A Comparative Analysis of Two Plant Growth Mediums: Hydroponic vs. Soil
Table Of Contents
Project Abstract
<p> <b>ABSTARCT </b></p><p>Plants do not need soil in order to grow and survive. Soil act as a medium for plant to
help support it and to retain nutrients. However, any medium that is stable enough to support
plant and can retain nutrients can do the same job as soil without being restricted to the ground.
This is where hydroponics comes in; hydroponic is a method of growing plants using mineral
solution, in water, without soil. This method can be extremely helpful to countries that have poor
land, which is not able to sustain agriculture. The purpose of this lab is to prove that hydroponic
horticulture can be just as effective if not better than plants traditionally grown in soil. The
hypothesis goes like this if the hydroponic plants and plants grown in soil are given the same
germinating and growing conditions, then the hydroponic plants will do as well if not even better
than the plants grown in soil. This experience was conducted using an assortment of fruit,
vegetables and herbs. Half the seeds where grown hydroponically, while the other half was
grown in soil; both were kept in the same conditions, in order to not alter the experiment in favor
of one or the other. The plants were grown for thirty days, in order to ensure accurate results.
After a month the stated hypothesis was proven correct, the hydroponic and soil plants grew
almost the same, with the hydroponic plants germinating faster and growing faster than the soil
plants
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Project Overview
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<b>INTRODUCTION </b></p><p>Often time when learning about plants, we stumble unto the basic so called necessities of
plants, the big four as some call it, sun, soil, oxygen and water. Three out of the four basic
necessities given are true. Plants are autotrophs that make their own food using the sun using a
process called photosynthesis. The word photosynthesis means to put together with light and this
is exactly what occurs. It occurs in the chloroplasts of plants. This process is limited to the
supply of light, water and carbon dioxide. Limiting any one of the factors on the left can greatly
impact the amount of photosynthesis produced. During the process of photosynthesis electrons
are boosted up by the energy from the sunlight. The chloroplast uses these electrons, along with
the carbon dioxide and hydrogen ions, to produce sugar molecules (Campbell et al., 2009). The
reaction steps add up to the following photosynthetic equation:
Photosynthesis occurs in two stages, the light dependent reaction and the Calvin cycle, both with
their own individual steps. In the light reaction the energy in sunlight is converted to chemical
energy. The reaction relies on molecules built in the membranes of thylakoids. First, light energy
is captured by the chlorophyll molecules in membranes. Then the captured energy is used by the
thylakoid to remove electrons from water. This divides the water into oxygen and hydrogen ions.
This are considered waste products and are used to make NADPH. The captured energy is also
used to generate ATP. The Calvin cycle makes sugar from the atoms in carbon dioxide including
Running Head the hydrogen ions and electrons carried in NADPH. The ATP made in the light reaction provides
the energy needed to make to sugar. The Calvin cycle is known as the “light independent
reaction” because it does not need light to begin. However, it does need ATP and NADPH which
comes from the light cycle (Williamson et al. 2009). It is obvious to see that the sun or light is an
important contributor to plant growth and development. </p><p>
The fact that plants need oxygen is unarguable. This is because all cells not just plant
cells need oxygen to perform aerobic respiration. Respiration is the process of breaking down
food to get energy. The cells in the green part of plants where photosynthesis is occurring get the
oxygen they need from the oxygen produced by photosynthesis. This means that the cells in the
leaves and stems of the plants are getting adequate requirements. The problem comes from the
cells in the roots of the plants, where there is no photosynthesis occurring due to the lack of light.
In the majority of plants this cells get their oxygen from air in the spaces between the dirt
particles in the soil. “All living things combine food with oxygen to attain energy. Plants are no
exception. They make food and combine it with oxygen in order to release energy for
themselves. On the contrary, during day time, plants release lots of oxygen in the air because
while making food during photosynthesis, they change carbon dioxide and water into food and
oxygen. But, at the night time, just like other living beings, plants absorb oxygen to breath”
(Insaan, n.d.). If the plants have no access to oxygen there would not be any respiration and the
plant would not be able to function. Due to the lack of oxygen the roots will not be able to grow
to take in water, which would cut off the nutrients needed for the plants to grow and survive.
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Plants need water to grow. One of the major factors driving water movement in plants is
transpiration. Transpiration is the loss of water from plants in the form of vapor (evaporation).
Plants use 95% of the water absorbed from soil for transpiration, 5% is used during
photosynthesis for the production of carbohydrates necessary for plant growth (Whiting et al,.).
The growth of plants is dramatically affected by the amount and timing of water applied during
its production. Different stages of plant growth are more sensitive to water stress than others.
The ability of plants to resist stress from insects and/or disease is influenced by water. If plants
do not have water, they would die, because they are missing one of the main components needed
to ensure the efficacy of their growth.
While researching the necessities for plant growth, there was no suitable reason given for
why plants need soil to grow. The reason for this is because they do not. The purpose of plants is
to anchor plant roots and act as a source of water and nutrients needed for healthy growth.
However, couldn’t any medium capable of retaining water and nutrients do the same job as soil?
Technically speaking soil is just a glorified medium, and any substance with high absorbency
materials could do the same job.
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Hydroponic is a method of growing plants using mineral solution, in water, without soil.
In the 18th century researchers discovered that plans absorb essential nutrients as inorganic ions
in water. The soil acts as a mineral nutrient reservoir but the soil is not essential to the plant
growth. When the mineral nutrients in soil are dissolved, plant roots are capable of absorbing
them. When the mineral nutrients are artificially introduced into a plants water supply soil is no
longer needed for the plant to become successful. This are not just for some plants, almost all
terrestrial plants will grow with hydroponics. This is the key. Hydroponics allows the grower
several advantages compared to soil. It allows the grower to control the nutrition levels in the
reservoir which allows for lower nutrition requirements, the water remains in the system and can
be reused, which lower the amount the water required. There is no nutrition pollution being
released in the environment because it is in a controlled system. It allows for stable to high
yields, diseases and pest are easier to get rid of than in soil because the system can be mobile, it
is easy to harvest and there is no pesticides damage. The most important advantage of
hydroponics is that it uses less water than soil and that it can be used in places where in-ground
agriculture or gardening are not possible.
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This is extremely relevant when applied to current global conditions. 71% of the Earth is
made up from water but only 3% is freshwater needed for human use. Places in some parts of the
Middle East are dry, desolate places lacking any vegetation because the land is not suitable for
agriculture, due to the lack of rainfall and human activities. Hydroponics can help produce crops
suitable for human consumption and already have. Countries such as Israel have implemented
hydroponic techniques with great success. NASA has been trying to develop hydroponic system
that can be used in space. This will allow fresh plants to be grown in space stations. Hydroponics
is the perfect solution because it uses less water than soil grown plant and it can be grown
virtually everywhere. Regions with poor soil conditions will no longer be dependent on exports
from other countries. Not only will hydroponics help reduce the amount of water wasted per year
due to poor irrigation of the soil, but it provides a solution to those country who struggle because
of the inability to produce their own crops.
It is not that hard to see that plants do perfectly fine without soil and in fact can thrive
without it. Plants need oxygen, nutrients, water and sun. The purpose of this lab is to prove that
hydroponic horticulture can be just as effective if not better than plants traditionally grown in
soil. The hypothesis goes like this if the hydroponic plants and plants grown in soil are given the
same germinating and growing conditions, then the hydroponic plants will do as well if not even
better than the plants grown in soil.
<br></p><p><b>METHODS AND MATERIALS </b></p><p>This experiment could easily be replicated by anyone looking to test and compare plants
grown hydroponically and those that are grown in soil. In order to replicate this experiment the
person would need to gather the material needed (Al 1) and carefully follow the procedures
indicated below. The person would need seeds from varying plants fruits, vegetables and herbs.
For this large experiment the seeds used were brand name spinach and generic spinach seeds,
basil, watermelon, lettuce, parley, habanero peppers, French onions, carrot and kale. To duplicate
this experiment on a smaller scale a person would need kale or spinach, watermelon, and parsley
or basil. This is because the seeds stated germinate quickly to expedite the experiment. The
varying seeds would give us an accurate result of the hydroponics and soil plants efficacy among
different vegetation. Six used ice cream containers were used as containers for the hydroponics.
They were covered in black plastic bags so as to not let the sunlight penetrate through them,
because this will cause algae to grow inside the reservoir affectively ruining the experiment and
not allowing the hydroponics to grow. Five holes, each one and half inch in diameter were
carved into the lids. </p><p>
The holes cut into the lids were slightly smaller than the net pots, so that they do not fall through.
Net pots are containers like items, used to hold the hydroponics inside of them. They keep the
plants supported on the lids; when considering purchasing them, make sure that the lips of the
net pots are larger than the net pots itself, this allows the net pots to have a “grip” when
supporting the hydroponics, and they look something like this depending on the company selling
them:
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Rockwool cubes are the growing medium that the seeds would be planted in, they will act
as a substitute for soil. They are made out of Basaltic rock that is melted down and through a
manmade process is spun into small fibers, a process similar to spun fiberglass. Depending on
the size of the seed, one to two seeds should be implanted per Rockwool cube. After the seeds
have been implanted in the cubes, each cube would be soaked in a water solution mix for ten
seconds, the water is mixed with hydroponic tomato fertilizer 20- 18 -38 because it has a high
content of Calcium Nitrate and Magnesium Sulfate and potassium which nourishes the plant. The
Rockwool cube should not be put into the net cup immediately, they should be put in a container
and covered with a plastic, and they should be put in a dark area to ensure they germinate, same
as the soil plants. This same water solution mix should be used to water the soil plants, to ensure
that the hydroponics does not get an unfair advantage.
To protect the growing hydroponics plants, cover them with clay pellets so as to not let
the sun light through to the water. Only apply the clay pellets after the plants have germinated
and are at a hardy size. Clay pellets look like this:
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For the soil plants 40 plastic cups were used. The plastic cups were drilled with holes at the
bottom to ensure that the water drainage was suitable. This will prevent the plants from drying.
Each of the containers were labeled with the name of the seeds the contained inside to assure that
accurate results were recorded. The when the plants in the cups germinated they were put under
grow lights with the other germinating hydroponics. After the young plants, grew sturdy enough,
they were placed outside in the sunlight.
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As time goes by and the plants start to germinate, record which plants germinated first,
and keep constant data on the measurements of the plants in centimeters as weeks go on. Pictures
should be taken almost every day to ensure visual of the project. To ensure that no outside
conditions influence the data, make sure to keep the experiments away from young children and
curious adults as they may be tempted to touch the plants, especially the hydroponics. Check
weather conditions every day, to ensure that there would not be any rain, because this can affect
the data, if there is a chance of rain the plants should be moved inside.
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