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Hydroponics Cultivation of Crops
Dinkar J. Gaikwad* and Sagar Maitra
Center for smart agriculture, Centurion University of Technology and Management, Paralakhemundi,
Odisha- 761211
*Corresponding author: gaikwad@cutm.ac.in
Abstract
Hydroponics technology is possibly the most intensive and a versatile method of growing
crops production at present as it allows optimum utilization of nutrient solution, water
and space, as well as a better control of climate and plant protection factors. Hydroponic
technology can be an efcient mean for food production from extreme environmental
ecosystems such as deserts, mountainous regions, or arctic communities. Furthermore,
hydroponics production increases the quality of crops and its productivity, which results in
higher competitiveness and economic income. Several types of hydroponics systems can
be used to grow the crops. Commercially Nutrient Film Technique (NFT) has been used
across a globe for successful production of the leafy as well as other exotic vegetables
cultivation. Hydroponic systems use mineral nutrient solutions to feed the plants in
water of using several non-soil growing media. Despite of having few disadvantages,
Hydroponics technology provides variety of benets when compared with conventional
farming methods.
Keywords: Hydroponics, growing media, structures, nutrient solution
1. Introducon
The word hydroponics was derived from combination of two greek words, hydro,
meaning water, and ponos, meaning labor (i.e., working water). It may be dened as the
technique of growing of plants in nutrient-rich solutions instead of soil. Hydroponics
is used in the commercial production of many greenhouses crops. Hydroponics is
the fastest growing sector of agriculture, and it could very well dominate sustainable
food production in the future. As global population increasing rapidly and arable land
declines due to urbanization, people will turn to new technologies like hydroponics or
soilless farming. This soilless growing technique uses nutrient solutions to feed plants
31
Chapter
Hydroponics Cultivation of Crops. In: Protected Cultivation and Smart Agriculture edited by Sagar
Maitra, Dinkar J Gaikwad and Tanmoy Shankar © New Delhi Publishers, New Delhi: 2020, (pp. 279-
287). ISBN: 978-81-948993-2-7, D OI: 10.30954/NDP-PCSA.2020.31
280 Protected Cultivation and Smart Agriculture
in water in absence of soil. Hydroponics has the potential to sustain a large proportion
of the world’s population and to allow third world countries to feed their own people,
even in places where soil is less fertile and water is limited. The technology can also
be used as a valuable source of food production in places where space is scarce. In
hydroponics, Non soil growing media can be used to provide mechanical support
to the roots which support to the plants weight and hold it upright. Sand, gravel,
river rock, oasis cubes, oral foam, vermiculite, rockwool, perlite, peat moss, coir,
coco-peat and sawdust is commonly used media in hydroponics (Fig. 1). An essential
element has a clear physiological role and its absence prevents the complete plant
life cycle (Taiz and Zeiger 1998). Currently, 17 elements are considered essential for
most plants, these are carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium,
calcium, magnesium, sulphur, iron, copper, zinc, manganese, molybdenum, boron,
chlorine and nickel (Salisbury and Ross 1994). These all 17 essential elements are
supplied based on different dilutions of the media described by Hoagland and Arnon
(1938).
Fig. 1: Hydroponic system with roots immersed in nutrient solution and air bubbles
2.1. Advantages
Crops can be grown where no suitable soil exists or where the soil is
contaminated with disease.
Labor for tilling, cultivating, fumigating, watering, and other traditional
practices is largely eliminated.
Maximum yields are possible, making the system economically feasible in
high-density and expensive land areas.
Conservation of water and nutrients is a feature of all systems. This can lead to
a reduction in pollution of land and streams because valuable chemicals need
not be lost.
Soil-borne plant diseases are more readily eradicated in closed systems, which
can be totally ooded with an eradicant.
Hydroponics Cultivation of Crops 281
More complete control of the environment is generally a feature of the system
(i.e. root environment, timely nutrient feeding, or irrigation), and in greenhouse-
type operations, the light, temperature, humidity, and composition of the air can
be manipulated.
Water carrying high soluble salts may be used if done with extreme care. If
the soluble salt concentrations in the water supply are over 500 ppm, an open
system of hydroponics may be used if care is given to frequent leaching of the
growing medium to reduce the salt accumulations.
2.2. Disadvantages
The original construction cost per acre is great.
Trained personnel must direct the growing operation. Knowledge of how plants
grow and of the principles of nutrition is important.
Introduced soil-borne diseases and nematodes may be spread quickly to all beds
on the same nutrient tank of a closed system.
Most available plant varieties adapted to controlled growing conditions will
require research and development.
The reaction of the plant to good or poor nutrition is unbelievably fast. The
grower must observe the plants every day.
3. Hydroponic Structures
There are many different systems for hydroponic cultivation which are designed to
maximise yield. They differ mainly in function and complexity.
3.1. Drip systems: Drip systems are reasonably simple to control moisture in.
Nutrient solution from the tank or reservoir is provided to individual plant roots in
appropriate proportion with the help of pump (Rouphael and Colla, 2005). Plants are
usually placed in moderately absorbent growing medium so that the nutrient solution
drips slowly.
3.2. Wick System: This is simplest, least used type of hydroponic system requiring
no electricity, pump and aerators (Shrestha and Dunn, 2013). Water or nutrient
solution supplied to plants through capillary action. You can control the amount of
water getting to the plant by using a larger/wider wick, or more than one. This system
works well for small plants, herbs and spice and doesn’t work effectively that needs
lot of water.
3.3. Deep water culture system: The deep water culture system is the easiest system
to use. A Styrofoam or similar kind of oating platform on the nutrient solution holds
the plants. External supply of oxygen is provided to the roots of the plants through a
aquarium air pumps. Water culture is the system most often used for leafy vegetables
(Fig. 2).
282 Protected Cultivation and Smart Agriculture
Fig. 2: Mesh-pots lled with fenugreek plants placed into a Styrofoam sheet oated on
trays having nutrient solution
3.4. NFT systems: NFT was developed in the mid 1960’s in England by Dr. Alen
Cooper, whereby a very shallow stream of water containing all the dissolved nutrients
required for plant growth is re circulated past the bare roots of plants in a water tight
thick root mat, which develops in the bottom of the channel. NFT is widely suitable
to grow various vegetables.
Fig. 3: Growth of spinach in A-Frame hydroponics structure
Hydroponics Cultivation of Crops 283
3.5. Ebb-Flow (ood and drain) systems: Flood and drain systems can vary quite a
bit in design and supposed to be rst commercial hydroponic system which works on
the principle of ood and drain. Nutrient solution from reservoir swamped through
a water pump into system. The system uses gravity to return the excess water to the
reservoir to be reused.
3.6. Aeroponic systems: The aeroponic system is probably the most high-tech type of
hydroponic gardening. In this technique, plants are grown with their roots suspended
in air while being sprayed continuously with a nutrient solution. The misting’s are
usually done every few minutes. The aeroponic system needs a short cycle timer
unlike other systems that runs the pump for a few seconds every couple of minutes.
4. Growing Mediums in hydroponics
In most hydroponic systems, growers use different types of hydroponic media to help
support their roots and maintain a good water/oxygen ratio.
4.1. Rockwool
Rockwool is one of the most common growing media’s used in hydroponics.
Rockwool is a sterile, porous, non degradable medium that is composed primarily
of granite and/or limestone which is super heated and melted, then spun into a small
threads like cotton candy. The rockwool is then formed into blocks, sheets, cubes,
slabs, or ocking. Rockwool sucks up water easily so you’ll want to be careful not to
let it become saturated, or it could suffocate your plants roots, as well as lead to stem
rot and root rot. Rockwool should be pH balanced before use. That’s done by soaking
it in pH balanced water before use.
4.2. Coco coir
Coco coir /Coconut ber is from the outer husk of coconuts. What was once
considered a waste product, is one of the best growing mediums available. Although
coco coir is an organic plant material, it breaks down and decomposes very slowly,
so it won’t provide any nutrients to the plants growing in it, making it perfect for
hydroponics. Coco coir is also pH neutral, holds moisture very well, yet still allows
for good aeration for the roots. Coco ber comes in two forms, coco coir (ber), and
coco chips. Their both made of coconut husks, the only difference is the particle size.
The coco ber particle size is about the same as potting soil, while the coco chips
particle size is more like small wood chips.
4.3. Perlite
Perlite is mainly composed of minerals that are subjected to very high heat, which
then expand it like popcorn so it becomes very light weight, porous and absorbent.
Perlite has a neutral pH, excellent wicking action, and is very porous. Perlite can
by used by itself, or mixed with other types of growing media’s. However because
284 Protected Cultivation and Smart Agriculture
perlite is so light that it oats, depending on how you designed your hydroponic
system, perlite by itself may not be the best choice of growing media for ood and
drain systems. Perlite is widely used in potting soils, and any nursery should carry
bags of it.
4.4. Vermiculite
Vermiculite is a silicate mineral that like perlite, expands when exposed to very high
heat. As a growing media, vermiculite is quite similar to perlite except that it has a
relatively high cation-exchange capacity, meaning it can hold nutrients for later use.
Also like the perlite, vermiculite is very light and tends to oat.
4.5. Oasis Cubes
Oasis Cubes are similar to Rockwool cubes, and have similar property’s. But oasis
cubes are more like the rigid green or white oral foam used by forests to hold the
stems in their ower displays. Oasis cubes are an open cell material which means
that the cells can absorb water and air. While oasis cubes are similar to rockwool,
Oasis cubes don’t become waterlogged as easily as rockwool cubes. Even so don’t
let it stay in constant contact with the water supply, or you’ll still have water logging
issues.
4.6. Sand
Sand Is actually a very common growing media used in hydroponics. Sand is like
rock, just smaller in size. Because the particle size is smaller than regular rock,
moisture doesn’t drain out as fast. Sand is also commonly mixed with Vermiculite,
Perlite, and or coco coir. All help retain moisture as well as help aerate the mix for
the roots.
4.7. Rice Hulls
Depending on the availability, rice-hulls may be used. It’s a by-product of the rice
industry. Even though they are an organic plant material, they break down very slowly
like coco coir, making them suitable as a growing media for hydroponics. Rice hulls
are referred to as either fresh, aged, composted and parboiled, or carbonized. Fresh
rice hulls are typically avoided as a hydroponic growing media because of the high
probability of contaminants such as rice, fungal spores, bacteria, decaying bugs, and
weed seeds. Parboiled rice hulls (PRH) is done by stemming and drying the rice hulls
after the rice has been milled from them. This kills any spores, bacteria, and micro-
organisms, leaving a sterile and clean product.
5. Importance of pH in Hydroponics
pH (hydrogen ion concentration) is a numeric scale used to specify the acidity or
basicity of an aqueous solution. pH is very important in hydroponics and organic as
well as regular soil gardening. pH is measured on the scale of 1 to 14 with 7 being
Hydroponics Cultivation of Crops 285
neutral. pH of the nutrient solution plays important role in hydroponics cultivation.
When the pH is not at the proper level the plants will lose its ability to absorb some of
essential elements required for healthy growth. For all plants there is a particular pH
level that will produce optimum results. This pH level will vary from plant to plant,
but in general most plants prefer a slightly acidic growing environment between 5.5
to 6.5 (Trejo-Tellez and Gomez, 2012). Use the nutrients they must be dissolved in
the solution. once the nutrients have precipitated out of the solution your plant can
no longer absorb them and will suffer deciency and death if left uncorrected. Some
nutrient will precipitate out of the solution when the pH drops also.
Fig. 4: pH chart for hydroponics system
6. Total Dissolved Solids (TDS) or Electrical Conducvity (EC) in Hydroponics
Conductivity/TDS is really a measure of the nutrients in the solution. The higher
the conductivity, higher dissolved solids there are in the solution. Low conductivity
implies a low nutrient concentration, which usually results in nutritional deciencies
and slow growth rates of plants. However, very high level can burn and or kill the
plants. Delicate plants cuttings and seedlings can experience burning if conductivity/
TDS is too high. Once the plant begins growing, they need strong nutrient solution so
conductivity can be increased by adding concentrated nutrients. Some plant prefers a
milder nutrient strength while other plants produces better quality fruits with a higher
concentration.
286 Protected Cultivation and Smart Agriculture
7. Nutrient Soluon
For proper growth, plants must be supplied with combination of macro and micro
nutrients i.e. nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron,
manganese, boron, zinc, copper, molybdenum, and chlorine (Fig. 5). Within certain
limits of composition and total concentrations, there can be a rather wide range in the
nutrient solutions suitable for plant growth. Usually the small amount of minerals in
the water supply can be ignored. When nutrients are decient or present in excess in
the solution, however, the plants will suffer.
Fig. 5: Lettuce cultivated in hydroponics
For this reason, you must be careful in selecting and adding the minerals that go
into the nutrient solution. Purity of the nutrient materials or chemicals is important
in preparing a solution. In some cases, the fertilizer grade of a chemical may be
used, and in other cases, a technical-grade or food-grade chemical may be needed.
The best grades have few impurities; the lower or fertilizer grades may have more.
Sometimes the plants may use the impurities. Because of the low price of the
fertilizer-grade chemicals, they should be used whenever possible. Many formulas
have been devised for supplying the nutrient requirements for plant growth. Most
of these recommendations will give satisfactory results, but they often require less
than one gram of chemicals that are not easy to obtain. Evaporation of the solution,
whether through the atmosphere or through plants, reduces the amount of water and
increases the proportion of salt in the solution. Too much salt may be detrimental to
the plants.
Hydroponics Cultivation of Crops 287
Table 1: Composition of Modied nutrient solution
Compounds Concentration of stock
solution (mM)
Vol. of stock solution per
litre of nal solution (ml)
Macronutrients
KNO31000 6
Ca (NO3)2. 4H2O 1000 4
KH2PO41000 2
MgSO4. 7H2O 1000 1
Micronutrients
KCL 25
2
H3BO312.5
MnSO4. H2O 1.0
ZnSO4. 7H2O 1.0
CuSO4. 5H2O 0.25
MoO30.25
Fe Na EDTA 64 1
8. Conclusion
Hydroponic culture is possibly the most intensive method of crop production in today’s
agricultural industry mainly used in developed and underdeveloped countries for
food production in limited space. It is highly productive, conservative of water, land
and space, and protective of the environment. The fame of hydroponics has increased
dramatically in a short period of time leading to an increase in experimentation
and research in the area of indoor and outdoor hydroponic gardening. In India, the
hydroponic industry is expected to grow exponentially in the near future.
References
[1] Hoagland, D.R. and Arnon, D.I. 1938. The water culture method for growing plants
without soil. California Agricultural Experiment Station Circulars, 347: 1-39.
[2] Rouphael, Y. and Colla, G. 2005. Growth, yield, fruit quality and nutrient uptake of
hydroponically cultivated zucchini squash as affected by irrigation systems and growing
seasons. Sci. Hort., 105: 177-195.
[3] Salisbury, F.B. and Ross, C.W. 1994. Plant Physiology. Wadsworth Publishing Company,
ISBN 0-534-15162-0, California, U. S. A.
[4] Shrestha, A. and Dunn, B. 2013. Hydroponics. Oklahoma Cooperative Extension Services
HLA-6442.
[5] Taiz, L. and Zeiger, E. 1998. Plant Physiology. Sinauer Associates, Inc. Publishers.
Sunderland, ISBN : 0878938311, Massachusetts, USA.
[6] Trejo-Tellez, L.I. and Gomez, M.F.C. 2012. Nutrient Solutions for Hydroponics Systems,
Hydroponics – A Standard Methodology for Plant Biological Researches, Dr. Toshiki
Asao (eds). ISBN 978-953-51-0386-8.
