Give and Get-Crazy Compost

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Students will act as decomposers to create compost for the school garden!

Big Idea

Why does the nutrients in soil come from?


5 minutes

I rang my chime to get the class’s attention.  I announced that we were about to begin the sixth Science lesson in our unit about soil.  I asked them to return to the carpet squares and ‘Show Five’.  Once seated, I shared “I have a mysteryThere is something that we see every day that needs to be fed, just like you and me.  Any guesses?  I waited for answers from the class.  (Birds!  Fish.)  “No….any more guesses?”  (“Bugs?”).  “It’s soil!.”

I really like to take something students often take for granted- like soil- and make a connection to themselves.  This real life application goes a long way to immediately engage them so they want to hear what comes next.

Whole Class Instruction

15 minutes

Who ever thought that soil needs food like we do?”  “Not me!”  “A soil gets food from organic matter around it."  "Like us?"  "Exactly like us.  Now I have another question..what happens when the soil doesn’t have this source of food?”  “It grows less?”  “Close.  It's not that it grows less, it just doesn't get as much nutrients to keep it healthy.  Like in the last lesson about erosion, we learned that there are simple ways humans- us- can help out the environment.  Who wants to know how?”  “Me!!!”

We are switching jobs today.  Earlier, we were geologists because we learned about how soil was made.  Now, we’re going to be 'horticulturalists' because we’ll learn about ways to take care of soil.  When a plant grow in soil, it uses nutrients.  So the soil needs a source of continuous nutrition to stay healthy.  It gets it’s nutrients from plants when they decompose.  Different plants give different kinds of nutrients.  How many of you takes vitamins?"  "I do!!"  "It’s kind of like when you take different vitamins to stay healthy.  I’m going to show you an easy way to make the soil healthy.  It’s called…”  “Dirt vitamin?”  “Nope.  It’s called compost.”

Compost is made from plant material like leaves, old food, anything organic- that means anything that grew at one time.  Can you think of any other examples?”  “Lettuce.”  “Lettuce makes great compost because it breaks down quickly so the soil can use its nutrients.  Any other ideas?  “Fruit?”  Fruit is another perfect thing to use to start compost.  Fruits like bananas and apples have so many valuable nutrients that help balance the acid and alkaline.  It’s a way to give back to the earth and use something yucky (like rotten food) for something good.” 

To make this step easier, I collect plant material like leftover fruit and vegetables from today’s hot lunch (yes, it meant digging through some trash..with gloves!).  "We are going to take a minute to use our scissors to cut this food up into small pieces so it will quickly decompose and become compost."  When I collected the food at lunch, I grabbed several of the paper boxes used for hot lunches.  This provided an easy place to store and transport the future compost at the tables.  After the compost cutting and whole class instruction finished, I told them “It’s time for us to go outside and make some compost that we can use to help the soil be healthy.”.  Based on what we know about their environment, I think the school vegetable garden is a good place to go?  Do you agree?”  “Yes!”  I used the chime to dismiss the students by table group to line up at the back door.  

Small Group Instruction

15 minutes

Once they line up, I say “Let’s review some rules first.  First, walk in the garden.  Second, stay on the path.  Third, be gentle to the plants and each other.”  We straighten our line as I remind them “Lines are…(“straight”) “and…(“together” and..(“calm”).  We gather several clear plastic containers I prepared and put next to the back door use to carry the compost.  We begin our walk to the school garden. 

When we arrive at the garden, I model what I would do for the students by thinking out loud “What would be a good way to start a compost pileI’m going to find a box and add things that I know are healthy for soil.”.  I show how to use a scoop to pick up compost from the container, set it down in the pile, and mix it up with the existing soil.  I dismiss the children one at a time to add one scoop to the pile and mix it up a bit.  Once they do this, they join me back at the gate.  The compost collection essentially acts as a pass/fail summative assessment because they show mastery over the material by gathering and depositing material in the compost pile correctly.  The composting takes about five minutes by design since we now had an adequate amount to use for future garden activities.  I give them a one-minute warning with a hand clap pattern.  We line up again, checked our form (“straight, together, calm”) and head back.

Wrap Up

5 minutes

Once we are back in the classroom, I ask the assigned students to put the plastic containers back on the counter for any future visits to the compost pile.  After everyone washes their hands, I ask them to head back to their carpet squares.  “Let’s share some of the things we can begin to collect and add to the compost pile.”  “Banana peels”  “Old lettuce”  “Leaves”.  As each idea was shared, I added it to a list I wrote on chart paper.  After all ideas were recorded, we review the contributions before we post near the Science area so the students could refer to it during future Science lessons or drawing/writing activities.