Hydroponics & Aquaponics

  • How to grow plants in NFT Channels?

    Growing Plants in NFT channels

    Nutrient Film Technique (NFT) growing is primarily used for growing leafy green plants. Using this method, a thin stream of water flows through a rectangular channel about 3" to 10" wide (wider channels are used for fodder crops). Because the nutrient stream forms a thin film in the bottom of the channel it gives the method its name. Plant roots are bathed in this stream of nutrients and grow very quickly.

    Hydrilla offers NFT channels in different sizes. And these channels are punched with specially sized holes to enable a grower to precisely space crops for best growth.

    When installed the channels are sloped about one inch over every thirty-six to forty inches to allow the nutrient film to flow easily. The nutrient liquid is pumped in through a small diameter feed line, flows down the channel to be collected at the lower end. At the lower end the film flows back into the reservoir ready to be reused.









    What kind of plants can be grown in NFT channels?

    NFT channels are primarily used to grow leafy green plants with a short growth period. Bibb and leaf type lettuce are an ideal plant for such a system but you can grow other leafy green plants such as spinach, broccoli, and certain herbs. Larger plants such as cabbage, that take longer to grow, are heavier, and have larger root systems are not suitable for an NFT system.

    Starting seedlings for NFT channels: -

    seedling-trays Seedling Trays

    Most hydroponic plants are started in cubes and transplanted into the channels. The cubes can be made of rockwool, coir, peat moss or a type of spun polymer that allow the nutrient film to soak the cube but also allow the film to flow past it.



    To start seedlings the first step is to wet the cubes. Run several quarts of water through the cubes. This not only wets them but also cleans out any excess salts in the cubes. set the cubes in standard seedling flats before placing a seed in the dimple in the center of the cube.

    You will find it difficult to set a single seed in the middle of each cube because the seeds are so small.

    Keep the seedlings damp and keep the temperature in the germinating area around 20 to 25°C and Keep the temperature around the seedlings at least 13-21°C at night and up to 25°C during the day. Moisten the seedlings with either water (no nutrients) or half strength nutrient solution until the plant roots reach the bottom of the cube in about ten days to two weeks.

    How to Transplant into NFT System?

    When you see roots at the bottom of the cube or when the seedling leaves are around 2" long, transplant into NFT channels and fertilize until the plants reach harvestable size. When placing cubes in the channels the slots in the bottom of the cube should run along the channel to help the nutrient film flow easily. Nutrient flow at this time should be about 2 liters per minute for large plants and 0.5 liter capacity per minute at a pH of 5 to 5.8 depending on temperature and time of year.

    Harvesting the crop: -

    To harvest the crop, the lettuce and its cube are gently lifted out of the channel. The cube can be disposed of by trimming the roots away, or it can be left in place depending on what your buyer prefers. You might also have to trim away any leaves with brown tips or discoloration. Immediately after harvesting the crop should be cooled, packed and shipped. Delays are critical to the quality of your product at this stage.

    How to clean NFT Channels?

    After each crop your NFT channels should be cleaned to prevent any pathogens moving on to your next crop.

    To clean the channels, you can make up a mixture of water with a half cup of bleach added to kill of organisms and then rinse with fresh water or you can clean with a bacterial fungicide such as Oxidate or Zerotol. By cleaning your channels regularly, you will not transport bacteria or pathogens from one crop to the next.

    Mixing Nutrients: -

    Hydroponic Nutrients Hydroponic Nutrients for Leafy greens

    If you are planning a small system, using concentrated solution is an option, but at Hydrilla we recommend using an easily dis solvable granular fertilizer. This fertilizer is based on the plant requirements only. However, if your water supply analysis tells us that your water already contains specific elements, we can change the formulation to suit your water supply. Because some fertilizer materials react together in storage, Hydrilla supplies them in separate containers for the grower to mix in separate tanks. Only after the granular fertilizer is dissolved is it mixed together.

    After mixing the nutrient solution is pumped to the upper ends of the channels allowing gravity to move it down toward the lower end. At the lower end the solution is funneled back into the reservoir. In some systems the nutrient system flows continuously, while in others it is pumped through the system every three or four hours.

  • Major Differences between Soil and Soil less crop production

    There are many similarities between in-ground soil based agriculture and soil less production, While the basic plant biology is always same. However it is worth investigating major differences between soil and soil-less production in order to bridge the gap between traditional in-ground practices and newer soil-less techniques. Generally the differences are between the use of fertilizer and consumption of water, the ability to use non-arable land, and overall productivity. In addition, soil-less agriculture is typically less labor-intensive. Finally, soil-less techniques support monocultures better than does in-ground agriculture.

    Soil vs Soil less crop production


    Soil chemistry, especially relating to the availability of nutrients and the dynamics of fertilizers, is a full discipline and fairly complex. Fertilizer addition is required for intensive in-ground cultivation. However, farmers cannot fully control the delivery of these nutrients to plants because of the complex process occurring in the soil, including biotic and abiotic interactions. The sum of these interactions determines the availability of the nutrients to the plant roots. Conversely, in soil-less culture, the nutrients are dissolved in a solution that is delivered directly to the plants, and can be tailored specifically to plant's needs. Plants in soil-less culture grow in contained inert media. These media do not interfere with the delivery of nutrients, which can occur in soil, in addition, the media physically support the plants and keep the roots wet and aerated. Moreover, with in-ground agriculture, some of the fertilizers may be lost to weeds and runoff, which can decrease efficiency while causing environmental concerns. Fertilizer is expensive and can make up a large part of the budget for in-ground farming.
    The tailored management of fertilizer in soil-less agriculture has two main advantages. First, minimal fertilizer is lost to chemical, biological or physical processes. These losses decrease efficiency and can add to the cost. Second, the nutrient concentrations can be precisely monitored and adjusted according to the requirements of the plants at particular growth stages. This increased control can improve productivity and enhance the quality of the products.

    Water Use:-

    Water use in hydroponics and aquaponics is much lower than in soil production. Water is lost form in-ground agriculture through evaporation from the surface, transpiration through the leaves, percolation into the subsoil, runoff and weed growth. However, in soil-less culture, the only water use is through crop growth and transpiration through the leaves. The water used is the absolute minimum needed to grow the plants, and only a negligible amount of water is lost for evaporation from the soil-less media. Overall, aquaponics uses only about 10 percent of the water needed to grow the same plant in soil. Thus, soil-less cultivation has great potential to allow production where water is scarce or expensive.

    Utilization of non-arable land:-

    Owning to the fact that soil is not needed, soil-less culture methods can be used in areas with non-arable land. One common place for aquaponics is in urban and peri-urban areas that cannot support traditional soil agriculture.  Aquaponics can be used on the ground floor, in basements (using grow lights) or on rooftops. Urban-based agriculture can also reduce the production footprint because transport needs are greatly reduced. Urban agriculture is local agriculture and contributes to the local economy and local food security. Another important application for aquaponics is in other areas where traditional agriculture cannot be employed. Such as in area that are extremely dry (deserts and other arid climates), where the soil has high salinity (coastal and coral sand islands) where the soil quality has been degraded through over-use of fertilizers or lost because of erosion or mining, or in general where arable land is unavailable owing to tenure, purchase costs and land rights. Globally, the arable land suitable for farming is decreasing, and aquaponics is one method that allows people to intensively grow food where in-ground agriculture is difficult or impossible.

    Productivity and yield:-

    The most intensive hydroponic culture can achieve 20 - 25 percent higher yields than the most intensive soil-based culture, although rounded down data by hydroponic experts claim productivity 2 - 5 times higher. This is when hydroponic culture uses exhaustive greenhouse management, including expensive inputs to sterilize and fertilize the plants. Even without the expensive inputs, the aquaponic techniques described in this publication can equal hydroponic yields and be more productive than soil. The main reason is the fact that soil-less culture allows the farmer to monitor, maintain and adjust the growing conditions for the plants, ensuring optimal real-time nutrient balances, water delivery, pH and temperature. In addition, in soil-less culture, there is no competition with weeds and plant benefit from higher control of pests and diseases.

    Reduced Workload:-

    Soil-less culture does not require ploughing, tilling, mulching or weeding. On large farms, this equates to lower reliance on agriculture machinery and fossil fuel usage. In small-scale agriculture, this equates to an easier, less labor-intensive exercise for the farmer, especially because most aquaponic units are raised off the ground, which avoids stooping. Harvesting is also a simple procedure compared with soil-based agriculture, and products do not need extensive cleaning to remove soil contamination. Aquaponics is suitable for any gender and many age classes and ability levels of people.

    Sustainable monoculture:-

    With soil-less culture, it is entirely possible to grow the same crops in monoculture, year after year. In-ground monocultures are more challenging because the soil becomes tired, loses fertility, and pests and diseases increase. In soil-less culture, there is simply no soil to lose fertility or show tiredness, and all the biotic and abiotic factors that prevent monoculture are controlled. However, all monocultures require a higher degree of attention to control epidemics compared with polyculture.

    Increased complication and high initial investment:-

    The labor required for the initial set-up and installation, as well as the cost, can discourage farmers from adopting soil-less culture. Aquaponics is also more expensive than hydroponics because the plant production units need to be supported by aquaculture installations. Aquaponics is a fairly complex system and requires daily management of three groups of organisms. If any one part of the system fails, the entire system can collapse. In addition, aquaponics requires reliable electricity. Overall, aquaponics is far more complicated than soil-based gardening. Once people are familiar with the process, aquaponics becomes very simple and the daily management becomes easier. There is a learning curve, as with many new technologies, and any new aquaponic farmer needs to be dedicated to learn. Aquaponics is not appropriate for every situation, and the benefits should be weighed against the costs before embarking on any new venture.

    Category Soil-based Soil-less
    Production Yield Variable, depending on
    soil characteristics and management.
    Very high with dense crop production.
    Production Quality Dependent on soil characteristics and
    management. Products can be of lower
    quality due to inadequate fertilization/treatments.
    Full control over delivery of appropriate
    nutrients at different plant growth stages.
    Removal of environmental, biotic and abiotic
    factors that impair plant growth in soil (soil
    structure, soil chemistry, pathogens, pests).
    Sanitation Risk of contamination due to use
    of low quality water and/or use of
    contaminated organic matter as
    Minimal risk of contamination for human health.
    Nutrition Nutrient delivery High variability depending on the soil
    characteristics and structure. Difficult
    to control the levels of nutrients at the
    root zone.
    Real time control of nutrients and pH to plants
    at the root zone. Homogeneous and accurate
    supply of nutrients according to plants growth stages. Needs monitoring and expertise.
    Nutrient use efficiency Fertilizers widely distributed with
    minimum control of nutrients according
    to growth stage. Potentially high
    nutrient loss due to leaching and runoff.
    Minimal amount used. Uniform distribution
    and real time adjustable flow of nutrients. No
    Water use System efficiency Very sensitive to soil characteristics,
    possible water stress in plants, high
    dispersal of nutrients.
    Maximized, all water loss can be avoided.
    Supply of water can be fully controlled by
    sensors. No labor costs for watering, but
    higher investment.
    Salinity Susceptible to salt build up, depending
    on soil and water characteristics.
    Flushing salt out uses large amounts of
    Depends on soil and water characteristics. Can
    use saline water, but needs salt flush-out that
    requires higher volumes of water.
    Management Labor and equipment Standard, but machines are needed
    for soil treatment (ploughing) and
    harvesting which rely on fossil
    fuels. More manpower needed for
    Expertise and daily monitoring using
    relatively costly equipment are both essential.
    High initial set-up costs. Simpler handling
    operations for harvest.
  • Aquaponics - for a sustainable future

    The challenges and potential of aquaponics production is still an unexplored area of study in India. Aquaponics is a combined method of farming by bringing aquaculture and hydroponics together in a single system. There has been a positive change in Aquaponics farming as the popularity of the system increased in the last few years in our country.

    By 2050, the world population is estimated to increase to 9 billion. The expansive numbers of people are expecting to rely on agricultural sector including farming, fisheries, woodcrafts, and livestock. Natural calamities and crisis affect millions of people who depend on the primary sector. For reducing poverty and attaining food security, expansion of agriculture sector is the most efficacious means. Small farmers are the major contributors to the World's food, but they are the poorest people in the developing countries. 70 per cent of the people living in the rural area depends on Agriculture even today, however, one-fourth of the population find it difficult to meets their daily nutritional requirement.

    Indian farmers are exposed to many challenges resulting from low agricultural growth, sustainability concerns, and land degradation, as a large area of farmland has become infertile due to the overuse of fertilizers and pesticides. Conventional farming methods because of large usage of fertilizers for growing crops degraded the quality of the soil and local water sources. It is high time to overcome these challenges through innovative farming methods. The technological and scientific advancement in the field of agriculture has opened a new era for the design and development of modern devices for plant health monitoring. Aquaponics farming is a solution to overcome some of these challenges to an extent if the farmers are able to maintain the system with proper care and technical support.

    Although aquaponics has received considerable attention in foreign countries, Indian farmers are relatively new to this system. However, there has been a gradual increase in awareness of this system over the past few years in the country.

    Aquaponics is an integrated method of growing fishes and crops in a re-circulating system. In other words, it is an integrated system of re-circulating aquaculture and hydroponics in one production system. Water from the fish tank that contains fish excretes cycles through grow beds where plants are grown, which is nutritious for the plant's growth and plants' filter the water flowing into the fish tank to keep the fish healthy. The main elements for aquaponics are the fish tank and grow beds with a small pump that filters water between the two. The success of an aquaponics system requires proper maintaining of the plants, fish, and nutrients that gives a well-balanced and interdependent relationship. Aquaponics farming is suitable for farmers who have fewer land holdings and in areas where water is scarce. Crops grown in aquaponics have less damage and are able to grow in denser climate.

    In India, the land holdings used for agriculture are limited to less than 0.2 hectares. As a result, the small-scale agriculturists aim to maximize production within the minimum resources. Growing awareness of consumers on the excessive use of fertilizers and pesticides are leading to a trend that favours organic farming. The interest of the young generation to produce vegetables and other regional cultivations on a small scale within the available land area has further boosted the scope of organic farming. Organic farming is a concept with considerable thrust on integrated systems wherein a major part of inputs required for farming is raised within the system. Integrated farming uses wastages and sub-products of a particular cultivation for the use of other. It usually includes growing and breeding of cattle, duck, fish etc. This is a globally accepted technology and adapted to a greater extent by the Indian farming community. Within the available space that includes terrace and balconies of apartments, Indian households have started taking up aquaculture in small tanks along with vegetables in separate grow beds. The method of recycling waste water and making it available for further use has increased its demand all over this time. Integrating hydroponics (the method of growing plants without soil) and aquaculture has been given more importance in the current agricultural scenario.

    As the aquaponics system has many advantages and increases the productivity within a short time period, it has gained popularity in several states of India in recent times. State Fisheries Departments are promoting aquaponics by providing training programmes and technical support to the farmers. It is an effective means of growing food that helps to maintain sustainability, as it requires only 10 per cent of water and no use of chemical fertilizers as compared to the traditional farming method.

    Aquaponics as a commercial venture is evolving in India. People are discovering it as a promising avenue to rely upon as a dependable source of livelihood. Further, small and medium-sized units are more efficient in managing costs and realizing higher net income per unit area compared to large units. However, a variety of factors such as lack of training, inadequate technical guidance, ignorance of market pricing and uncertainties about the market demand of the product, are some of the reasons for incurring losses. These challenges can be overcome by providing technical sessions about the working of the system and by making consumers aware of the benefits of organic products. In Hydrilla workshops, apart from taking participants through Aquaponics farming methods, fish and plant health management, system design aspects, we take through the analysis of marketing strategies like identifying right crops based on market demand, direct selling to neighborhood consumers, indirect selling to wholesalers, restaurants and grocery stores.

    In general, the success of aquaponics farming relies upon the local markets, climatic and geographical conditions. An important feature of aquaponics systems is their ability to reduce the local impacts that arise from the nutrient discharges. Due to the dynamic characteristics of the aquaculture industries, it is expanding rapidly in recent times. Hence, more emphasis should be given on high productivity, intensive systems with similar low global impacts rather than focusing completely on the reduction of local impacts.

    Aquaponics has immense potential to be the forerunner in the next phase of sustainable aquaculture.

  • Soilless cultures - abundant choices

    Soilless Cultures

    Many methods of soilless culture are being used successfully. Some of the media used are peat, vermiculite, perlite, sand, pumice, rice hulls, and plastic Styrofoam. Often mixtures of these media are used in various proportions. Growing trials with various mixtures determine which proportions are most suitable to the plants in question. For example, flowering potted plants such as chrysanthemums, poinsettias, and Easter lilies and tropical foliage plants can be grown well in mixtures of peat-sand-pumice in a 2:1:2 ratio.

    Peat: -

    • Peat consists of partially decomposed aquatic, marsh, bog, or swamp vegetation. The composition of different peat deposits varies widely, depending on the vegetation from which it originated, the state of decomposition, mineral content, and degree of acidity
    • There are three types of peats: moss peat, reed-sedge, and peat humus. Peat moss is the least decomposed and is derived from sphagnum, hypnum, or other mosses.
    • It has a high moisture holding capacity (10 times its dry weight), high in acidity (PH 3.8 - 4.5), and contains a small amount of nitrogen (about 1.0%) but little or no phosphorus or potassium. Peat from hypnum and other kinds of mosses breaks down rapidly, as compared with sphagnum, and is not as desirable. Peat from sedges, reeds, and other swamp plants also decomposes rapidly.

    Vermiculite: - 

    • Vermiculite is a micaceous mineral, which is expanded when heated in furnaces at temperatures near 1093 degree Celsius. The water turns to steam, popping the layer apart, forming small, porous, sponge-like kernels. Heating to this temperature gives complete sterilization.
    • Chemically, it is a hydrated magnesium-aluminium-iron silicate. When expanded, it is very light in weight (6-10lb/ft3) (96-160 kg/m3), neutral in reaction with good buffering properties, and insoluble in water, it is able to absorb large quantities of water, 3-4 gal/ft3 (0.4-0.5 mL/cm3).
    • It has a relatively high cation exchange capacity and thus can hold nutrients in reserve and later release them. It contains some magnesium and potassium, which can be used by plants.
    • Horticultural vermiculite is graded in four sizes:-
      • particles from 5 to 8 mm in diameter.
      • regular horticultural grade, from 2 to 3 mm.
      • particles from 1 to 2 mm
      • most useful as a seed-germinating medium, from 0.75 to 1 mm.
    • Expanded vermiculite should not be pressed or compacted when wet, as this will destroy its desirable porous structure.

    Perlite: -

    • Perlite is a siliceous material of volcanic origin, mined from lava flows. The crude ore is crushed and screened, then heated in furnaces to about 760 degree Celsius, at which temperature the small amount of moisture in the particles changes to steam, expanding the particles too small, sponge like kernels, which are very light, weighing only 5-8 lb/ft3 (80-128 kg/m3).
    • The high processing temperature gives a sterile product. A particle size of 0.063-0.13 in. (1.6 - 3.1 mm) in diameter is usually used in horticultural applications. Perlite will hold three to four times its weight of water.
    • It is essentially neutral, with a pH of 6.0 -8.0, but with no buffering capacity; unlike vermiculite, it has no cation exchange capacity and contains no minor nutrients. It is most useful in increasing aeration in a mixture since it has a very rigid structure. While it does not decay, the particle size can become smaller by fracturing as it is handled.
    • A fine grade is useful primarily for seed germination, while a coarser type of horticultural grade is best suited for mixing with peat, in equal parts, for propagation or with mixtures of peat and sand for growing plants.

    Pumice: -

    • Pumice, like perlite, is a siliceous material of volcanic origin. However, it is the crude ore that is obtained after crushing and screening without any heating process. It has essentially the same properties as perlite, but is heavier and does not absorb water as readily since it has not been hydrated. It is used in mixtures of peat and sand for the growing of potted plants.

    Rice Hulls: -

    • Rice Hulls are the outer husk or shell of the rice grain. After the rice grains are dried, the outer hulls are removed in the milling as a by-product. The rice hulls are thin, feather-light, and pointed in shape similar to rice grains.
    • They do not decompose readily, lasting from 3 to 5 yr. They are neutral in pH and have no nutrients. Their smooth surface does not allow them to retain moisture. They are used in the raw state to free up heavy soils to help oxygenate the soils.
    • They can also be used as a hydroponic substrate. They are mixed with peat or coco coir, usually at 20% of rice hulls. However, most soilless mixes using rice hulls prefer to use charcoaled rice hulls. This is done extensively in the greenhouse flower industry. Rice charcoal is created by burning (smouldering) the rice hulls very slowly. After burning, their structure becomes full of tiny pores, thus increasing their water-holding capacity and capillary action. Also, in this state with their large surface area, they provide sites for beneficial bacteria and other microorganisms and therefore are an excellent soil amendment.

    Soilless mixtures: -

    Most mixtures contain some combination of sand, peat, perlite, pumice, and vermiculite. The specific proportion of each component used depends on the plants grown. The following are some useful mixtures.


    Peat: Perlite: Sand

    2:2:1 for potted plants
    Peat: Perlite 1:1 for the propagation of cuttings


    Peat: Sand 1:1 for the propagation of cuttings and for potted plants


    Peat: Sand 1:3 for bedding plants and nursery container-grown stocks
    Peat: vermiculite 1:1 for the propagation of cuttings
    Peat: sand 3:1 lightweight, excellent aeration, for pots and beds, good for azaleas, gardenias


    Vermiculite: perlite 1:1 lightweight good for the propagation of cuttings
    Peat: Pumice: Sand 2:2:1 for potted plants.


  • Potash Fertilizers: Make the right choice!

    Benefits of Potassium Sulfate for Hydroponic Gardening: -

    Potassium sulfate (K2SO4) also known as sulfate of potash, arcanite, or archaically known as potash of sulfur) is a white crystalline, non-flammable salt soluble in water. The chemical compound is commonly used in fertilizers, providing both potassium and sulfur.

    The application of "K" (Potassium) in nutrient formulae depends upon its chemical combination with other elements that affect both crop quality and yield. Since potassium fertilizers are derived from natural products, they may contain substances other than K, S, and Cl that influence plant growth. Thus, choosing the right type of potash fertilizer can be as vital as applying the right amount of potash to the crop.

    Potash fertilizers are available in two main types in which potassium is combined with either chloride or sulfate. They are sulfate of potash (SOP) and muriate of potash (MOP). Potassium sulfate and potassium chloride differ in their effects on plants. Potassium in a fertilizer exists as a neutral, acid, or alkaline salt in which the cation K+ is combined with an anion: Cl or SO4. When the plant takes up K+ ion, it also absorbs an anion to maintain electrical neutrality. Anions containing S, are incorporated in plant materials thus losing their ionic form, but Cl remains in the ionic form.

    Thus, the concentration gradient of Cl in the plant is less steep than that of the other anions. Moreover, certain crops are particularly sensitive to chlorine, and for these, the use of chloride-containing fertilizers should be avoided. Crops are also sensitive to salinity which is a serious problem particularly in an arid area; again, chloride should be avoided in such cases.

    Also, Sulphur is a major plant nutrient, and plants require a continuous and sufficient supply of sulfur of the same order as that for P. Therefore, potassium sulfate is an essential salt and an excellent source of K and S that cannot be missed from your nutrient channel.

    Most often SOP is used on high-value crops like fruits, vegetables, nuts, tea, coffee and tobacco. The fertilizer works better on crops that are sensitive to chloride, which can sometimes have a toxic impact on fruit and vegetable plants.








    Potassium Sulfate uses: -

    • Sturdy stalk and stems
    • Resistance from drought and diseases
    • Resistance from drought and diseases
    • Enhances the quality of fruit
    • Strong Roots
    • Activates enzyme reaction
    • Synthesis Proteins
    • Promotes thickness of the outer cell wall
    • Improves colour and flavour
    • Forms starch and sugar
    • Regulates water flow in cells and leaves
    • Potassium is an essential cofactor in the production of ATP
  • The Science of Hydroponic Nutrients

    The first step in Hydroponics farming is to understand the difference between soil fertilizers, and the requirements of plants. Most growers are aware of soil fertilizers such as those called by numbers 19-19-19 and 20-20-20, but what does 20-20-20 really mean?

    Does it mean 20% Nitrogen (N), and 20% Phosphorous (P), and 20% Potassium (K) is the N.P.K ratio?

    No, it's not that simple.

    It's, 20% Nitrogen (N) and 20% Phosphorous Pentoxide (P2O5) and 20% Di-Potassium Oxide (K2O). (Depending on the country of origin, these units change by continent)

    This translates to the actual % of the N.P.K as follows.

    20% Nitrogen (N), 8.8% Phosphorous (P), and 16.6% Potassium (K).

    However, a good Hydroponic nutrient contains all of these plus all the other minerals required for healthy growth. They will also be in the correct ratio to each other, according to plant type, and stage of growth, e.g. Vegetative, flowering or fruiting stage.

    The minerals required for good growth are as follows:












    There are other minerals found in plant tissue when analysed, but for our purposes, these are the main requirements for Hydroponic growing, and the ones we have to monitor.

    Hydroponics grower has to understand and make sure that the Hydroponics nutrients being used have all the above macro and micro nutrients needed by the plant in a proportion that is needed at various stages of growth.

    Take for example, the above 20-20-20 fertilizer with 20% Nitrogen (N), 8.8% Phosphorous (P), and 16.6% Potassium (K).

    Researchers have determined that a tomato plant in fruiting stage needs more Potassium than Nitrogen with N:K ratio of even 1:3. Using 20-20-20 fertilizer for tomato crop in the fruiting stage might not give the best yield when compared to a Hydroponic nutrient modified in a proportion to suit the crop need.

    Hydroponic farming gives best results only when the grower gives nutrients in the right proportion suiting crop, stage of growth, water pH, EC, climate conditions etc.

  • Signs of Plant Nutritional and Physiological Disorders and Their Remedies

    Plants are similar to us humans and animals in that when under stress from poor nutrition, our bodies suffer in growth, development, and general health. Animals show these disorders in the form of weak bones, skin discolouration, and poor weight. Plants show nutritional defects in their vigour, strength of the stems, colour of the leaves and poor yields.

    Whenever plants undergo any type of stress from environmental conditions to lack or excess of nutrients, they will express signs of disorders. Pest and diseases also cause stress and disorders within the plant.

    Symptoms of disorders within the plant may be expressed as leaf yellowing (chlorosis), browning (necrosis), burning (white colouration due to loss of chlorophyll in leaves), deformation of leaves and growing tips, and stunting of overall growth. The first thing to observe with a nutrient disorder is the location of the affected tissue.







    Leaves will, in general, show the symptoms first. If it is a root problem due to disease or lack of oxygen, examination of the roots will reveal that they are not turgid and white, but limy and brown. The plant will wilt during high light periods as the water loss by transpiration is greater than the roots ability to take up sufficient water.

    The location of symptoms on the plant is the first clue as to the cause of the disorder. Focusing on leaf symptoms, if the lower leaves are expressing yellowing, browning, or spots first, then the group of nutrients responsible for the disorder would be those of mobile elements. Mobile elements can be re translated within the plant from the lower order tissue to the younger tissues in the top of the plant. These elements include N, P, K, Mg, Zn and Mo. Initial symptoms will be a yellowing (chlorosis) followed by browning or drying (necrosis) of leaf tissue. If the symptoms appear in the young leaves at the tip of the plant, this disorder is a result of a lack of immobile elements that cannot move from the older plant parts to the growing tip. These immobile elements are Ca, B, Cu, Mn, S and Fe. To determine which of these is the cause of the disorder there are some visual keys listed below allowing you to make a number of alternative choices. Each selection narrows the possible causes in the final step, there is a single element identified.

    • It is critical to recognize any symptoms occurring at an early stage of the plants, expression of these stress clues because as the disorder goes on without correction, the symptoms expand progressing from simple yellowing spots to complete yellowing and necrosis. At that stage, it is very difficult to know the first form of symptoms as they spread throughout the plant giving it an overall chlorosis, necrosis, and deformation of tissues. In addition, as the stress becomes more severe, it will be difficult, taking a lot of time to correct it once identified. The loss of the plant's health may become permanent or event result in its death. Yields will be greatly reduced as the stress is not corrected. The stress may begin as a cause from a single element and then as it progresses, another element uptake is slowed or blocked and the plant suffers from multiple disorders. A very useful procedure when a symptom first appears is to immediately change the nutrient solution. That is, make up a new batch. At the same time, to determine the exact cause send a nutrient or tissue sample to a laboratory for analysis. Similar to soil analysis, the laboratory will give you guidelines as to what the normal leaves of each nutrient should be in the solution or in the plant and direct you to make adjustments in the nutrient solution formulation.

    Mobile Elements Deficiencies: -

    Nitrogen: -

    • Lower leaves become yellowish green and growth is stunted

    Remedies: -

    • Add calcium nitrate or potassium nitrate to the nutrient solution.

    Phosphorous: -

    • Stunted growth of the plant, a purple colour of the undersides of the leaves is very distinct and leaves fall off prematurely.

    Remedies: -

    • Add mono potassium phosphate to the nutrient solution.

    Potassium: -

    • The leaflets on older leaves of tomatoes become scorched, curled margins, chlorosis between veins in the leaf tissue with small dry spots. Plant growth is restricted and stunted. Tomato fruits become blotchy and unevenly ripen.

    Remedies: -

    • Apply a foliar spray of 2% potassium sulfate and add potassium sulfate to the nutrient solution.

    Â Magnesium: -

    • The older leaves have interveinal (between veins) chlorosis from the leaf margins inward, necrotic spots appear.

    Remedies: -

    • Apply a foliar spray of 2% magnesium sulfate, add magnesium sulfate to the nutrient solution.

    Note: - When applying foliar sprays, if in a greenhouse, avoid doing during high sunlight conditions as that can cause burning of the leaves. Apply in the early morning while the sun and temperatures are low.

    Â Zinc: -

    • Older and terminal leaves are abnormally small. The plant may get a bushy appearance due to the slowing of growth at the top.

    Remedies: -

    • Use a foliar spray with1%-0.5% solution of zinc sulfate. Add zinc sulfate to the nutrient solution.

    Immobile elements: -

    • First, the symptoms appear on the younger leaves at the top of the plant.

    Calcium: -

    • The upper leaves show marginal yellowing progressing to leaf tips, margins wither, and petioles curl and die back. The growing point stops growing and the smaller leaves turn purple-brown colour on the margins, the leaflets remain tiny and deformed. Fruit of tomatoes shows blossom-end rot.

    Remedies: -

    • Apply a foliar spray of 1.0% calcium nitrate solution. Add calcium nitrate to the nutrient solution.

    Sulfur: -

    • Upper leaves become stiff and curl down, leaves turn yellow. The stems, veins and petioles turn purple and plant growth is restricted.

    Remedies: -

    • Add potassium sulfate or other sulfate compounds to the nutrient solution. A sulfur deficiency is usually rare because it is added to the nutrient solution by use of potassium, magnesium, and other sulfate salts.

     Iron: -

    • The terminal leaves start turning yellow at the margins and progress through the entire leaf leading eventually to necrosis. Initially, the smallest veins remain green giving a reticulate pattern. Flowers abort and fall off, growth is stunted and spindly in appearance.

    Remedies: -

    • Apply a foliar spray with 0.02%-0.05% solution of iron chelates every 3-4 days. Add iron chelate to the nutrient solution.

    Boron: -

    • The growing point withers and dies. Upper leaves curl inward and are deformed having interveinal mottling (blotchy pattern of yellowing). The upper smaller leaves become very brittle and break easily.

    Remedies: -

    • Apply a foliar spray of 0.1%-0.25% borax solution. Add borax or boric acid to the nutrient solution.

     Copper: -

    • Young leaves remain small, margins turn into a tube toward the midribs in tomatoes, petioles bend downward, and growth is stunned to get a bushy appearance of the plant at the top.

    Remedies: -

    • Use a foliar spray of 0.1% - 0.2% solution of copper sulfate. Add copper sulfate to the nutrient solution.

    Note: - whenever applying a foliar nutrient spray, apply it first to a few plants and wait to apply it to all plants for about a day to be sure that no burn occurs from the spray.

    Manganese: -

    • Middle and younger leaves turn pale and develop a characteristic checkered pattern of green veins with yellowish interveinal areas. Later small necrotic spots form in the pale areas. Shoots will become stunted.

    Remedies: -

    • Apply a foliar spray of 0.1% manganese sulfate solution. Add manganese sulfate to the nutrient solution.

    Molybdenum: -

    • All leaves show a pale green to yellowish interveinal mottling. Usually progresses from the older to the younger leaves.

    Remedies: -

    • Apply a foliar spray of 0.07%-0.1% solution of ammonium or sodium molybdate. Add ammonium or sodium molybdate to the nutrient solution.
  • It's not what you eat, it's what you absorb!

    "It's not what you eat, it's what you absorb,"  a phrase that applies equally to the uptake of essential nutrients by plants. Application of an essential plant nutrient does not always mean that the plant will be able to uptake that mineral and then move it through the vascular system into the plant tissues.

    The availability of plant nutrients is in fact dictated by the form of the mineral, environmental temperature, humidity, photosynthesis, pH of the root zone, and most importantly the relative concentration of each mineral in the nutrient solution. It is the balance of these minerals that are often forgotten when growers are formulating plant nutrient recipes and adding supplements to reach specifically targeted mineral compositions.

    There is a well-known system that classifies essential plant nutrients into "macro" and "micro" categories based on their concentrations in the plant tissue. Less understood is the relationship of the electrical charge of the individual ions and how it affects their bioavailability to the plant. Ions exist as either positively charged (cations) or negatively charged (anions) depending on the balance of electrons (negative) versus protons (positive). It is the strength of the ionic charge that will affect the movement of the ions into and out of the plant. By understanding the strength of the positive or negative charge of essential plant nutrients, we can begin to comprehend the selective ion uptake mechanisms of a plant's physiology. The table below shows the elemental forms of plant nutrients and their ionic charges in the forms that are available for plant uptake.

    The movement of ions into plant roots occurs by both active and passive transport. Passive transport means that the ions are carried with the uptake of water into the plant without energy from the plant. The water movement factors that affect passive transport are temperature, humidity, photosynthesis rates, the concentration of ions in solution versus within the plant cell, and plant transpiration rates based on the stage of growth. Active transport requires energy from the plant and ion movement is determined by competition between ions based on their individual charge. The monovalent ions (single charged) are moved into the plant more easily than divalent ions (double charged), while divalent ions are taken up more easily than trivalent ions (triple charged). This means that the plant will accumulate more potassium (a monovalent ion) than calcium and magnesium (divalent ions) due to the difference in their charge. Plants typically maintain a negative interior (inside the plasma membrane) relative to the exterior. The slightly negative state of the cell interior and the environment must be maintained and, thus, is related to ion uptake. When there are more cations than anions present, the overall charge becomes excessively positive, and an increase in anions or a decrease in cation uptake occurs to restore physiological conditions. For example, an excess of ammonium (NH4+) cations decreases the uptake of potassium (K+), calcium (Ca2+), and Magnesium (Mg2+). The same relationship exists for anions - excess anions lead to a lower uptake of anions or an increase in cations to balance the cell’s charge. If nitrate (NO3-) is the major anion in excess, then the uptake of cations such as potassium (K+), calcium (Ca2+), and Magnesium (Mg2+) will increase to compensate for the overall negative charge caused by excess nitrate levels.

    Many growers give themselves labels based on the types of inputs they use in their gardens, often referring to "strict organic practices" or "sterile, mineral-based hydro". Perhaps you're the type of gardener who avoids "chemicals", or only uses "organics", but can you define these terms? What makes something truly organic? Every grower should understand what they put into their gardens and why.

    What is a chemical?

    When we use words like chemicals or chemistry, we are simply referring to the study and use of elements from the Periodic Table. The elements found in the Periodic Table are the basic atoms that make up everything on this planet and many chemicals that exist in the natural world. All Plants produce chemicals throughout their life cycle. In an organic garden, we rely on microorganisms to convert organic matter into chemical forms that are taken up by plants. Chemicals can originate from natural sources. In some respects, organic gardening is a natural way of feeding chemicals to plants.

    So, the next logical question: What is Organic?

    Chemists and physicists will tell you that nearly any compound containing carbon is organic, whether that compound is natural or not. The truth is many natural substances are not organic. For example, certain types of naturally occurring rocks are crushed to make fertilizers that contain inorganic phosphorus. Those rocks are technically inorganic, even though they were mined directly from the ground. Many gardeners and agricultural professionals use the word organic to describe fertilizers and plant products that are derived exclusively from plants and animals (manure, kelp, bone meal, etc.). By that definition of the word, Organic growers cannot use inorganic substances, even if they occur naturally.

    One thing to keep in mind: many organic garden products contain inorganic salts. Two popular examples are bat guano and seaweed extract. Because these are derived from animals and plants, they qualify for organic gardening. However, the lab analysis shows a dash of inorganic material included in the final products.

    Confused yet?

    What are Minerals?

    The Periodic Table contains (among other things) the 17 elements required for plants to live: carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, chlorine, copper, iron, manganese, molybdenum, nickel, and zinc. Many scientists and university studies give evidence that silicon should be added to that list as well. Minerals occur in nature, but they are not sourced from plants or animals. These minerals may come from crushed rocks, or they may be generated in a lab via chemical processes. When looking at basic elements and minerals, there is no difference between the crushed rock form and the laboratory derivative. It may take millions of years to accumulate rock formations, which then have to be mined and pulverized, so the laboratory version is much faster. Mining can be quite harmful to the environment, not to mention, expensive and unsafe for workers. Depending on the specific element, one method may be better suited than another for obtaining these minerals with the least environmental and budgetary impact.

    In recent years, there has been increased discussion regarding the use of high-quality or low-quality minerals in plant foods. The real difference in quality can be determined by the level of contaminants in the final product. Pure, uncontaminated elements are the same, regardless of the source. Elements and compounds that are not available to plants can bog down roots and slow nutrient absorption and availability. For the highest quality mineral plant foods, avoid contaminants and questionable ingredients.

    Reasons for using organics

    There is little argument that mineral fertilizers can more easily burn plants if used carelessly. Overfeeding is always a concern, but is less likely when using organics. Microbes and fungi must work to convert elements into plant available forms, which slows reactions in the root zone as it becomes nutrient rich. While overfeeding with organics is possible, the microbiology at work in the root zone offers a natural buffer. The flavour of organically grown tomatoes, culinary herbs, and resin-producing plants is often said to be better and more complex than crops grown with minerals. The fact is that low-quality or high-quality harvests can be grown with either mineral or organic inputs. One reason why well maintained organic gardens often produce very deep aromas and flavours is, in part, because overfeeding has been avoided.

    Reasons for Using Minerals

    We live in an age where plant chemistry and biology have been analyzed to an exacting degree. Scientists have discovered which elements are taken up by plants, and the specific ratios required for optimum performance. Mineral nutrient formulations can be made using highly available forms, allowing plants to absorb them right away. This process can lead to faster growth, bigger harvests, and increased quality. Many hobby gardeners grow delicious tomatoes in their backyards, using mineral salts from the local garden centre. Even without organics, mineral-grown crops can offer increased flavours and aromas, as long as the grower does not over-use plant foods or harvest prematurely. Attention to detail is required when using mineral fertilizers, and there is no need to sacrifice quality by overdosing plants. When given the correct amounts of mineral inputs, plants can achieve optimum health. Overall plant health is the key to both higher yield and quality.

    Hybrid Nutrient Systems

    Growers all over the world have achieved big yields and potent flavours by using organics and minerals together. Both offer unique benefits, and there is no reason you can't use them in tandem to get the best of both worlds.

    Many naturally occurring inorganic compounds are not only safe for plants, they are safe enough for you to eat! Don't reject the idea of using organics, minerals or both before doing some research on the pros, cons and effectiveness of each type of nutrient.

    What are you feeding your plants?

    Not every garden product should be assumed to be safe or effective. Learn about the elements your plants require and the additional organic inputs that offer increased quality. With a little bit of knowledge and high-quality plant nutrients whether organic, mineral, or both, your garden will flourish!


  • Seedling Culture

    • Hydroponic is the act of raising plants without using soil, but rather in a water medium with nutrients.
    • The plants are placed in a hydroponic system that supplies the required nutrients to the roots with the help of the water medium.
    • The use of hydroponic has helped farmers to evade serious seedling diseases and pests like fungus and gnats, which mostly attack in moist soils.
    • Media like coconut fibre, plugs, and peat pots have necessary nutrients and ensure that the seeds have a healthy growth.
    • Rockwool or oasis can serve as a medium, the seedlings can be transplanted along with the cube into a complete hydroponic system later.
    • Rapid rooters are mostly used as a medium as they have large numbers of important microbes and Mycorrhizal fungi that help in colonizing the root thus maximizing uptake of nutrients by the plant and evade serious diseases.

    Other options:-

    • Other than rapid rooters, there are other hydroponic options you can go for like, rock wool, coconut fibre, peat and oasis cube.
    • While the rapid rooters retain a lot of water, oasis and coir retain very little water.
    • The rock wool has a high PH concentration; therefore, the cubes should be rinsed in the solution of both water and vinegar to neutralize the PH before putting the seeds in the cubes to grow.
    • Mix a teaspoon of vinegar in a cup half-filled with water and dip the cubes into the resulting solution shaking off the excess.
    • Rock wool needs more attention because it is alkaline in nature.

    Location: -

    • The container should be placed where it can receive maximum light.
    • If you choose to grow your seeds in the house, the convenient places are like on a table or near a window where there is partial light either in the morning or in the afternoon.
    • In case you want to grow outside, then you should select a partially sunny location like a porch.
    • The container should be away from heavy rainfall and winds.
    • Since the container is small and portable, it should be moved from one place to another to protect it from bad weather.

    Maintenance: -

    • Water should be added only when the cubes start to get dry. Because much water favours the development of molds on the rock wool.
    • On the other hand, if there is no water for a long time the seeds will not germinate. Thus, the cubes should be moist but not wet or dry.
    • When the seedlings reach 2 inches in height, add diluted nutrient solution or fish water to the water in the container. This will greatly boost the root growth.

    Transplanting: -

    • The seedlings are ready for transplanting to a hydroponics grow system when they reach 3-4 inches in height. Look for 3 to 4 true leaves.
    • Fill the net pot with clay pellets until it is half full. Which supports the plants.
    • The best time of day to plant is in the late afternoon when the sun is not hot, and the wind has calmed down. By taking advantage of this time of day, the new plants have overnight to acclimate.
    • Strong sun and wind are very hard on new transplants. Unless watered carefully, and in some cases provided with some shelter from the wind and sun, they can severely wilt.
    • This places the plants under stress at the very beginning of their growing cycle and is not a good idea because sometimes they never bounce back and don't thrive as well as they could have.
  • Growing Peppers in Aquaponics

    Growing peppers in aquaponic units: There are many varieties of peppers, all varying in colour and degree of spice, yet from the sweet bell pepper to the hot chili peppers (jalapeno or cayenne peppers) they can all be grown with aquaponics. Peppers are more suited to the media bed method but they might also grow in 11 cm diameter NFT pipes if given extra physical support.

    Growing conditions: Peppers are a summer fruiting vegetable that prefers warm conditions and full sun exposure. Seed germination temperatures are high: 22 - 34 °C. Seeds will not germinate well in temperatures < 15 °C. Daytime temperatures of 22 - 28 °C and night-time temperatures of 14 -16 °C favour best fruiting conditions under a relative humidity of 65 - 60 percent. Optimal temperatures at root level are 15 - 20 °C. In general, air temperatures below 10 - 12 °C stop plant growth and cause abnormal deformation of the fruits, making them unmarketable. Temperatures > 30 - 35 °C lead to floral abortion or fallout. In general, spicier peppers can be obtained at higher temperatures. The top leaves of the plant protect the fruit hanging below from sun exposure. As with other fruiting plants, nitrate supports the initial vegetative growth (optimum range: 20 - 120 mg/litre) but higher concentrations of potassium and phosphorus are needed for flowering and fruiting.

    Growing instructions: Transplant seedlings with 6 - 8 true leaves to the unit as soon as night temperatures settle above 10 °C. Support bushy, heavy-yielding plants with stakes or vertical strings hanging from iron wires pulled horizontally above the units. For red sweet peppers, leave the green fruits on the plants until they ripen and turn red. Pick the first few flowers that appear on the plant in order to encourage further plant growth. Reduce the number of flowers in the event of excessive fruit setting to favour the growing fruits to reach an adequate size.

    Harvesting: Begin harvesting when peppers reach a marketable size. Leave peppers on the plants until they ripen fully by changing colour and improve their levels of vitamin C. Harvest continually through the season to favour blossoming, fruit setting and growth. Peppers can be easily stored fresh for 10 days at 10 °C with 90 - 95 per cent humidity or they can be dehydrated for long-term storage.

    pH: 5.5 - 6.5

    Plant spacing: 30 - 60 cm (3 - 4 plants/m2, or more for small-sized plant varieties)

    Germination time and temperature: 8 - 12 days; 22 - 30 °C (seeds will not germinate below 13 °C)

    Growth time: 60 - 95 days

    Temperature: 14 - 16 °C night time, 22 - 30 °C daytime

    Light exposure: full sun

    Plant height and width: 30 - 90 cm; 30 - 80 cm

    Recommended aquaponics method: media beds

    Reference: http://www.fao.org/3/a-i4021e.pdf

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