH of 7.0. If the pH...
