Doctor, What Does My Plant Need?

Background Information for Teachers

There are many different types of plants on our planet (trees, bushes, grass, flowers, etc.), which all play a key role in our ecosystem. We use them for food, to make medicine, and even to build buildings. That is why it is important to make sure the plants that we grow are happy and healthy. But what is the best way to do this? Just like animals, plants have basic needs that must be met for them to live and grow. For plants, these basic needs are water, air, light, and nutrients which they get from the soil. Without all four, a plant turns brown or starts wilting and dies (Figure 1).

Image Credit: Svenja Lohner, Science Buddies / Science Buddies
Figure 1. Plants that lack water, sun, air, or nutrients die.

Plants absorb water and nutrients from the soil through their roots. The water and nutrients are then transported within the plant through tube-like structures, called xylem, all the way up to the leaves at the top. Air, or more precisely, carbon dioxide from the air, is also crucial for a plant to survive. Plants have special holes in the undersides of their leaves, called stomata, which absorb carbon dioxide from the air. This is the plant's equivalent of breathing. Light is also absorbed through the plant's leaves. Plants usually get the light they need from the sun, although artificial light from lamps can also be used to grow plants indoors.

Your students might wonder if plants need to eat like animals do. Plants make their own food (glucose, a type of sugar) through a process called photosynthesis. Water, air, and sunlight all help fuel photosynthesis. Photosynthesis is a reaction that takes place in special plant cells called chloroplasts. These cells are located in the green parts of a plant, usually the leaves, which is why light and carbon dioxide are both absorbed by the leaves. During photosynthesis, plants convert light, water, and carbon dioxide (CO₂) into oxygen (O₂) and glucose (C₆H₁₂O₆). The glucose is then stored in the plant and provides energy for the plant to grow.

In this lesson plan, students will engage in a role-play to find out how they can make an unhealthy plant healthy again. During a plant scientist consultation, students diagnose what an unhealthy plant needs to recover. As students compare plant cards for healthy and unhealthy plants, they will realize that a plant needs water, air, light, and nutrients to live and grow.

Additional Background Links

• Photosynthesis, Ducksters
• Water and Nutrient Uptake, National Gardening Association

Prep Work (15 minutes)

• Print and cut out enough of the plant cards.
• Print out the plant card symbols.
• Print out the educator symbol key.
• Print out the example pictures.
• Print out a worksheet for each student.

Engage (15 minutes)

1. Start the lesson by asking your students about their experiences with plants.

   Does anyone have a garden at home or in your community? Do you know what plants grow in your backyard?

   Have students describe the plants that grow in their gardens. Use students' answers to point out that there are many different types of plants such as trees, bushes, flowers, vegetables, grass, etc.

2. Continue the discussion.

   Have you ever helped out with the gardening?

   What did you do to keep the plants in your garden healthy and growing?

   Listen to students' replies. Emphasize responses that mention how they have watered or fertilized the plants and made sure they had enough soil and light.

3. Tell students that they will do an activity to find out what plants need to grow and stay healthy. Show them the pictures of healthy and unhealthy plants provided in the example pictures. Then discuss the pictures on each slide.

   What do you notice about these two plants?

   Let students describe the appearance of both plants and how one of the plants looks healthy (bright color, green leaves, upright stem) and the other one unhealthy (brown petals and leaves, drooping stem). See educator symbol key for more details.

   Why do you think some plants look healthier than others?

   Listen to students' answers, then explain that they will do an activity to investigate what plants need to live and grow.

4. Introduce the plant cards to your students. Show them one of the plant cards with an unhealthy plant and ask,

   What does the plant on this card look like? How could you find out why this plant is not doing well?

   Listen to student's answers and then explain that the symbols they see on the card represent everything that the plant is provided with to live and grow. Go through each of the plant card symbols and briefly explain each symbol (water, air, soil, light, friends, shelter, love, music). See educator symbol key for more details.

Explore (45 minutes)

Divide your class into student pairs. Then introduce the role-play game to your students.

1. During the role-play, students will have to figure out what is wrong with their unhealthy plant by consulting a plant scientist. The role-play will be done in pairs and includes the following steps.
   1. Every student gets two plant cards with an unhealthy plant. Each pair gets another plant card with a healthy plant to share. Point out one more time that the symbols on the cards represent everything that the depicted plant has been given so far to help it grow.
   2. One student is playing the role of the plant scientist, the other student is the person (caller) with the unhealthy plant who is consulting the plant scientist.
   3. The plant scientist gets the plant card with the healthy plant.
   4. The person with the unhealthy plant (the caller) chooses one of his/her plant cards with an unhealthy plant. Then he/she pretends to call the plant scientist to find out what is wrong with his/her plant.
   5. The plant scientist listens to the caller and asks about the condition of the unhealthy plant. The caller should describe what the plant looks like. By asking questions, the plant scientist should then find out what the plant has been given so far to help it grow. The caller will know this from the symbols given on the plant card.
   6. The plant scientist can then ask more questions and use his/her healthy plant card as a reference to find out which basic need (air, water, soil, light) the unhealthy plant is missing. Once the plant scientist finds the missing basic need(s), he/she should advise the caller on how to make the plant healthy again (by providing the missing component(s)).
2. To make it easier for your students, go through one example consultation with them. Here is an example consultation.
3. Tell students to look at their cards and then start their role-plays. Instruct them to take turns who is the plant scientist and who is the caller with the unhealthy plant. If time allows, have each student go through two unhealthy plant cards. Make sure that each time the plant scientist has the healthy plant card as reference.
4. For each consultation, let students fill out their worksheet with the missing basic needs.

Reflect (30 minutes)

1. Once each group is done, gather the whole class and discuss the following questions:

   What was easy or difficult about finding out why the plant was unhealthy?

   Did you find out what caused the plant to be unhealthy?

   How could you make the plant better?

2. Then go through each of the symbols on the plant card symbols sheet together. For each one, ask if a plant could be healthy even without that component. Make two lists for everyone to see, one for "need to have" things and one for "doesn't need to have" things.
3. Together look at the healthy plant card. Have students compare the symbols on the healthy plant card with the list of things on their "need to have" list. Then ask,

   Based on your list and the symbols on the healthy plant card, can you name the four basic needs of a plant?

   Guide students to conclude that plants need water, air, soil/nutrients, and light to live and grow, and have students fill out the respective worksheet question.

   What happens to plants that don't get all of these things?

   Students most likely will correctly say that the plant will become unhealthy and will eventually die if its basic needs are not met.

4. Have students think about how plants get all these things in nature.

   How do plants get all these things in nature? Can you give some examples?

   Encourage students to share their ideas. They might think that plants get their water from the rain or humidity in the air. Explain that plants absorb the water through their roots. The nutrients come from the soil that the plants grow in or from fertilizers and are also absorbed through the plant's roots. Light is provided by the sun or from lamps. Plants absorb light through their leaves. The air (or carbon dioxide) that plants need to live is also taken up through the leaves of a plant. Conclude that a plant can only live where they can find water, air, light, and nutrients.

   Can you think of any places on Earth where it would be difficult for a plant to survive? Why?

   Let students share their thoughts. Deserts, or the Earth's snow-covered poles are good examples of places that plants might be struggling to survive.

5. At the end, have your students summarize what they did and what they learned about plants and their basic needs.

Make Career Connections

Discussing or reading about these careers can help students make important connections between the in-class lesson and STEM job opportunities in the real world.

Plant Scientist

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Career Profile

Plant scientists study plants to find out what they need to stay healthy and to best grow. They could, for example, develop special crops that can grow with only a little water so that more food can be produced in dry regions. Read more

Biologist

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Career Profile

Biologists study living organisms, like plants, and their relationship to the environment. They do research to find out how plants function; for example, they study how they use water, light, air, and nutrients to make their own food and to grow. Read more

Lesson Plan Variations

• If your location allows, go outside and have your students look at the plants that they can find. Have them evaluate if the plant looks healthy or unhealthy. Let them find examples of a healthy plant and an unhealthy plant, then have them hypothesize what basic need(s) the unhealthy plant(s) might be missing.
• Use the plant cards for a card game with your students. Divide your class into the same student pairs again. Place one healthy plant card in the middle of the table for both students to see. This card functions as the reference for a plant's basic needs. The ten unhealthy plant cards are shuffled and put in a pile face down at the center of the table, then one of the cards is turned over and placed where both students can see it. Now each of them has to find out which basic need(s) the unhealthy plant card is missing. The first student that can identify and name them gets the card, then the next card is turned over. This continues until all unhealthy plant cards are gone. The student with the most cards wins the game.
• Experiment with different plants to see what happens when you take a basic need away. Grow plants without water, soil, or light, and compare them to their counterparts that have been provided with all their needs.