What a Worm Likes
Lesson Overview
Goals
- Describe the conditions that worms need to thrive
- Perform a “squeeze test” to gauge soil moisture
Outcomes
Teaching Primer
It’s imperative to understand and be able to control the moisture in the worm bin. Worms are rather particular to their surroundings and maintaining the optimum level of moisture will ensure that the worms stay happy eaters.
Moisture has a direct impact on the oxygen that is available in the worm bin and the amount of moisture determines which type of bacteria will thrive. Because worms need bacteria to help with the digestion of food, it’s important to maintain the proper moisture level so both oxygen and bacteria are present for the worms to thrive.
In a balanced system, the moisture level should be 60%-75% to ensure that both worms and aerobic bacteria thrive.
Teach the Teacher
- The Complete Guide to Vermicomposting (included w/ Worm Factory 360)
- Browns and Greens: Understanding Carbon and Nitrogen in the Composting Process
Tools & Materials
- Established worm bin
- Moisture meter
Vocabulary
- Aerobic
- Anaerobic
- Optimum
- Bedding
Method
Introduction (10 minutes)
Begin the lesson by reviewing the role that moisture plays in the worm bin. Introduce the difference between aerobic and anaerobic bacteria. Explain how oxygen impacts the composting process and why it’s important in the worm bin.
Activity (20 minutes)
Do a smell test – Some Students may not want to use their noses to test the bins, but smell is the easiest way to detect a bin that is too wet. A small amount of bedding can be sniffed to determine if the bad bacteria have already moved in.
Perform a squeeze test – Show students how to “pinch” or “squeeze” a few tablespoons of worm bedding in their hands to test the moisture level. A few drops of water indicates a moisture level that is spot on. Any more than that is too much and indicates that the material in the bin is too wet.
Demonstrate the moisture meter – If you have a moisture meter on hand, demonstrate how to take an accurate reading with the Students. Let each of them take a reading independently.
Discussion (5 minutes)
Why is our bin too wet? How can we amend it to bring it back into balance? What is the best thing to add to absorb some of the excess moisture? What other steps could we take to balance the moisture in the bin?
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 know why the proper moisture is important to the composting process?
- Now that you understand the role moisture plays in composting and healthy worms and bacteria, how many of you could explain it to someone else?
Related Lessons
Give the Intermediate or Advanced lessons a try now that you’ve completed the Beginner Lesson!
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