Cabbage Growth in Hydroponic Systems
Rational
This report is on the growth of cabbage in different hydroponic systems. A hydroponics system is an
agriculture system that grows plants without soil (Woodard, 2019). The hydroponics systems that
were used in the report were, greenhouse solid media, outside solid media, and NTF Pipes. A dripper
line was also used to compare to the conventional method of soil and water, this acted as a sort of
control. Without the use of soil in hydroponic systems soil-borne diseases and pests are removed.
This then means there is no need to use large amounts of pesticides.
For a plant to grow they need the right temperature, light, water and nutrients. (Needs of Plants ,
2019) With some of the hydroponics systems, these requirements for plant growth are further
enhanced. The temperature inside a greenhouse is hotter so this helps plant growth as well.
Greenhouses are used because of the benefits that have on the growth of plants and because of
how they offer protection from the elements. When hydroponics is used erosion and water/air
pollution are reduced (JOHNSON, 2010). Hydroponics is useful because of the large number of
benefits and the ability to produce a lot of produce in a small amount of area. This can be especially
useful in dense areas like the city.
Hypothesis
Therefore, the hypothesis for this research task is that- Cabbage will grow best in the greenhouse as
a greenhouse enhances many of the requirements for plant growth.
Research Question
The final research question that has been chosen to investigate is- What effect will changing the
hydroponics system (Greenhouse solid media, outside solid media, NTF Pipes, Dripper line) have on
the growth of cabbage?
Methodology
The following dot points are the steps that were undertaken to complete this experiment
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Planted the seedlings in the different systems on the same day
Set up the hydroponics so they are receiving their nutrient solutions
Place the dripper line on the soil
Let them grow for 6 weeks
Measure the plant heights and width
Let the plants grow for another week
Measure heights and weights
Record heights/widths and produce averages
Analyse the findings
Risk Management
Although there weren’t a large number of risks in this experiment, there were still a couple of
important ones. The first risk is the risk of getting electrocuted or having faulty equipment that can
cause problems. This risk was managed by using safety switches on all of the electrical power points
and tagging the old equipment. The other risk is the consumption of the nutrient solution liquid. This
is managed by washing hands after working with the vegetables and having signs on everything
poisonous and harmful.
Results
The table below displays the heights and widths of cabbage at 6 weeks old.
Data
System/plant
number
Greenhouse
solid media
Outside solid
media
NFT pipes
Dripper line
1
2
3
4
5
Width: 235
Height: 475
Width: 220
Height: 345
Width: 165
Height: 186
Width: 178
Height: 313
Width: 192
Height: 452
Width: 210
Height: 350
Width: 86
Height: 123
Width: 200
Height: 352
Width: 200
Height: 430
Width: 184
Height: 339
Width: 96
Height: 178
Width: 196
Height: 301
Width: 240
Height: 470
Width: 185
Height: 290
Width: 136
Height: 170
Width: 174
Height: 268
Width: 242
Height: 512
Width: 175
Height: 279
Width: 156
Height: 170
Width: 180
Height: 280
This table shows the average heights and widths at 6 weeks and average weights at 7 weeks
Greenhouse solid
media
Outside solid
media
NFT pipes
Dripper line
Average height
468 mm
321 mm
165 mm
303 mm
Average width
185 mm
162 mm
128 mm
Average weight
418 g
204 g
157 g
186 mm
184 g
The table below shows the standard deviation of both the heights and widths for the hydroponic
systems
Standard
Deviation- Height
Standard
Deviation- Width
Greenhouse solid
media
Outside solid
media
NFT pipes
Dripper line
30.4
33.4
24.6
32.6
23.9
19.2
35.4
11.6
The graphs below show the average width and height, and average weight
Length (mm)
Graph of Cabbage Growth in Different
Hydroponics Systems
500
400
300
200
100
0
Green
house
solid
media
Outside
solid
media
NFT
pipes
Dripper
line
Hydroponic system
Average height
Average width
Weight (g)
Average weight
500
400
300
200
100
0
Green
house solid
media
Outside
solid media
NFT pipes
Dripper line
Hydoponic System
All of this data was processed using Excel functions to calculate averages, totals and the standard
deviation.
Excel was also used for the creation of all of the graphs. Some observations were made whilst
collecting the data, including:
Greenhouse solid media- Very large and thick cabbage plants compared to all the other systems
Outside solid media- The front ones were bigger than the back
NFT pipes- Plants were very small compared to the others and there was a large variation
Dripper line- Some variation in the height of the cabbage but not much in the width.
Analysis of Evidence
This evidence shows how all of the hydroponic systems compare to one another. A trend that was
evident throughout all of the evidence was how the greenhouse solid media had great results all
around. It had the highest average width and height along with a small standard deviation. The NFT
pipes had the worst growth every time compared to all of the other systems. The standard deviation
of width in the NFT pipes was noticeably higher than all of the other systems. The standard deviation
was 35.4 which shows that the system was quite variable. The standard deviation of both the width
and height in the dripper line was quite low compared to the other systems, showing that all of the
numbers were quite close to the mean. This means that the growth of the cabbage was consistent
throughout all of the 5 cabbage plants grown in the dripper line system.
This data fits the research done about the benefits of greenhouses. The temperature, which is an
important part of plant growth, was hotter in the greenhouse. This supports the research presented
in the rationale. The hypothesis that was presented was correct as the greenhouse had the best
plant growth.
The answer to the research question is- In changing the hydroponic system there will be a variation
in the results of plant growth. A greenhouse solid media and outside solid media will be beneficial
and provide better growth than an ordinary dripper line. Whereas an NFT pipe will not provide
benefits and will have less growth on the cabbage than a dripper line, as seen in the results.
Evaluation of the Experimental Process
Throughout the collection and presentation of the evidence, there was a varying quality with some
sources of error. The averages in the evidence section were determined by calculating the sum of
the numbers divided by the total number of values in the set. There were a few sources of error in
the report which impacted the results making it less valid. One of the sources of error was that all of
the cabbages were only half-grown when they were measured. This is because the final
measurement was done when the cabbages had been growing for 7 weeks and it takes a cabbage
12-20 weeks to reach the full-grown stage (RHS, n.d.) Some of the systems could have had cabbages
that would have caught up in growth had the cabbages been fully grown. Another source of error is
that different scales were used to measure the weight. One of the scales is also reportedly faulty
meaning that some error in the data could have happened. A way to stop this is to use the same
scale the whole time and to make sure it is calibrated.
If this topic was to be explored further some extensions could be made to provide further insight
into this topic. The first extension is experimenting over a longer time so that it allows the cabbages
to fully grow. This would then give a better comparison of how well hydroponics works. The second
extension is the time of the year when the experiment is being conducted. If the experiment is
conducted at a more ideal time of the year for cabbages, like winter, then it would provide further
insight into the benefits of using hydroponic systems.
Conclusion
There are many benefits when using hydroponics to grow vegetables. This includes better protection
from the elements, greater control over what nutrients the plants get, and less use of herbicides.
Out of 3 different hydroponics systems (Greenhouse solid media, outside solid media, NTF Pipes)
and a control (dripper line), cabbage grew best in the greenhouse solid media. The experiment was
fairly accurate but there were some sources of error like, the cabbages were only half-grown and
different scales were used to measure the weight. Based upon the evidence gathered throughout
the report it can be concluded that changing the hydroponics system can have better results on the
growth of cabbage, like in the greenhouse solid media, or worse results, like the NFT Pipes.
Bibliography
JOHNSON, L. (2010, December 3). WHY USE HYDROPONICS. Retrieved from Ezgrogarden.com/:
https://ezgrogarden.com/hydroponics/why-use-hydroponics/
Needs of Plants . (2019, August 21). Retrieved from Letstalkscience.ca:
https://letstalkscience.ca/educational-resources/backgrounders/needs-plants
RHS. (n.d.). Cabbages. Retrieved from Rhs.org.uk:
https://www.rhs.org.uk/vegetables/cabbages/grow-your-own
Woodard, J. (2019, September 6). What Are Hydroponic Systems and How Do They Work? Retrieved
from Freshwatersystems.com: https://www.freshwatersystems.com/blogs/blog/what-arehydroponic-systems