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What is Compost?

Sarah Heidtke, Dakota County Master Gardener Volunteer

Have you seen signs around that say “Compost?” Maybe you’ve put bags of compost on your gardens already. Maybe you even have your own compost at home! What is compost? Read on with your curious child to find out what goes into this helpful mix and how we can help plants grow (and keep organic matter out of our landfills!)

What is Compost?

I think of compost as a really nutritious casserole or lasagna for plants. Did you know that plants need good nutrition, just like people?

First, let’s talk about organic matter. Things that once grew as plants - grass clippings, fallen leaves, banana peels, even paper towels - can break down and become food for new plants when we add them back into the soil. Microbes are tiny living organisms that help break down this future compost. The best way for us to set this up is to layer “green” organic waste and “brown” organic waste (like we layer yummy ingredients between noodles in a lasagna!) So let’s start there:

Examples of “green” organic matter: raw fruit and vegetable peels, egg shells, grass clippings, plant trimmings, tea bags, and coffee grounds

Examples of “brown” organic matter: straw, twigs, shredded newspaper, paper towels, brown leaves, sawdust

When the helpful bacteria, tiny microbes, worms and bugs start eating and mixing our green and brown layers, the layers start to break down and even make energy. The goal is for the pile to get warm enough to “cook” out the kinds of germs that get stinky or make us sick. It’s just like we cook some of our foods to make them safe and tasty for us to eat. People can help things along by turning over the mix - this helps it break down evenly and adds oxygen and moisture to encourage the process. If the weather gets really dry, spray down the pile with water now and again between rain showers.  It can take some patience, but eventually you will have fresh compost ready to mix into your planting soil!

Where does this happen? Sometimes community compost sites make BIG batches of compost after they collect organic waste from many places. This could be from compost bins near the trash and recycling cans like these - see the one that says “COMPOST?” Or, Dakota County (as well as other counties) has a program where residents can bring their food waste in special biodegradable bags to a public site like this one at the Holland Lake parking lot of Lebanon Hills Regional Park.  

See this website for more information on Dakota County’s Organics Drop Off program

Some people make compost right at home! You can buy a compost bin made just for this purpose through many vendors online or through Dakota County  Or you can make your own! 

Here are some helpful websites with instructions for making a home compost bin (with an adult!):

You can even take a class with the Minnesota Landscape Arboretum for a compost bin building demonstration here:

Here’s a 3-part system of compost at the Arboretum’s Children’s Garden:

The older organic materials get moved “next door” to make room for new green and brown layers in the first section.

If you haven’t checked out the Green Play Yard and learning garden next to the Marion Andrus Learning Center there yet, I truly recommend it - it’s fantastic!

So kids, let’s review - what’s compost?

Organic matter made from plants that helps plants grow! It adds nutrients and texture to the soil so the plants can get oxygen and water through their roots. Compost that’s ready for this job should not have a stinky or rotten smell.

How can kids help to make compost?

  • Help collect food waste like peels, coffee grounds, tea bags, greens and egg shells that won’t get eaten into a container until it is full and ready to take to your home or community compost site. Toddlers and older can carry a closed pail or small bag of organics and participate in the cycle of their food.

  • Gather black and white newspapers, brown cardboard and paper towels (shredded to help them break down faster), sticks, and leaves for the brown layer at home.

  • Use a large garden fork or shovel to stir up your compost pile now and again, or use the handle on some bins to turn the pile around. It’s not an exact science, so put those growing muscles to work mixing things up!

  • Keep an eye out for helpful signs at parks and businesses that show you where to put compostable items and keep them out of the landfill.

For a great factsheet about home composting, see this link from the Minnesota Pollution Control Agency

Book Time! Read on at Dakota County Libraries for more kid-friendly information about COMPOSTING:

Compost Stew: An A to Z Recipe for the Earth by Mary McKenna Siddals and Ashley Wolff, recommended for Ages 2-6

Garbage Helps our Garden Grow: A Compost Story by Linda Glaser, recommended for Ages 6 & up

Photo Credit: Minnesota Pollution Control Agency Website (2), Sarah Heidtke (1,3,4,5,6) , Compost Stew: An A to Z Recipe for the Earth by Mary McKenna Siddals and Ashley Wolff (7) & Garbage Helps our Garden Grow: A Compost Story by Linda Glaser (8)

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