Learning Hydroponics

Aleda Vaughn first became aware of hydroponics in her sophomore year in high school. Students in her agricultural class were shown a small hydroponic growing unit in the school greenhouse. She was amazed to learn that plants could be grown without any soil at all. Her family had often grown their own fresh garden vegetables, but always in soil.

An agricultural student and a very active Future Farmers of America (FFA) club member Aleda wanted to learn about hydroponics, and she was interested in competing in the National Competition for FFA science projects.

The competition would not be easy. She would start by suggesting a hypothesis, designing and conducting an experiment, collecting data, then writing a science paper and presenting her findings in a science fair. She would then submit the work to a state competition and, if she won, she could go on to the Nationals. She really wanted to make Nationals.

By the time the science project was completed, Aleda had logged in 146 hours of work, both in design and implementation phases and writing a scientific paper. Her work won the California FFA competition, so she qualified to take it on to the Nationals in Louisville, Kentucky, where the science projects were judged on October 27th at the annual National Convention of the Future Farmers of America.

There were 17 science projects submitted in Aleda’s botany category, and there would be only three awards, First, Second and Third. When Aleda set up her poster, scientific paper and log book with data and notes, she looked over the competition and was feeling certain that she was one of the top four. She hoped for at least a third prize, even though she had trouble with experiment because most of the plants died before the completion of the four week timeline.

Aleda’s paper for the competition begins with a quote from her local farmer magazine. “Imagine California’s Central Valley – the richest agricultural area the world has ever known – not being able to produce enough food to feed its own people in just one lifetime from now.” The article writer predicts that 60% of the valley floor will be urban by the year 2080. Aleda based her introduction on this quote, pointing out how hydroponics can be an answer to this reduction in available farmland.

Aleda had more problems when describing problems relating to control of insects. All of the lettuce plants in her experiment contracted aphids brought onto the plants by ants. Aleda noted in her findings that there were less aphids on the lettuce plants being grown in gravel. She speculated that it could be due to ants having a harder time crawling over ¾” pieces of gravel with an aphid on their backs. She mentioned that she thought it would be an interesting hypothesis to investigate.

So what was this experiment and why did Aleda have so much trouble? When asked if she faced any challenges during the experiment Aleda laughed, interlaced her fingers, placed her hands on the table and said, “How many would you like?”

Aleda tried to test four types of media to determine which would be the best to grow lettuce in a recycle system. She decided to test vermiculite, pumice, gravel and rockwool. When she set up the experiment her agricultural teacher told her to use Miracle Grow as the nutrient for the hydroponic system.

Before the experiment could begin, a Bunsen burner left on in the greenhouse caused a fire that delayed the experiment by two weeks. When she could finally begin, the new schedule required she could run the experiment for two weeks when she could take data, and then two weeks when she would be on a field trip. The nutrient tank only held enough water for 1.5 weeks. The person she asked to refill the tank forgot, and her plants went without water for the last three days of the experiment.

Out of the initial eight plants in each growing media, none remained in the pumice and only two remained in the each of the other three media. Her results showed poor growth in all of the media.

In the first week of the experiment, Aleda’s plants showed significant death rates. The consistent death of plants in the experiment would have been a clear sign to a hydroponist that something was wrong, but Aleda is new to hydroponics and is only familiar with raising soil based plants. She had no way of knowing that plants in hydroponics, when in a properly managed system, grow and thrive and hardly ever die.

In the second week of the experiment, Aleda found aphids on her lettuce starts. Aleda knew that ants were bringing aphids to her plants. Ants carry the aphids on their backs and then carefully place them on plants. Later the ants will return and milk the aphids of their sweet honeydew secretions.

Aleda worked to control the ants and then successfully removed the aphids. But her plants probably had suffered from the attack and she had more plant death. She learned through this experience that insect attack should be prevented before and during the experiment with barriers, preventive sprays and careful monitoring.

Aleda did note in her conclusions that the lettuce plants in gravel suffered the least from the aphids and speculated that it might be more difficult for an ant with an aphid on it’s back to navigate over the pieces of ¾” gravel. She suggested that it would be an interesting study to look at the possibility that some media would be less vulnerable to insect attacks.

Nevertheless, the insect attack is a normal problem in hydroponics and she was able to use the event to perceive that the top of the media could influence insect invasion. So the insect attack was a learning experience.

But the use of Miracle Grow as the hydroponic nutrient probably caused significant plant death and did not provide Aleda with a working hydroponic system that could be successfully used to test growing media.

So why did Aleda’s teacher tell her to use Miracle Grow. In fact, there is a controversy if Miracle Grow can be used as a hydroponic nutrient. While hydroponics experts are pretty much in agreement that it will not work, there are hobbyists that are claiming that it does work. A simple internet query on hydroponics and Miracle Grow will bring up the controversy with some people claiming that “those expensive nutrients are not worth it and not necessary in hydroponics. Just use Miracle Grow.”

The science of hydroponics would find that Miracle Grow 15-30-15, designed to be a foliar spray and a fertilizer for use in soil, is missing four of the minerals needed for plants. A standard hydroponic nutrient should provide all 13 necessary minerals, in forms that the plant can use.

A hydroponic nutrient can also be engineered to maintain a steady good pH in the system, and it can be designed to provide specific portions on minerals to optimize growing or blooming stages of plant growth. There are current efforts to design a nutrient that is best for root growth.

According to Simon Lennard, author of Nutron 2000, a hydroponics nutrient software program, the fact that Miracle Grow is a one part fertilizer is a strong indicator that it will not be a good hydroponic nutrient. Almost all hydroponic nutrients come in at least a two part formula.

As Simon explains, “Hydroponic nutrients generally need to be ‘2-part’ mixes, and simple plant foods are unsuitable. The reason for this is that calcium and sulfur can not exist in solution in a concentrated form, as calcium sulfate is produced and causes the calcium and sulfur to ‘precipitate’ (or form into a white powder on the bottom of the tank). As Simon explains, “Once precipitated, the nutrients are no longer available in solution for plant uptake. By avoiding calcium nitrate and magnesium sulfate (the common sources of these ions for conventional hydroponic nutrients) a ‘one-part’ mix can be achieved. While quite suitable for soil or supplementary feeding of pot plants, it is inadequate and very unbalanced as a hydroponic nutrient.”

Aleda used Miracle Grow as her hydroponic nutrient and had significant plant death throughout the experiment. She completed her science experiment, won in California, showed it at Nationals, and the use of Miracle Grow was never questioned. Neither judge asked any questions about the picture of lettuce that showed poorly formed discolored leaves, and significant plant death throughout the experiment.

Miracle Grow is missing key ingredients like calcium and magnesium. If a plant grows in soil, calcium is usually available, but in a hydroponic system, the plants would be starved of calcium. The plants would die rapidly if calcium was not available, and plant death would be expected. So, the analysis of Miracle Grow as a hydroponic nutrient is that it is not sufficient.

So why the controversy that Miracle Grow does work?

In every hydroponic system, there is a combined system of the nutrient used, the growing media, the growing container and the water supply. It is possible that the missing minerals could be present in growing media, water supply or perhaps even the container. Calcium would be available in very hard water. If Miracle Grow does successfully produce hydroponic plants, it would be on the off chance that the growing media or the water would supply the missing elements.

Even if a full system can supply the missing elements, there are still problems with Miracle Grow that will cause problems in a hydroponic system. If it did not appear in the short term, it would probably appear over time. The label on Miracle Grow guarantees that the chlorine content is not more than 12.5%. Simon points out that the reason there is so much chloride is that it is in some of the chemical forms. Some chloride can accumulate in solution displacing other nutrients over time.

Aleda’s use of Miracle Grow is not unusual for elementary or high school hydroponic experiments. An experiment for elementary schools on the internet tells the teacher to use Miracle Grow. Apparently it is not unusual for a new hobbyist to try Miracle Grow, and even some testing of larger research facilities have made the same assumption.

Aleda did not receive any prize for her experiment, and she was “sort of bummed about it.” There were two other experiments using hydroponics in the competition. Another received no prize but a third that compared flow rates to productivity received a blue ribbon. It was a project presented by two middle school girls.

Aleda has now gone on to community college. She decided to skip her senior year in high school, taking a California proficiency test instead. She is now in her first semester taking calculus and beginning her education to go into either animal science or plant science.

Her project in hydroponics was a significant learning experience for her. She learned about the scientific process and she learned a great deal about the structure and language of writing a scientific paper. And her belief that hydroponics is necessary and an important technology for the future has not been dampened by the problems she experienced during her experiment.

She did express regret that she has now been experimenting with hydroponics for two years and has still not produced a single tomato or lettuce leaf she can take home to her family as evidence of her work. The tomatoes had to be pulled before any fruit had ripened and the lettuce did not survive.

Aleda’s faith in hydroponics for future agriculture remains unshaken. She is sold on using hydroponics for any plant experiments. “It is an excellent tool because in a confined area you can control everything except the one minute variable you wish to investigate.”

She is not sure if she will pursue hydroponics in her career path. Her first love is animal science and she would like to be a veterinarian. A champion horsewoman among her other interests, she considers plant science her second choice of a career path.

However, Aleda’s interest in growing her own food hydroponically remains and she is likely to begin producing her own hydroponic food. As a vegetarian she has an interest in high quality fresh vegetables and food that is pesticide and herbicide free. In fact Aleda feels we might all look at growing some of our own vegetables. “During the Second World War the President called upon women to start Victory Gardens and they produced a substantial portion of the fresh vegetables during the war years.” She smiles as she points out, “That shows it is possible.”

She also has faith in hydroponics being an essential method of producing food in our farms of the future. “Empires rise and societies fall, but people will always need a stable source of food.”

Aleda’s experience is, perhaps more than anything else, a lesson to those who provide agricultural education and those who seek to teach hydroponics. In this experiment the student, and the plants were never given a fighting chance because Miracle Grow is not a hydroponic nutrient. She should have been able to start her experiment with a working hydroponic system, so the variable she desired to test, different media, would be the variable tested. As it stands, her experiment more clearly shows that Miracle Grow does not work