These two graphs display the average growth rate of the five beans per day in soil and a hydroponic system:
These four graphs (above and below) display the growth rate of each pole bean (5 pole beans in each pot) per day. The plant numbers in the hydroponic system start from the left side of the pot. The plant numbers in the pot of soil start from the right side of the pot. See above image (main image of page).
As we compare the growth rates of the pole beans growing in a pot of soil and pole beans growing in a hydroponic system, we can see that the height of the pole beans in soil fluctuates up and down much more than the pole beans growing in the hydroponic system. The reason why it seems that the plants are shrinking, is mainly because of the position of the lamp (see below under Sources of Uncertainty for more information). When we calculate the growth in percentages, the hydroponic beans grew 294% and the soil beans grew 324%.
Soil Growth
It is evident that the pole beans in soil can have large, sudden increases in height, whereas the pole beans in the hydroponic system are more consistent, usually growing 2-5 cm per day. We also see that three of the pole beans in soil have heights that are quite similar, since the lines intertwine. This is good, as the pole beans growing in the soil are mostly being kept consistent. Plant number five on the other hand, is different. At first, it started to grow normally, but then it only grew less than one centimeter after day 9. This is one day after the bottom leaves of the plant died, and could be the reason for the slow growth of the overall plant.
Hydroponic Growth
The growth rate of these pole beans are definitely more consistent than the ones in soil. Although they are consistent, the plants do vary quite a bit in terms of size, whereas the beans growing in soil are mostly all around the same height. As the number of days progresses, the height of the plants begin to vary (i.e. plant 1= 52.5 cm and plant 2 = 28 cm). There is a huge difference in numbers. (see sources of uncertainty)
Without the burnt spots, the growth rate is estimated to look like this:
(estimation is calculated by including the dry parts of vine into the total height of the plant and averaging the numbers)
Other Data and Observations
The colour and size of the pole beans growing in soil and the hydroponic system were also compared. The colours of the leaves and stem are the same, but a few of the leaves in the hydroponic system are darker than the ones in soil. Although the colours may be the same, the area of their biggest leaf is quite different. The difference of the biggest leaf from both systems is 17.2 cm (the biggest leaf from the pot of soil, is bigger than the leaf in the hydroponic system). Also, the bottom leaves from the hydroponic system were seen to have brown and yellow edges.
Discussion
Sources of Uncertainty
A main source of uncertainty about this experiment, was the lighting. It was difficult to evenly distribute lighting to all ten beans, which could have affected some of their growth. Some beans moved too close to the lamp that we used as sunlight. The result, was that part of the vines had died and dried out, due to being too close to the lamp. The best position possible, was on a stool in front of the beans. These dried parts of the vine could not be included in the measurement, but we managed to approximate the height of the beans. We looked at the average growth rate per day, measured the total height (including the dried parts of the vine), and added them together.
Another source of uncertainty, was that the wrapping vines of the beans did not wrap onto the supports when needed (they grew so long that they were hanging down, and did not catch onto something to support on, so the vine cracked). This caused the part of the vine to die and dry out. This was unexpected, as pole beans usually wrap around something to support themselves. As we measured the height, the dry part could not be included.
As the pole beans were being transplanted into the hydroponic system and pot of soil, roots were damaged, since we let the pole beans and roots grow slightly too long. This could be the reason why a few pole beans had a slower growth rate than the others. There were two pole beans that were estimated to have the most damage to the roots. These beans were plant 2 from the hydroponic system, and plant 5 from the pot of soil. Upon checking the roots of the pole beans in the hydroponic system, plant 2 from the hydroponic system had the smallest number of roots compared to the rest of the plants. Other roots were not as damaged. This means that plant 5 would also have had less roots compared to the rest of the beans. As we had five plants/samples for each of the two methods of growing beans (hydroponics and soil), the data from these plants does not have to be considered while answering the question of this experiment. We still had four plants from each, that we could compare the data with.
Without these three sources of uncertainty, we would had more consistent data in terms of growth rate. The growth rate would not have fluctuated as much, as parts of the pole beans would not have dried out and have had a higher growth rate.
Future Improvements
If this experiment were to be tested again, there would be more time allotted to fully grow the pole beans (as we could not do this), including growing other vegetables and plants (increase the sample size). We would also fix the other sources of uncertainty, such as growing the pole bean seedlings for less than 12 days, so all the roots will be intact after transplanting them to different systems, and the growth would not be affected. Furthermore, we would also construct a better and longer support for the pole beans to climb on.
Sources of Uncertainty
A main source of uncertainty about this experiment, was the lighting. It was difficult to evenly distribute lighting to all ten beans, which could have affected some of their growth. Some beans moved too close to the lamp that we used as sunlight. The result, was that part of the vines had died and dried out, due to being too close to the lamp. The best position possible, was on a stool in front of the beans. These dried parts of the vine could not be included in the measurement, but we managed to approximate the height of the beans. We looked at the average growth rate per day, measured the total height (including the dried parts of the vine), and added them together.
Another source of uncertainty, was that the wrapping vines of the beans did not wrap onto the supports when needed (they grew so long that they were hanging down, and did not catch onto something to support on, so the vine cracked). This caused the part of the vine to die and dry out. This was unexpected, as pole beans usually wrap around something to support themselves. As we measured the height, the dry part could not be included.
As the pole beans were being transplanted into the hydroponic system and pot of soil, roots were damaged, since we let the pole beans and roots grow slightly too long. This could be the reason why a few pole beans had a slower growth rate than the others. There were two pole beans that were estimated to have the most damage to the roots. These beans were plant 2 from the hydroponic system, and plant 5 from the pot of soil. Upon checking the roots of the pole beans in the hydroponic system, plant 2 from the hydroponic system had the smallest number of roots compared to the rest of the plants. Other roots were not as damaged. This means that plant 5 would also have had less roots compared to the rest of the beans. As we had five plants/samples for each of the two methods of growing beans (hydroponics and soil), the data from these plants does not have to be considered while answering the question of this experiment. We still had four plants from each, that we could compare the data with.
Without these three sources of uncertainty, we would had more consistent data in terms of growth rate. The growth rate would not have fluctuated as much, as parts of the pole beans would not have dried out and have had a higher growth rate.
Future Improvements
If this experiment were to be tested again, there would be more time allotted to fully grow the pole beans (as we could not do this), including growing other vegetables and plants (increase the sample size). We would also fix the other sources of uncertainty, such as growing the pole bean seedlings for less than 12 days, so all the roots will be intact after transplanting them to different systems, and the growth would not be affected. Furthermore, we would also construct a better and longer support for the pole beans to climb on.