![Growing Plants 3
Hydroponics is the method of growing non-aquatic plants, in a reservoir of water using a
nutrient solution that is added to the water to encourage plant growth. This is advantageous for growing
crops out of season in a green house. The hypothesis of this experiment was that plants would grow
better in hydroponics than in normal soil conditions because of the ability to control the amount of
nutrients the plants receive. According to the University of Arizona in a study of the growth of tomatoes
in hydroponics:
“The development of hydroponics has not been rapid. In the U.S., interest began to
develop in the possible use of complete nutrient solutions about 1925. [Because] Greenhouse
soils had to be replaced at frequent intervals or be maintained from year to year by adding large
quantities of commercial fertilizers. As a result of these difficulties, research workers in certain
U.S. agricultural experiment stations turned to nutrient solution culture methods as a means of
replacing the natural soil system with either an aerated nutrient solution or an artificial soil
composed of chemically inert aggregates moistened with nutrient solutions” (Hayden).
Hydroponics is a subset of hydro culture and is a method of growing non-aquatic plants, using
mineral nutrient solutions, in water, without soil. In certain situations it can be more effective to grow
plants in hydroponics then in regular soil because you can then control what kind and how much of the
nutrient solution to add to the water. The experiment was to discern whether Purple Daisies,
Osteospermum, would grow better in a hydroponics kit then in regular soil conditions. According to
studies completed by institutions such as the Delaware Valley College;
“Hydroponics is the scientific frontier of agriculture, which sustains human life on Earth.
The challenge is to meet the world’s food needs while preserving Earth’s natural resources. At
the same time as we are concerned with hydroponic food production on Earth, the US National
Aeronautics and Space Administration is also committed to this new technology to cultivate](https://image.slidesharecdn.com/growingplantsviahydroponics-120612074107-phpapp02/85/Growing-plants-via-hydroponics-3-320.jpg)
Growing plants via hydroponics
- 1. Growing Plants 1 Growing Plants via Hydroponics By Sandra Cash & Hannah Peterson Dr. Thomas Crown College General Biology, Section 112 30 April 2012
- 2. Growing Plants 2 Abstract This article first defines hydroponics and relates the history of hydroponics. Secondly, this article describes the various methods of hydroponics. Next, this article talks about a few of the problems hydroponics has compared to problems with cultivation in soil. Then, it goes over Sandra Cash’s and Hannah Peterson’s experiment to determine which method of growing plants is better, hydroponics or soil. Lastly, it goes on to talk about the results Sandra Cash and Hannah Peterson found through their experiment.
- 3. Growing Plants 3 Hydroponics is the method of growing non-aquatic plants, in a reservoir of water using a nutrient solution that is added to the water to encourage plant growth. This is advantageous for growing crops out of season in a green house. The hypothesis of this experiment was that plants would grow better in hydroponics than in normal soil conditions because of the ability to control the amount of nutrients the plants receive. According to the University of Arizona in a study of the growth of tomatoes in hydroponics: “The development of hydroponics has not been rapid. In the U.S., interest began to develop in the possible use of complete nutrient solutions about 1925. [Because] Greenhouse soils had to be replaced at frequent intervals or be maintained from year to year by adding large quantities of commercial fertilizers. As a result of these difficulties, research workers in certain U.S. agricultural experiment stations turned to nutrient solution culture methods as a means of replacing the natural soil system with either an aerated nutrient solution or an artificial soil composed of chemically inert aggregates moistened with nutrient solutions” (Hayden). Hydroponics is a subset of hydro culture and is a method of growing non-aquatic plants, using mineral nutrient solutions, in water, without soil. In certain situations it can be more effective to grow plants in hydroponics then in regular soil because you can then control what kind and how much of the nutrient solution to add to the water. The experiment was to discern whether Purple Daisies, Osteospermum, would grow better in a hydroponics kit then in regular soil conditions. According to studies completed by institutions such as the Delaware Valley College; “Hydroponics is the scientific frontier of agriculture, which sustains human life on Earth. The challenge is to meet the world’s food needs while preserving Earth’s natural resources. At the same time as we are concerned with hydroponic food production on Earth, the US National Aeronautics and Space Administration is also committed to this new technology to cultivate
- 4. Growing Plants 4 crops in space, which is vital to human exploration of the Moon and Mars” ("Delaware valley college," 2011). Hydroponics is an alternative for plant growth, but it is not without its own drawbacks. With hydroponics, there is the possibility that the plants can contract disease such as Pythium aphanidermatum, a water mold that infects young plants and slowly kills them. It is increasingly difficult for those that work in greenhouses, because it favors warm and damp conditions (Parker). Doctor Timothy Shelford at Cornell University has studied some risks of growing plants in hydroponics: “Pythium aphanidermatum has been identified as the main obstacle/risk in the production of hydroponically grown baby leaf spinach. This organism is so prevalent that even crops grown in fresh nutrient solution will often show signs of Pythium damage at harvest time” (Shelford, 2010). Before starting this experiment, the hypothesis was that the purple daisies would grow better and faster in the hydroponics kit since it allowed for the control of nutrients and therefore control of the growing conditions. Twelve individual daisies were grown, six in regular soil and six in the hydroponics kit and all were monitored over two months. A container holds about six gallons of water with two teaspoons of nutrient solution for every gallon of water. Six plant containers are placed down in the nutrient solution. An aquarium air pump constantly bubbles in the nutrient solution, keeping the plants’ roots from drowning. Clay pellets fill the planters and allow the water to reach the plants without the plants being so deep in the planter so that sunlight cannot reach them. Aside from the planters, the rest of the container is covered to block the nutrient solution from being exposed to sunlight; this is to ensure that algae does not begin to grow in the hydroponics kit.
- 5. Growing Plants 5 During the course of the experiment, seeds were first kept watered and under artificial lights to stimulate growth, after the roots became large enough to support themselves all twelve plants were moved into larger planters and the plants going into the hydroponics kit were totally removed from soil. After one week in the new planters, the soil grown plants began to look healthier then the hydroponics plants. After two more weeks the soil plants continued to look healthier than the hydroponics plants, but watering for the soil plants was increased from 50 ml to 60 ml. After three weeks, the soil plants continued to improve, though plants did not appear to be as large as they should. The plants in the hydroponics kit still looked unhealthy, especially the three farthest from the sunlight. The water in the hydroponics kit was quickly changed, and three teaspoons for every gallon of water was added to the nutrient solution to encourage plant growth. Two weeks later showed continued improvement with most of the soil plants, but three were withered and dead looking. The water level in the hydroponics kit was low, so about 50 ml of water was added directly to each plant. The three plants farthest from the sunlight were dead. These experiments took place in the Chemistry lab in Crown College from February 21, through April 17, 2012. Results of this experiment were inconclusive and more data is needed to make an informed conclusion. Half of the hydroponics plants died due to the lack of sunlight, since the planters shaded them. The three hydroponics plants that did survive grew extremely slow, to about one inch in length. The soil plants did better, although half of them also died due to unknown reasons. The surviving soil plants grew faster and developed multiple stems and leaves. The soil plants grew to about three to four inches, and looked healthier than the plants in the hydroponics kit.
- 6. Growing Plants 6 The results of the experiment could have been affected by the two weeks needed for the hydroponics kit to be shipped from the company, and another two weeks for the setup of the kit. All results were based on a month given to the growth of the plants from the time available. Based on the results of this one experiment it appears that hydroponics are not better for plant growth, but when data from other existing experiments is added, the results are more in favor for hydroponics depending on the type of plants grown. Hydroponics is mostly used to grow crops such as lettuce, tomatoes, and other leafy green plants (Schmidt). Flowering plants have been grown using hydroponics before, but it is much more difficult and the time needed for growth is much longer. If the experiment is repeated it would be best to try two or three species of plants for a variety and so that the results are not skewed in any way. It would also be prudent to allow more time for plant growth or to use faster growing plants. Pre-grown plants would be a way to examine whether or not hydroponics keeps the plants healthier than plants in soil conditions. It would also improve results if an artificial lighting system was set up above the plants so that the results are not based on a differing amount of light each plant receives.
- 7. Growing Plants 7 Another way that could be used to improve the results would be to use a different hydroponics kit that would allow differences on how the water reservoir is used. There are five different types of hydroponics kits available for commercial use at this time. According to professors at the University of Illinois at Urbana-Champaign, there are four main systems that are effective for plant growth (Schmidt). The first is the simplest and probably the most well know method known as the water culture, reservoir method, and the aquaculture method. This method involves totally immersing the plant roots in a nutrient solution mixed with a large amount of water. Next is the Aggregate Culture method that has the plant roots buried in sand or gravel and a supply of nutrients and water are added to the container when needed. This method is effective because the sand/gravel support the roots. Aeroponics is another, more complicated way to grow plants. This method has the roots totally exposed in an airtight container and constantly misted with a nutrient/water solution. Lastly, there is the continuous flow system, which has the roots planted plastic piping, such as polyvinyl chloride (PVC) pipe, commonly used for household waste plumbing, to allow a steady stream of nutrient/water solution to constantly flow over the roots. A water pump is connected to the pipe and to a large water tank, this allows the nutrient/water solution to be recycled and reused. In conclusion, hydroponics is a good alternative for soil grown plants when the hydroponics kit is used correctly and plants receive regular water/nutrient solution. While there are risks, they are less obvious and there is less worry about parasites and diseases then with soil grown plants. Also, it is important that someone who is interested in growing plants in a hydroponics kit, research the information very carefully and totally before buying a kit. It is also important to know what species of plants grow best in hydroponics conditions, and how they will respond to the various nutrient solutions.
- 8. Growing Plants 8 References Delaware valley college. (2011). Retrieved from http://www.delval.edu/pages/nrbm/C1104/ Hayden, A. N. (n.d.). hydroponic tomatoes. Retrieved from http://ag.arizona.edu/hydroponictomatoes/history.htm Parker, K. (n.d.). Pythium aphanidermatum. Retrieved from http://www.cals.ncsu.edu/course/pp728/Pythium/Pythium_aphanidermatum.html Schmidt, J. (n.d.). Hydroponic systems. Retrieved from http://www.aces.uiuc.edu/vista/html_pubs/hydro/hydroponic.html Shelford, T. (2010). The risk of pythium aphanidermatum in hydroponic baby-leaf spinach production. Retrieved from https://ecommons.library.cornell.edu/bitstream/1813/17229/1/Shelford, Timothy.pdf