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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: -

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: -

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.

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’s 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 wastewater 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 neighbourhood 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

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 particle’s changes to steam, expanding the particles too small, spongelike 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.

 

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 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 micronutrients 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.

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 retranslated 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 monopotassium 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.

 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.

 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.

• 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 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 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

Cherry Tomato: - 

Tomatoes are an excellent summer fruiting vegetable to grow using all available methods although physical support is necessary.

A higher nitrogen concentration is preferable during the early stage to flower stage. However, potassium should be present from the flowering stage to fruit setting to growth.

Tomatoes are rich in vitamins A and C, low in calories and a source of lycopene (the “Red” in tomatoes), which has been tapped as a cancer-fighting agent.

If you have experience in growing tomato you know that to get the high-quality products and good yields with a limited space can be quite a challenge.

We’ll try to consolidate all important things that you need to know if you want to grow tomatoes, have high-quality products and great yields in your greenhouse. We’ll also share our experience and you’ll see great benefits of aquaponic systems for profitable commercial tomato production.

Tomato is one of the most demanded vegetables. In the season but also out of the season. It is used as a fresh produce but also an input for the production of many different products like sauces. One of the greatest advantages is that it grows in the air and we can use a lot of greenhouse height for our production.

The main advantages of growing tomatoes in protected spaces (greenhouses) compared to other crops are:

• It is highly attractive and demanded product
• We can have very high yields per sqm
• There are many hybrids that are resistant to diseases.

Growing Conditions: -

• When you have set up your aquaponic system and decided to grow tomato you need to pay attention to some details. If you make mistakes, in the beginning, you will not see problems usually until it’s too late to fix them.

1. Type of aquaponic system?
2. How to band tomatoes for the best vertical growth?
3. How to make tomato grow faster?

• Each and every part of the aquaponic system that is not synched to specific natural laws can create problems in the future. These problems can be insignificant but sometimes these problems can lead to total disaster. For that reason, it is important to have all the information and to understand each part of the system.
• The first and most important factor is to choose the right aquaponic system for tomato production.
• Out of all aquaponic systems, BED system is probably the most convenient for many types of crops. But it is not a profitable system. Because it is quite robust, it takes a lot of space and is quite expensive to construct.
• For profitable tomato cultivation, one of the best aquaponic systems is DUTCH BUCKET

• In Dutch bucket aquaponic system we are using a number of buckets for growing our crops in them. In buckets, we put any growing media that is suitable for aquaponics. When we are irrigating crops the water is moving through growing medium and feeding the root of our plants.
• We need to make sure that there is always some water in the bottom of the bucket.
• We can achieve this by drilling drainage holes on a certain height of the bucket. For this system to work we do not need any additional siphons.
• When constructing Dutch bucket aquaponic system pay special attention to the following

1. Greenhouse space usage
2. Pipes and nozzle clogging
3. Space for roots development
4. Bucket drainage

• Tomatoes prefer warm temperatures with full sun exposure. Below 8-10°C, the plants stop growing, and night temperature 13-14 encourage fruit set. Temperature above 40°C cause floral abortion and poor fruit setting.
• Tomatoes have a moderate tolerance to salinity, which makes them suitable for areas where pure freshwater is available. However, higher salinity at fruiting stage improves quality of the products.

Planting Instructions: -

• Set stakes or plant support structures before transplanting to prevent root damage.
• Transplant the seedlings into units 3-6 weeks after germination when the seedling is 10-15 cm and when the night time temperatures are constantly above 10°C.
• In transplanting the seedlings, avoid waterlogged conditions around the plant collar to reduce any risk of diseases.
• Once the tomato plants are about 60 cm tall, start pruning the unnecessary upper branches. Remove the leaves from the bottom to 30cm of the main stem for better air circulation and reduce fungal incidence.
• Remove the leaves covering each of the fruiting branches soon before ripening to favour nutrition flow to the fruits and to accelerate maturation.

Harvesting: -

• Most cherry tomato plants will start flowering in about a month. Flowers will be followed by tiny green fruits. After a few weeks, those turn into full-blown cherry tomatoes you can harvest.
• A truly ripe cherry tomato will come off its stem very easily and is well worth waiting an extra day for, so hold off on picking them until they're ripe. Then, pluck individual fruits every day for best results. With luck, your plant will continue to produce right up until winter. If the weather turns unseasonably cool or an early frost threatens, you can tuck an old sheet over and around the plant to extend your harvest season.
• Fruits can be easily maintained for 2-4 weeks at 5-7°C under 85-90 percentage relative humidity.

Tips: -

• PH: 5.5-6.5
• Plant spacing: 40-60cm (3-5 plants/sqm)
• Germination time and temperature: 4-6 days and 20-30 °C
• Growth time: 50-70 days till the first harvest; fruiting 90-129 days up to 8-10 months.
• Optimal temperature: 13-16°C night, 22-26 °C day
• Light exposure: full sun
• Recommended methods: Media Beds and DWC

• Growing hydroponics lettuce is one of the easiest and the best ways to start hydroponic gardening.
• Lettuce is a simple to grow all round plant that can ensure you get great results when grown in soil, as long as you keep pests off it.
• This is where growing lettuce hydroponically will make perfect sense and will be a terrific first task for any hydroponic setup.
• Lettuce hydroponics will typically look after themselves and do not need a lot of nutrients as other heavy feeding plants like tomatoes.
• It’s obviously still a great practice to check out your growing hydroponic lettuce plants every day for pests or other problems, though these problems are considerably decreased with hydroponics, particularly indoor hydroponics.
• Actually, the only issue you could come across when growing hydroponic lettuce at home is size.
• Lettuce is in high demand and has a high value in urban and peri-urban zones, which makes it a very suitable crop for large-scale commercial production.

Note: -

• Check lettuce for signs of downy mildew, powdery mildew or gray mold and get rid of any infected plants.
• Water that’s heavily chlorinated can lead to issues with lettuce. You should use lightly chlorinated city water or well water.

Lettuce varieties: -

Lettuce can be characterized based on their leaf and head formation.

Crisp head or iceberg: -

• Crisp head lettuce, more commonly known as iceberg, has a tight head of crisp leaves. Often found in the local salad bar, it is actually one of the most difficult lettuce varieties to grow. This lettuce variety is not fond of hot summer temperature or water stress and may rot from the inside.
• Start iceberg lettuce via seed directly sown 18-24 inches apart or started indoors and then thinned 12-14 inches between heads. Some iceberg lettuce varieties include Ballade, Crispino, Ithaca, Legacy, Mission, Salinas, Summertime and Sun Devil, all of which mature in 70-80 days.

Romaine or Cos: -

• Romaine varieties are typically 8-10 inches tall and upright growing with spoon-shaped, tightly folded leaves and thick ribs. Colouration is medium green on the exterior to a greenish white inside with the outer leaves.
• Sometimes being tough whilst the interior foliage is tender with wonderful crunch and sweetness. Different types of this lettuce are Brown Golding, Chaos Mix black, chaos Mix white, Devil’s Tongue, Dark green Romaine, De Morges Braun, Hyper Red Rumple, Little Leprechaun. All of which mature within around 70 days.

Butterhead, Boston or Bibb: -

• One of the more delicate varieties of lettuce, Butterhead is creamy to light green on the inside and loose, soft and ruffled green on the exterior. These different types of lettuce may be harvested by removing the entire head or just the outside leaves and easier to grow than crispheads, being more tolerant of conditions.
• Less likely to bolt and rarely bitter, the butterhead lettuce varieties mature in about 55-75 days and spaced similarly to the crispheads. These varieties of lettuce include Blushed Butter Oak, Buttercrunch, Carmona, Divina, and Yugoslavian red.

Growing Conditions: -

• Lettuce is a winter crop. For head growth, the night air temperature should be 3-12°C, with a day temperature of 17-28°C.
• The generative growth is affected by photoperiod and temperature extended daylight warm conditions(>18°C) at night cause bolting. Water temperature >26°C may also result in bolting and leaf bitterness.
• The plant has low nutrient demand; however higher calcium concentrations in water help to prevent tip burn in leaf in summer crops.
• The ideal PH is 5.8-6.2. but lettuce still grows well with a PH as high as 7, although some iron deficiencies might appear owing to reduced bio-availability of this nutrient above neutrality.

Growing instructions:

• Seedlings can be transplanted in units at three weeks when plants have at least 2-3 true leaves. Supplemental fertilization with phosphorous to the seedlings in the second and third weeks favours root growth and avoids plant stress at transplant.
• Take care not to damage the roots of plants during transplanting because such damage will make the plant susceptible to disease infection.
• It is advisable to transplant the plant in the late afternoon to prevent them becoming stressed in the heat of the day under high UV conditions.
• The transplant will begin to adapt to the new location at night and roots will start to grow into the solution below.
• Make sure the plants base is touching the flow of nutrient solution below when transplanting.
• To achieve crisp sweet lettuce, grow plants at a fast pace by maintaining high nitrate levels in the unit. When air and water temperatures increase during the season, use bolt -resistant(summer) varieties. If growing in media beds, plant new lettuces where they will be partially shaded by taller nearby plants.

Lighting: -                                      

• Lettuce grows up vigorously with fluorescent lighting. It would obviously grow far better with the more expensive lighting specially created for hydroponics, like HID and some of the latest LED grow lights for indoor plants.
• However, regarding cost-effectiveness, from the viewpoint of the small-scale grower, fluorescent lighting is the best.
• These are cool weather crops, so too much heat can, in fact, delay germination.

Harvesting Hydroponics lettuce: -

Hydroponics harvesting depends on the following factors

• First, this will depend on what type you are growing. Romaine takes up to 85 days. Bibb and Loose-leaf lettuce can take 45 to 55 days.
• It has to do preference, growing lettuce indoors then you have to manage the environment and prolong your harvest.
• The majority of hydroponic lettuce production systems created around two ideas, either the floating raft system or the nutrient flow technique (NFT) system.
• The floating raft method is of particular interest since it is very affordable and can produce a lot of hydroponic lettuce.
• One of the major issues with raft systems is that the hydroponic lettuce nutrients solution is continually stagnant and will require that you use pumps to circulate water and produce important aeration.
• If the roots are not getting the precious oxygen, floating raft systems experience substantial loses of crops in the form of nutrients.

Below are some types that work well in hydroponics and with indoor artificial lighting:

• Royal Oakleaf is a darker green variety of lettuce that does extremely well in hydroponic growing systems and is also resistant to heat.
• Tango grows perfectly in cooler environmental only.
• Red Fire is a deep red, loose leaf variety that’s ideal for both warm and cool climates.
• Green Ice is a variety of green loose that offers a long picking season.

Hydroponic romaine lettuce also does well though it usually takes a little bit longer to attain maturity.

Tips: -

• When you harvest lettuce with the roots attached, it will prolong storage life by two to four weeks.
• To prevent getting water mold such as Pythium or Phytophthora in your hydroponic lettuce system, use bleach to sanitize the tray between plants. If the lettuce gets infected, the plant is a loss.