Where’s the Dirt?

Lesson Overview
Goals
- Describe how hydroponic towers work
- Identify the key parts of the system
Outcomes
Teaching Primer
Hydroponics is quickly becoming the go-to system for urban farmers, classrooms, and small-scale farmers looking to grow indoors all year long. The system is actually quite simple but affords the grower the freedom to grow anywhere there is access to power. This flexibility opens a world of possibilities for urban use and as a solution for food deserts everywhere.
The typical vertical hydroponic system includes a well where water and nutrient solution are stored, a sump pump to move the solution to the top of the towers, emitters to drip the solution in a controlled manner, and towers that house the growing medium where the plants are positioned to receive the solution in a continuous cycle.
The management of the vertical hydroponic system is also straightforward. Growers need to introduce starts into the growing medium, maintain the proper level of nutrient solution in the bottom well, and perform general maintenance on the system between plantings. In general, the operation and maintenance of the system are simple and that makes it perfect for the classroom for Students of all ages.
Teach the Teacher
- (Video) What is Hydroponics? A brief introduction
- Inside the vertical hydroponics system
- (Video) Horizontal vs. Vertical Farming
Tools & Materials
- 1 disassembled hydroponics tower for demonstration
- 1 disassembled hydroponics tower for each group
- 1 hook for each group
- Fully assembled hydroponics table
Vocabulary
- Towers
- Gutters
- Wicking
- Emitters
- Medium
Method
Introduction (10 minutes)
Begin the lesson with the question “Can we grow food without dirt?” Make a case for growing with soil and without. Review of the vocabulary words using a disassembled tower for demonstration purposes. Be sure to mention the function of each piece and allow the Students to handle each piece. Once you have reviewed the parts, show the class how to assemble a tower and return it to the hydroponic system.
Activity (20 minutes)
Break the class into groups of 3-4 Students. Give each of them the parts required to build a single tower. Have them assemble their tower using a hook. They will struggle to get the medium into the tower without the use of the hydroponics table. Some older Students may be able to complete the assembly process.
Discussion (10 minutes)
What would make this easier? How can we use design to control the tower while we pull the medium into it using the hook? Show them the hydroponics table and demonstrate the process with the tower secured to the table.
Assessment (5 minutes)
Use the following questions to assess the Students before and after the lesson. Tally the responses of the group in the Assessment Tracking Log for comparison:
- By a show of hands, how many of you think we can grow plants without soil?
- Now that you know how hydroponics work, how many of you think you could explain to someone else how we grow without soil?
Related Lessons
Give the Intermediate or Advanced lessons a try now that you’ve completed the Beginner Lesson!
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