HomeYouth LessonsProject S.O.W: Food Gardening with Justice in MindUnit 1: Cultivating Community1.6 The World Under Our Feet

1.6 The World Under Our Feet

Hand holding clump of soilSkill Level

Beginner, Intermediate, Advanced

Learner Outcomes

  • Learn about the importance of good soil for growing vegetables.
  • Try different hands-on techniques to learn about soil texture and pH.

Life Skills

Learning to learn, decision making, critical thinking, wise use of resources, keeping records, sharing, contribution to group, teamwork

Time

30-45 minutes

Materials

  • A few reference soil types with known textures (i.e. loamy, clayey, and sandy)
    •Sandbox sand and clay can be useful reference soil types to have to demonstrate differences in soil properties.
    •You will want to have a few sandwich bags full of each reference type for youth to look at.
  • A few soil samples from different locations (i.e. yard, community farm, community park, etc.) that youth can investigate for their various soil properties
    •You will want to have a sandwich bag full of each soil sample for youth to experiment with.
  • Soil Texture and pH handouts
  • Disposable latex gloves or a place to wash hands after handling soil
  • Tarps, newspaper, or other material to cover table if doing activity indoors
  • Clear container with lid
  • pH test kits (optional)
  • A sample of finished compost (optional)
  • Sample of potting mix (optional)

Space

Indoor or outdoor setting

Introduction

This activity is to introduce your group to what soil is and why healthy soil is needed to grow fruits and vegetables. Without soil, life on this planet would look very different. Some may say life could not exist without soil. Soil is not dirt! Dirt is what you get underneath your fingernails or track in on muddy shoes. Soil is a complex mixture of minerals, water, air, and organic matter. Organic matter (OM) consists of three main parts simply described as the living, the dead, and the very dead. The “living” OM includes microorganisms, insects, plant roots and small animals. The “dead” and “very dead” OM contains plant, animal, and microorganism residues in various stages of decomposition.  Soil provides shelter and nourishment for plants, animals, insects, and many other living organisms.

Compared to many plants we see growing ‘in the wild,’ like grass, trees, and weeds, vegetable plants are more particular about the soil in which they grow. They need a well-drained, rich soil with a neutral pH to produce lots of vegetables. Soils can be improved, and pH can be changed by adding compost and other soil amendments.

During this activity youth will learn what soil is and some ways that we can describe it. As such, please adapt this activity to what will work best for your group and garden circumstances. For example, if the group is growing an indoor garden, spend time talking about differences and similarities in potting mix (also called soilless mixes) and topsoil.

Potting mixes are specifically made to grow plants in containers and typically do not contain soil. Rather, they usually contain mixtures that can include, but are not limited to: peat moss, vermiculite, perlite, bark, coir, sand, and nutrients (e.g. fertilizer or compost).  Potting mixes are designed to retain moisture while allowing air flow around the roots and avoiding compaction. They are usually sterilized to remove diseases and pests.

Vocabulary

Soil Texture: the relative amount of sand, silt, and clay particles in a particular soil. Texture affects a soil’s ability to retain nutrients and water and helps regulate air and water movement.

Before the Activity

Collect several different soil samples. You can also ask participants to bring a zip lock bag of soil from home.

Activity

Opening Questions
  • For a beginner group new to gardening, choose from the following:
    •What words come to mind when you hear the word soil?
    •Pass around soil samples to the group. Have them describe what they see, feel, hear, and smell.
    •Hold up a bag of potting mix and a bag of topsoil. Pass around samples to the group, let them explore. Ask what similarities and differences they see.
  • For an advanced group with growing experience, ask the group if they have ever planted something in a container using potting mix, and if they have ever dug a hole in the ground to plant something. Which one is easier to dig? Which one holds water better?  Which do they think is better for long term plant growth?
Experience
  1. Set up a soil mudshake with the group. In a clear container with a lid, fill a jar ½ with water and ½ with topsoil, leave a little bit of space for air at the top. Next, shake the jar! It can be fun to pass the jar around the group and let everyone give it a shake. Let the jar rest for 5-10 minutes.
  2. Share with the group the importance of healthy, well-drained soil for growing healthy vegetable plants. Soils are complex, living mixtures of minerals, organic matter, water, air, and organisms. They provide homes and nourishment for plants, animals, insects, and much more. The mineral component of soil is made up of sand, silt and clay particles. Good soils usually have a balance of all three. Soil with too much clay or too much sand will need to be amended to make it better for growing vegetables.
  3. Carefully, have the group look at the soil mudshake. You should see the soil has settled into different components or layers. Usually, there is mineral matter at the bottom, then water, and floating organic matter at the top. Looking closely at the mineral matter, you may be able to make out different layers. Sand is the heaviest component of soil and will be at the bottom of the jar. Silt will be in the middle of the mineral layer and clay will be at the top of mineral layer.
    •Note: You should be able to see layers settle after 5-10 minutes. The longer you wait, the more distinct layers you will see. It can be fun to have the group look at the soil mudshake multiple times (e.g. after 24 hours and after one week) and count how many new layers they see each time.
  4. Share that there are many ways to figure out what is in your topsoil. Demonstrate how to do the ribbon test ribbon test to find out the soil texture type. Here is a Soil Texture by Feel Demonstration from Cornell School of Integrative Plant Science. See photos on how to do a soil ribbon test below.  Walk them through the process of determining soil texture using the Soil Texture handout.step by step instructions on how to do soil ribbon test
  5. Have them make soil ribbons and determine soil texture in groups. Have them start with the reference soils to get a good feel for the differences between clayey, loamy, and sandy soils.  Then have them make soil ribbons and determine the soil texture of the other soil samples.
  6. Ask the group if they have learned about pH before, perhaps in school or another setting. Ask the group what they know about pH.  Explain that soils have a pH and can be considered neutral, alkaline, or acidic. Talk about how soil pH affects nutrient availability. Show them the chart of nutrient availability as determined by soil pH. See if they can pick out what pH range might be best for growing vegetables. Most vegetables do best in soil with a pH between 6.0 and 7.0 with the ideal pH being 6.5.
  7. (Optional) Demonstrate how to test soil for pH. Here is a soil pH test demonstration from Cornell School of Integrative Plant Science.
  8. If testing for pH, youth can each take a turn using the pH test kit or work in groups. It can be a good idea to start with a sample that you know has a really high or low pH.  For example, peat moss is helpful for comparison as it has a low pH.
  9. For an advanced group familiar with gardening and soil, describe how to alter the pH of soils; peat moss, aluminum sulfate and sulfur are used make a soil more acidic and lime is used to make a soil more alkaline.  Talk about what amendments can be added to improve soils that have too much clay or sand. See resources at the end of this activity for more information on how to change soil pH.
  10. Discuss the soil that will be in the group’s garden. If the garden is outside and will be planted in topsoil, share with the group if any testing was done on the soil or amendments added. If the garden will be in containers, discuss what potting mix you will use and the components in it.
Reflection Questions (choose a few that work best for your group)
  • What did you think about soil before we met today? What have you discovered about soil that is new?
  • If you were to name one appreciation for soil, what might it be?
  • What are some reasons why we want to take care of our soils?

Extensions

Learn More

Acknowledgements

Parts of this activity were adapted from the NYS Seed to Supper curriculum* and Cornell Garden-Based Learning activity “Getting to Know Soil.”
References: Chapter 2 – Getting Started with Healthy Soil
* NYS Seed to Supper curriculum was adapted with permission from Seed to Supper joint program of Oregon Food Bank and Oregon State University Extension Service. Any courses based upon these materials, are to be offered equitably and free of charge.

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