Sowing and Growing Sans Soil

"Our seventh-grade life science textbook had a couple of fascinating pages about growing plants hydroponically -- without soil," reports, New Orleans, LA, teacher Melanie Boulet. "My students were curious to discover whether we could get plants to grow without soil in the classroom," she adds, "and I saw it as an opportunity to engage the kids as problem solvers with an open-ended, real-life challenge."

With this goal in mind, Melanie charged each of several small student groups with creating a classroom hydroponics farm and using it to grow at least three different plants. She encouraged groups to brainstorm materials they might need to meet their plants' basic germination and growth requirements (e.g., support, water, nutrition), locate outside resources if necessary, then monitor the projects for a month.

Armed with aluminum pie pans, cotton balls, marbles, test tubes, tape, bean seeds, carrot tops, and more, student groups created a range of soilless growing setups. These included cotton balls in pie plates, test-tube farms, and aquariums covered with chicken-wire support. Based on information from resource books and local nursery contacts, each student group also created a "secret soup" fertilizer mix that they hoped would send their plants skyward faster than their classmates' plants.

"Students learned a lot from creating their own designs," reports Melanie. "Some had to devise ways to prop up their waterborne plants, and came to appreciate the support role typically played by soil." A number of setups had fungus problems that students believed came from the stagnant water, she relates. "They connected this experience to the pictures they'd seen of hydroponics systems that had circulating water, which sparked new ideas for how they'd like to modify their own designs," Melanie adds.

"The students welcomed the independence I gave them and the knowledge that they were forging new ground, since none of us had done anything like this before," says Melanie. "I felt that it provided a rich experience for using science and problem-solving skills to deal with real-life technological challenges." Next year, Melanie says, she'd like to have the students visit a commercial hydroponic greenhouse operation, but only after the students have had the opportunity to mess around with their own ideas and designs.

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