Rock wool is a furnace product of molten rock heated to a temperature of about 1600 °C, through which a stream of air or steam is blown. More advanced production techniques are based on spinning molten rock on high speed spinning wheels, somewhat like the process used to prepare cotton candy. The final product is a mass of fine, intertwined fibres with a typical diameter of 6 to 10 micrometers.

Rock wool products can hold large quantities of water and air that aids root growth and nutrient uptake in hydroponics; their fibrous nature also provides a good mechanical structure to hold the plant stable. The high natural PH of Rock wool makes them initially unsuitable to plant growth and requires “conditioning” to produce a wool with an appropriate, stable PH.

The electrical conductivity (EC) of your nutrient, results from motion of mineral ions when the meter applies an electrical voltage. The PPM or Total Dissolved Solids (TDS) value of a potassium chloride solution happens to be very close to half of its conductivity value(in microSiemens/cm). PPM (parts per million) 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 solution.

When using a meter to measure either the PPM of total dissolved solids or conductivity of a liquid, it is necessary to periodically calibrate the meter using a calibration standard solution. There are, however, special considerations to be given to each type of calibration. Whereas conductivity is an absolute measurement with calibrations that are transferable from one type of solution to another, PPM , total dissolved solids calibrations are specific to one type of dissolved solids solution and must not be transferred from one type of dissolved solids solution to the next. Doing this will result in some serious errors in measurement.

Although the basis for testing PPM of total dissolved solids is the conductivity of the solution, it is not correct to assume that this measurement is absolute. It is always necessary to calibrate all total dissolved solids meters with a parts per million total dissolved solids standard calibration solution that contains the same type of salts or mixtures of salts as the solution to be tested. This is because total dissolved solids meters are calibrated by correlating the conductivity of the solution to the ppm dissolved solids and this correlation varies considerably from one species of dissolved solids to the next.

Most pre-formulated parts per million total dissolved solids standard calibrated solutions are formulated with calcium carbonate (CaCO3), sodium chloride (NaCl), potassium chloride (KCl), or the 442 (40% sodium sulfate, 40% sodium bicarbonate, and 20% sodium chloride) natural water formulation. If your test solution’s major dissolved solids components are the same as any of these, you may want to choose the pre-made formulation that best approximates your test solution. Generally, CaCO3 is used for boiler waters, NaCl is used for brines, and the 442 formulation is used for lakes, streams, wells, and boilers. Alternatively, if the contents of the PPM standard calibration solution used for calibration are known, it is possible to cross reference from existing calibration curves to curves for different types of dissolved solids solutions. Curves and tables are available in various reference books.

The previous discussion and references are based on standard conditions of temperature 77 Farenheight (25 deg C). When measuring conductivity or total dissolved solids in other than standard conditions, certain corrections for these variations must be accounted for before going on to determine the final values of conductivity and total dissolved solids. Without some sort of correction for standard temperature, conductivity or total dissolved solids measurements at various temperatures are meaningless because they cannot be compared. Many meters overcome this by incorporating temperature sensing elements and temperature sensing circuitry into the meter so that the value given is corrected for standard temperature. Using a meter that does not have temperature compensation will require the operator to use look-up tables or formulas to correct for the temperature effect.

One more thing to consider is the relative cleanliness of your TDS or EC electrode. A polarized or fouled electrode must be cleaned for renewal of the active surface of the cell. To prevent damage, abrasives or sharp objects should not be used. In most situations hot water with a mild detergent is effective, however acetone removes most organic matter and chlorus solutions are good for algae, molds, and bacteria.

pH is the scale of measurement of acidity or alkalinity in aqueous (water based) solutions. A neutral solution such as pure water has a pH of 7. Solutions with a lower pH are termed acidic and solutions with a higher pH are termed alkaline. PH ranges from highly acidic pH 0 to highly alkaline pH 14.

PH was introduced by a Danish biochemist named Soren Peter Lauritz Sorensen in 1909 to measure the acidity of water in the brewing of beer. The letters PH are an abbreviation for pondus hydrogenii (translated as potential hydrogen), thus meaning hydrogen power as acidity is caused by a predominance of hydrogen ions (H+).

Water is known as H2O, this calculates to two hydrogen atoms and one oxygen atom. Water is a polar molecular with the oxygen atom in the middle and the hydrogen atoms at the tips. This comes about because of the way the 8 negatively charged electrons in oxygen pack themselves in close to the 8 positively charged nucleus of the oxygen atom. The nucleus of an atom is very small. The Hydrogen atoms at the tips have more positive charge than negative charge and the oxygen atom has more negative charge than positive charge. This causes the molecule to be polar, that is to have an electrical field difference along it.

Water dissociates (breaks up) into H+ and OH- ( H2O < == > OH- + H+). The energy of the atoms bumping into each other cause the water molecules to split up. Because water is a polar molecule the H+ will attract the negatively charged Oxygen atoms in other water molecules and will “float” away. The OH- will attract the Hydrogen in other water molecules and float away on its own. Eventually a H+ and a OH- will bump into each other and join up to become water again. This process of dissociation and association is dynamic.

In pure water, for every one H+ There are 10,000,000 normal water molecules. This is 1 in 107 and the PH of pure water is 7 meaning for every 107 molecules of water there is a H+ ion.

Said in another way the H+ concentration is 10-7 parts (pH of 7), that is one part in 10Million parts. Likewise with the OH-. If the amount of H+ increases by adding acidic compounds (hydrochloric acid HCl < == > H+ and Cl-) then there are more H+’s to combine with OH-‘s so the concentration of OH- is reduced. Likewise adding OH- by adding an alkaline compound (Caustic Soda NaOH < == > Na+ and OH-) reduces the concentration of H+. A Chemical rule is that the concentration of H+ times the concentration of OH- always equals 10-14.

Low PH (acidic) conditions cause water to be corrosive. Acids will cause pitting of concrete, dissolve metals, wrinkle vinyl, irritate skin and eye and stains pool and spa walls and pipes.

High PH (caustic) conditions cause scaling – minerals precipitate out of the water (calcium, copper, iron etc.); and those minerals will block filters and pipes.

The numerical value of the PH is the negative of the exponent of the molar concentration. A mole is defined as the weight in grams that corresponds to the summed atomic weights of all the atoms of a molecule – its molecular mass. In the case of H+ the molecular mass equals 1, and a mole of H+ ions would weigh 1 gram. In the case of water (H2O) the molecular mass equals 34, and a mole of water ions would weigh 18 grams (The sum of the atomic weights).

Thus low PH values indicate high concentration of H+ ions (acid), and high PH values indicate low concentrations. Each PH unit downward represents, therefore, a tenfold increase in the H+ concentration. A PH of 3, for example, indicates a 10-3 molar concentration of hydrogen ions. To put it simply the PH scale is logarithmic, meaning that every PH unit means “10 times”. Therefore a PH of 6 is 10 times more acidic than a pH of 7, and a pH of 3 is 1000 times more acidic than 6 and 10,000 times more acidic than 7.

Combining an acidic compound with an alkaline compound produces a salt. Sodium Hydroxide plus Hydrochloric acid when mixed will become very hot and result in a salt – Sodium Chloride. Salts by themselves can increase the rate of corrosion and mineral precipitates.

Some salts give water the ability to resist changes in PH or buffer the water from wild PH swings. In water that contains no buffering ability, the PH can wander dramatically with the addition of small amounts of acids or bases (alkali), or other PH altering agents like chlorine or bromine. With a buffer the PH will hold steady and PH bounce will be eliminated for a while until so much acid or alkaline has been added that the buffering effect is overwhelmed.

The ratio in uptake of anions (negatively charged nutrients) and cations (positively charged nutrients) by plants may cause substantial shifts in PH. In general, an excess of cation over anion leads to a decrease in PH, whereas an excess of anion over cation uptake leads to an increase in PH. As nitrogen (an element required in large quantities for healthy plant growth) may be supplied either as a cation (ammonium – NH4+) or an anion (nitrate – NO3), the ratio of these two forms of nitrogen in the nutrient solution can have large effects on both the rate and direction of PH changes with time. This shift in PH can be surprisingly fast.

Daylight photosynthesis produces hydrogen ions which can cause the nutrient acidity to increase (lowering the PH). At dusk photosynthesis stops and the plants increase their rate of respiration and this coupled with the respiration of micro organisms and the decomposition of organic matter uses up the hydrogen ions so the acidity of the solution tends to decrease ( PH rises )

Most varieties of vegetables grow at their best in a nutrient solution having a PH between 6.0 and 7.5 and a nutrient temperature between 20 and 22 degrees celcius or 68 to 71 farenheight.

In low light ( overcast days or indoor growing environments) plants take up more potassium and phosphorous from the nutrient solution so the acidity increases (PH drops). In strong intense light (clear sunny days) plants take up more nitrogen from the nutrient solution so the acidity decreases (PH rises).

How pH Affects Plant Growth

• PH can affect the availability of nutrients.

• PH can affect the absorption of nutrients by plant roots

• PH values above 7.5 cause iron, manganese, copper, zinc and boron ions to be less available to plants.

• PH values below 6 cause the solubility of phosphoric acid, calcium and magnesium to drop.

• PH values between 3 and 5 and temperatures above 26 degrees Celcius or 78 Farenheight, encourage the development of fungal diseases.

• For plant roots to be able to absorb nutrients, the nutrients must be dissolved in solution. The process of precipitation (the reverse of dissolving) results in the formation of solids in the nutrient solution, making nutrients unavailable to plants. Not all precipitation settles to the bottom of the tanks, some precipitates occur as very fine suspension invisible to the naked eye.

Plants can tell us their problems through leaf symptoms (e.g. iron [Fe] deficiency) when it’s too late. Iron (Fe) is one essential plant nutrient whose solubility is affected by PH which is why it is added in a chelated form (or daily), Fe deficiency symptoms occur readily. At PH values over 7, less than 50% of the Fe is available to plants. At PH 8.0, no Fe is left in solution due to iron hydroxide precipitation (Fe(OH)3 – which eventually converts to rust). As long as the PH is kept below 6.5, over 90% of the Fe is available to plants.

Varying PH of summer lettuce nutrient solutions also affects the solubility of calcium (Ca) and phosphorus (P). Due to calcium phosphate precipitation (Ca3(PO4)2) the availability of Ca and P decreases at PH values above 6.0. All other nutrients stay in solution and do not precipitate over a wide PH range. Poor water quality could exacerbate any precipitation reactions that may occur.

Generally in the PH range 4.0 to 6.0, all nutrients are available to plants. Precipitation reduces Fe, Ca and P availability at PH 6.0 and over.

A pH meter is simply a device which measures the voltage from the electrodes and converts it to a pH reading on a display.

PH meters must have two calibration controls, which are adjusted when the pH electrode is immersed in pH buffers (solutions of a known pH which are resistant to pH change).

The first control, usually labelled CALIBRATE (also ISO, ZERO, ASYMMETRY), is used to calibrate the zero point of the electrode. This is done in a pH buffer at or near PH 7. Instruments within Australia buffer at pH6.88. This calibration must be done first.

The second calibration point calibrates the slope of the electrode. This is usually labelled SLOPE (also SPAN). In order for this calibration step to be effective, it must be done at least 2 to 3 PH away from 7. Instruments within Australia buffer at PH4.00. This calibration must be done second.

Micro-processor based instruments calculate the asymmetry and slope regardless of which buffer they are calibrated in, so it is not necessary to calibrate at 7 and then at 4.

The frequency of calibration varies from application to application. As a guideline, calibration should be checked at least weekly.

Factors that affect the output of pH electrodes include temperature changes, a blocked reference junction, and coatings on the PH glass.

Temperature effects can be compensated for in two ways. Firstly, the PH meter can have a manual control which can be set to the temperature of the solution. Secondly, the PH meter can be fitted with an Automatic Temperature Compensation (“ATC”) probe, which, as the name suggests, measures the temperature and automatically compensates for the temperature effect on PH electrode performance.

You can reposition oscillating fans, add Co2 airlines to more oscillating fans or increase Co2 flow rate if growth rate is uneven or if some plants need more Co2. Usually growers become very enthusiastic about adding Co2 at this point since they can see how it is helping their gardens. If little or no effect on growth is seen, check growing conditions for limiting factors. High garden temperatures, poor air movement, bugs, disease or incorrect nutrient mix all interfere with Co2 uptake and growth.

The Co2 generators we use for carbon dioxide enrichment are very efficient burners of propane or nautral gas. By completely oxidizing the fuel, the generator gives off pure carbon dixoide and lots of heat as water vapor! Growers planning to install Co2 generators in their gardens should antipate having to deal with excess heat and humidity from their new equipment. We approach this problem a number of ways.

One method involves placing the generator in a remote location and moving the Co2 through ducting to the air intake where it is delivered to the crop by oscillating fans. A fan attached to the duct draws the Co2-rich air from the generator, helping to dissipate heat and causing some of the water vapor to condense inside the duct. Catching condensation run-offs will help in removing condensation from the duct. Do this by sloping the duct slightly and placing a tray or bucket at the end.

Another method is to suspend the generator over-head, above the garden, and use timers or controls systems to supply Co2 for brief periods during the light hours. With all fans shut off, the Co2 generator goes on and carbon dioxide drifts downward onto the garden. When the generator shuts off by timer or thermostat, the fans are turned back on to cool the garden.

The disadvantages of this method are:

• Periods of high temperatures in the garden with no air movement.

• Limited amount of Co2 supplied to the garden

• Excess humidity levels in the garden

Cloning is a method of taking a cutting (a branch or growing portion of the plant, generally with some small leaves to aid growth) of one plant, placing it in a medium, and forcing it to take on roots of its own through the use of rooting hormones. This cutting then becomes a plant of its own but retains identical properties to the plant from which the clone was taken.

Cloning gives the grower the ultimate level of control over the growing process because, unlike seeds, the grower knows what the plant will grow to in the end. Cuttings retain the DNA of the parent plant, so by selecting plants that are most productive, disease resistant, and most healthy the grower can insure a uniform garden of only the best plants.

Growing from seeds is another matter altogether, for more than 30-60% of seeds grow up to represent the worst characteristicss of their species. Seeds also take more time to start and grow; with clones you start with a prebuilt plant and the only requirements after cutting is the application of rooting hormones and regular plant maintenance.

The first consideration when cloning a plant is the selection of a viable parent plant from which to take the clones. This plant should be at least 2 months old and exhibit the positive characteristics you desire in the finished plant. The next thing that is needed is a rooting hormone. Rooting hormones are available in liquid, powder, and gel forms. You see, when a plant is cut the wounding at the cut edges stimulates some cells to start dividing and continue to grow but in an unstructured manner, giving rise to globs of tissue called calluses (singular = callus). You can see callus formed naturally on the cut base of a carrot, cauliflower, or cabbage kept for a few weeks in the cupboard. The callus cells have lost many of the specialized features that their parent cells had in the plant. The addition of plant growth hormones to these callused areas causes many areas on the callus to begin the formation of tiny shoots. Gel-type rooting hormones are the preferred choice of growers as they remain on the cutting in an evenly distributed manner providing for better stem penetration and consistent results.

You will also need a piece of screen or shade cloth if necessary to protect your clones from intense light for their first few days. New Clones are exceedingly sensitive to light for their first few days (until they begin to form roots). They will also require foliar feeding via a water spray bottle. In their first few days it is critical that you spray the leaves of your clones with water about 4-5 times a day to supply the water that is unable to be supplied by the roots. Just spray with a fine layer of mist to keep the leaves from dehydrating. Use of a starter tray and a humidity dome can help you to keep your plants moist with less frequent spraying.

Also needed is an extremely sharp, sterile razor blade to cut your clipping and remove excess foliage, a glass of fresh, lukewarm water, a container(filled with the planting mix or grow medium of your choice in which to transfer your new clone). If your growing medium does not already have a hole, you will need to make one with a pencil, etc. to receive your clone. You are now prepared to take your first clone.

Cloning a plant is a very simple process! As stated above, you will need a sterile razor blade, cloning hormone, some lukewarm water, and your final, prepared growing medium. Rockwool cubes will need a hole, and should be pre-soaked.

1. After selecting the plant and preparing the materials per the above instructions, select which shoot you would like to clone. The ideal shoot will be 2″-4″ long and have some leaves to provide photo synthesis during rooting.

2. Remove the bottom two leaves. Cut the stems off at an angle closely to the main stem. A 45° angle insures a larger surface area for the forming of caluses that roots grow from.

3. Cut the main stem directly below the area where you’ve removed the two leaves. Once again, cut this stem at a 45° angle.

4. Apply rooting hormone to and above the fresh cut area, per the instructions on the package.

5. If you are growing your plant in soil it is a good idea to place the shoot in some lukewarm water until you see the roots begin to form. When they are 1 1/2″ – 2″ long the plant will be ready to transplant into the soil.

6. If you are using rockwool or other hydroponic media, move the plant directly into your preferred grow media directly after applying the rooting hormone.

7. Humidity, warmth and low-level light (like fluorescent) are essential to rooting plants. A seed starter tray and humidity dome are a good way to provide an acceptable cloning environment. In a cooler environment, a propagation heat mat can do the job of keeping your shoot’s rooting area at 75°-80° Fahrenheit.

8. If you are using the above method during rooting then you will need to keep your rockwool cubes moist, however not thoroughly soaked. Depending on how fast your plants use the water, and how fast the water evaporates, you may need to water your plants up to several times a day. A light fungicide such as hydroguard won’t hurt.

9. If the last two steps sound a bit daunting, you could always go with the sure-fire method of using an automatic cloning machine. With the Cloning Systems you will get much better success rates and much faster rooting times. Just stick the clone in the machine while it sprays cloning solution in a finely oxygenated mist directly onto the freshly made cuts.

To determine the appropriate lighting (and the lamp to be best used), the specific needs of the plant need to be determined. To arrange optimum lighting, the lighting present in the plant’s natural environment need to be imitated. Of course, the bigger the plant gets the more light it requires; if there is not enough light, a plant will not grow, regardless of other conditions.

For example vegetables grow best in full sunlight, which means in practice that as much light as possible must be supplied to grow vegetables indoors (fluorescent lamps, or MH-lamps are thus preferred). Foliage plants (e.g. Philodendron) grow in full shade and can therefore grow normally with relatively little artificial light (thus for the latter, regular incandescents may already suffice).

In addition, plants also require both dark and light (“photo”-) periods.Therefore, lights need to be timed to switch them on and off at set intervals. The optimum photo/dark period depends specifically on the species and variety of plant (some prefer long days and short nights and others prefer the opposite, or something in between).

For indoor gardening, one of the most important topics is light density, measured in lux. Light density is the amount of light incident on a surface. One lux equals one lumen (unit) of light falling on an area of one square meter. A brightly lit office would be illuminated at about 400 lux. In Imperial (pounds-feet) terms, a foot-candle, or the intensity of a standard candle on an area of 1 square foot, is about 10.76 lux.

In scientific terms, Kelvin temperature is a measure of the color of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (°K).

In simpler terms, it is the degree of warmth or coolness of a light source, not with regards to the physical temperature, rather to the visual temperature of the light. The higher the degree K, the more blue, or “cooler” the lamp appears. The lower the degree K, the more “warm”, or red the light appears.

Incandescent lights have a low color temperature (approximately 2700°K) and have a red-yellowish tone; natural daylight has a high color temperature (approximately 6000°K) and appears bluish. Today, the phosphors used in fluorescent and high intensity (HID) lights can be blended to provide any desired color temperature in the range from 2800°K to 6000°K.

Below you will find a brief explanation of the various artificial light sources used in horticultural applications that are available today along with the postives and negatives associated with each type.

A rating scale for light sources (lamps) from 0 to 100 to indicate how accurately colors can be perceived under a light source. The higher the CRI, the more accurately colors appear. Technically, CRI ratings should only be compared for lamps with similar color temperatures (Kelvin ratings).

Water quality is an important determinative factor in hydroponics cultivation. Water is the basic ‘carrier’ in hydroponics as it dissolves and transports nutrients for plants. However, water also dissolves a lot of impurities that can be harmful to plants. These impurities cannot be easily detected visually, and it is all too easy to be misled into making wrong assumptions about the purity of water from the clarity of a sample.

Fortunately, solutions to water quality problems, in the majority of cases, are simple and do not involve complicated methods and techniques. Even small growers can use some simple and proven techniques to effectively solve their water quality problems. The types of water quality problems that growers will likely face depends on the water source from which they draw water for their hydroponics garden. Poor water quality can lead to a number of plant growth problems including stunted growth, mineral toxicity or deficiency symptoms, build up of unwanted elements in plant tissue, bacterial contamination, etc. Though causes of poor water quality are numerous and varied some of the more frequently encountered of these are

1. Chlorination

Chlorination is the most extensively adopted measure to control bacterial contamination of water supplies in cities, towns and other urban centers. In hydroponics cultivation, the use of chlorine by growers to kill pathogens in their water has caused problems in a number of instances. It was found that this happened due high levels of active chlorine in the water used to make nutrient solution. Chlorinated water sources need to be aerated in a ‘holding tank’ for 48-72 hours (depending on the initial concentration), with good ventilation during which time the active chlorine levels fall to below 1ppm, a safe level for the plant’s root systems. Chlorine in nutrient solution water is known to cause damage to several crops especially to sensitive crops such as lettuce, salad greens, strawberries and others.

2. Unwanted minerals

Water being an excellent solvent dissolves a large number of substances including minerals. While some of these are beneficial, others like sodium, for instance, are quite harmful. Plants do not require sodium and sodium chloride if present in water can cause problems even in small quantities. Sodium can be very harmful especially in re-circulating systems. Plants differ widely in their sensitivity to sodium; some plants like tomatoes can tolerate much higher levels of sodium than other plants such as lettuce. Sodium needs to be kept below 80 ppm for healthy growth of most plants, but below 30 ppm for plants such as lettuce.

Magnesium, calcium, potassium, sulfur, nitrates and trace elements such as boron, copper, manganese and zinc may be present in water from various water sources. This can be taken care of in most cases by suitably adjusting the nutrient formulas to factor in the presence of these elements thus preventing accumulation and toxicities in the water supply. The presence of trace elements can be more troublesome and may require demineralization and dilution of the water source with pure water supply when using in nutrient solutions.

3. Microbial or pathogen contamination

Water from sources such as wells, ponds streams etc. often contains organisms that should be removed before the water can be used in nutrient formulations. The most common of these ‘pathogens’ is Pythium, which can attack plants when present in sufficient spore concentration. Growers have successfully used chlorination as a line of defense against these pathogens, but it requires that the chlorinated water be held for a few days to allow to the concentration of chlorine to drop to levels tolerable to plants. Hydrogen Peroxide can also be used to kill pathogens such as Fusarium wilt and Pythium in water and nutrient solutions.

4. Iron and Iron bacteria

Iron in the form of iron hydroxide is usually present in water from ground water sources near areas with deposits of iron sand or iron ores. The iron hydroxide in water, though not directly harmful to plants presents a number of problems due to the blockages it causes in various components of the system. These blockages if not removed, from an ideal medium for growth of iron bacteria, which consume a variety of elements that are provided for plant growth in hydroponics systems. Iron hydroxide removal methods include aeration and settling or flocculation with different agents. Iron bacteria can be removed by sterilization of the water or nutrient solution.

5. Hard water sources

Water is termed ‘hard’ when it contains substantial amounts dissolved calcium bicarbonate and other elements. When in contact with pipes and equipment the calcium bicarbonate changes to insoluble calcium carbonate also known as lime scale. Hard water forms scale in irrigation pipes, heating elements and pumps causing severe blockages. Computerized water conditioner units similar to the ones used in domestic water supplies can be used to eliminate scaling problems in hydroponics systems.

6. Herbicides

Cases of herbicide contamination of ground water sources and even municipal water supplies are not unknown. Herbicide contamination manifests as damage to sensitive crops such as tomatoes. Activated carbon filtration can help reduce damage but care must be taken to replace the carbon often enough to enable it to retain its efficiency.

Summary

Pure, clean water is essential for healthy plant growth and growers can give the best start to their plants by investing some time and effort in ensuring water quality. Water quality problems are often easy to solve provided they are properly identified. The best approach is to be proactive about water quality as assumptions based on water clarity, absence of visible contamination etc. may be quite misleading.

HID light consists of a glass tube that contain tungsten electrodes, gas and metals. You see light emit from the tube when an electrical arc is struck across the electrodes. The gas helps the light to start, and once the metals are heated they function to produce the light. Gardeners enjoy the benefits of using these lights because they provide light that most closely resembles sunlight, a definite plus when you are growing plants indoors without exposure to sunlight. They are also cost efficient, because they last longer than other light bulbs and are more energy efficient.

The ballast is used to start the lamp and to allow the electricity to continue flowing through the bulb to keep the light on. The ballast’s function is to control the electrical current running through the glass bulb so that there is just enough current flowing through so that the light ignites and is maintained, but not so much that the bulb is destroyed. Having said that, it is clear that you must use a ballast when you want to run your HID lights in order to control the electrical current; otherwise, they will not work properly.

There are three different types of ballasts that are used with high intensity discharge lights, and they include magnetic ballasts, electronic ballasts, and digital ballasts. A magnetic ballast is also called a core and coil ballast, which refers to the components inside the ballast. Along with a capacitor, they work together to control the current to ignite the light and keep the energy flowing at exactly the correct rate for the bulb. Some magnetic ballasts also come with an igniter, which are used in coordination with sodium and metal halide lamps. Electronic ballasts use electronic circuitry to control the electrical flow within the HID bulb. A digital ballast works on a higher frequency, so it produces more light but uses less energy to do so. The digital aspect of the ballast allows it to function at consistently correct temperatures, which helps the bulbs to last longer.

Lettuce and other types of greens grow well hydroponically, with minimum maintenance required. Additionally, tomatoes and peppers grow exceptionally well, but do require some maintenance and work because of their size. Flowers are great to grow hydroponically because they grow quickly and can be used to decorate your home.

Plants that develop large roots, like carrots and radishes, cannot be grown hydroponically because the soil-less growing medium cannot expand in the same way that soil does. Included in this list are plants like potatoes.

I recommend a complete change of nutrients once a week to once every two weeks. Although some argue that this is a waste of nutrients and you can just top up the reservoir when the nutrient level has gone down due to evaporation and transpiration, this may be true.

However, depending on the plants nutritional needs, it may be taking up more of certain nutrients and less of other nutrients…topping up can lead to toxic nutrient levels with some nutrients and deficiencys in others. If you consistently top up with plain pH adjusted water, eventually, the nutrient solution will become depleted of nutrients and the plants will suffer. When nutrients are first mixed..the nutrition is very balanced and for this reason I recommend changing the buckets out at least once every two weeks and preferably once a week. Be sure to scrub the buckets out well with hot water each time you change the nutrients.

If your goal is to convert soil-grown plants to an indoor hydroponic system, you’ll firstly need to wash any soil away from the roots. Do this away from any sunlight. Do it in a cool area. Then plant your roots as straight down as practicable. Roots that are upturned may slowly kill your beloved plant or, alternatively, promote disease. Transfer only young, healthy plants.

Initially, seeds or cuttings maybe raised on a bed of moistened coarse sand topped with a layer of perlite. I’ve also had great success raising seedlings in potting mix using the procedures explained elsewhere in this website.

The general rule is to plant the seed approximately under the medium to about the same thickness as the seed. Still,if rooted in perlite and sand, you can go a little deeper. Once the seedlings are ready, you can then undertake the transfer.