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    Plant Nutrition Experiments

    This experiment is courtesy of 


    Mary Lou Corrigan
    Newtown Elementary School
    1 Wrights Road
    Newtown, PA 18940

    Joanne C. Letwinch
    J. F. Tatem Elementary School
    1 Glover Avenue
    Haddonfield, NJ 08033

    Diane L. Antes
    Rohm and Haas Company
    727 Norristown Road
    Spring House, PA 19477-0904

    Dr. Tirthankar Ghosh
    Rohm and Haas Company
    727 Norristown Road
    Spring House, PA 19477-0904


    Grade Level:

    3 through 5



    General Science - Plant Biology and Chemistry



    1. Students will observe the growth of a seed.

    2. Students will predict what will happen when seeds are planted without soil.

    3. Students will conduct an experiment using a hydroponic system.

    4. Students will compare/contrast seedlings planted in a fertilizer component with a control system of plain water.

    5. Students will draw conclusions about plant growth using hydroponics and nutrient components.



    In this activity the students will:

    1. measure and record the growth of plant roots and stems.

    2. use a variety of methods to collect and record plant data.

    3. explain the influence of fertilizer and its components on plant growth.

    4. use math skills to interpret graphs and charts.

    5. practice the process skills of observing, predicting, measuring, and hypothesizing.


    National Science Education Standards:

    Content Standard A: Science as Inquiry:

    • As a result of activities all students should develop the abilities to do and understand scientific inquiry:

      1. Students should participate in experiences that allow them to develop ideas and explanations, investigate materials, and develop vocabulary and questioning skills.

      2. Students should develop the ability to ask questions, communicate their ideas, plan and conduct simple investigations, use simple scientific equipment, and apply data to formulate and transmit reasonable conclusions.

    Content Standard B: Physical Science:

    • Students should develop an understanding of the properties of matter and how these properties may be effected by solubility or chemical change.

    Content Standard C: Life Science:

    • As a result of activities in grades K-4 all students should develop an understanding of:

      1. the characteristics of organisms and their basic needs such as food, water, air, and, in the case of plants, nutrients and light.

      2. the relationship between organisms and environments.

      3. the fact than an organism's performance is connected to the characteristics of its environment which includes the types of food and other resources available. Changes, which may be either beneficial or damaging to an organism, may occur as a result of its environment. The focus in the classroom for grades K-4 should be to develop the connection between an organism and its survival to its environment.

    • As a result of activities in grades 5-8 all students should develop an understanding of:

      1. the management and behavior that occurs within an organism in relationship to its environment.

      2. the process of an organism's ability to adapt to its environment in order to survive.

      Adapted from: National Academy Press/National Academy of Sciences website


    Background Information:

    The motivation for this experiment was to develop the understanding that different mineral deposits located in a plant's growing area can effect its growth. We know that more than 100 elements can be found in the earth's crust, and all of these elements can be found in plants from different areas, but there are a few essential minerals that all plants need to grow successfully.

    The usual source of these elements is the soil. However in 1860, two plant physiologists, Sacks and Knop, demonstrated that many different types of plants could be grown from seedlings to maturity in a water solution containing a few salts. Ever since these first successful water, or hydroponics, experiments, the technique has been constantly improved and successfully used in the study of problems of plant nutrition. Hydroponics is used because it is believed that feeding nutrients directly to the plant's root system allows for healthier plants since the roots do not have to search for the nutrients and water. The nutrients most often found in hydroponics mixtures are: nitrogen, potassium, calcium, magnesium, iron, sulfur, and traces of zinc, manganese, copper, and iron.

    Plants require thirteen mineral nutrients for growth and completion of their life cycle. Four are needed in higher concentration, and the remaining are only trace elements. We will concentrate our experiment on the four major nutrients needed by the plants for healthy growth.

    Fertilizer studies are based on careful analysis of plant needs and are carried on in all parts of the world where plants are grown for food and industry. Fertilizer numbers are based on the essential nutrients a plant needs. For example, if the fertilizer package reads (15-3-3), the first number is the percentage of nitrogen for plant leaf growth, the second number is the percentage of phosphate for fruit or flower growth, and the third number is the percentage of potash (potassium carbonate) for the root growth.

    Essential nutrients are defined as those:

    1. without which the plant cannot develop normally or complete its life cycle.

    2. for which no other nutrient can be substituted.

    3. which are directly involved in the nutrition of the plant itself.

    One way to understand the differences in deficiency or toxicity of plants is knowing the function of each nutrient inside of the plant. The following is a list of the four nutrients we will use and their known effect on plants.

    • Magnesium: is responsible for the uptake of the nutrients and acts as a carrier of phosphorous in the plant. It is a key element in the molecule of chlorophyll. Deficiencies usually cause a light yellow or white appearance between the parallel veins.

    • Calcium: is needed in the plant to promote early root formation and is responsible for the cementing material between cells of the plant for growth. With calcium deficiencies, leaves have a wrinkled or crinkled appearance, and in some instances, young leaves may never unfold. Roots are short and very bunched.

    • Nitrogen: is responsible for plant protein and promotes the growth of the plant leaf and/or top foliage.

    • Iron: is vital in the formation of chlorophyll and works in the respiratory enzymes. Iron serves to transfer energy in the plant. Deficiency is first exhibited in young leaves by spots lacking green pigment (chlorosis) and will continue to spread over the whole leaf until it turns white. New growth will stop and leaves will die.


    General Guidelines for Laboratory Safety:

    • Students should always wear safety goggles.

    • When handling chemicals and/or seedlings, students should wear disposable gloves. Using gloves to handle the seedlings prevents contamination. Ask your school nurse how to properly remove contaminated gloves.

    • Do not taste any substance.

    • Materials should be disposed of in the following way:

      • All materials used to measure the chemicals should be thoroughly washed in a separate basin with warm, soapy water. Thoroughly dilute the wash water before pouring down the drain.

      • Used gloves should be rinsed in the separate basin before disposing.

      • When disposing of the nutrient mixtures, thoroughly dilute before pouring down the drain.


    Notes for the Teacher:

    • The teacher should consult the Material Safety Data Sheets found on the following websites for guidelines and safety data for the chemicals being used. Any additional chemicals used by teacher choice should be researched for safety by consulting the Material Safety Data Sheets.

      Ferric Chloride:


    Activity #1: Germination of Seeds


    Students will observe the process of seed germination.


    Upon completion of this activity, the students will have several seedlings with which to work.


    Students will work cooperatively within groups of three or four.

    Materials per Group:

    • Six sunflower seeds (presoak seeds one day prior to this activity)*
    • Plastic sandwich bag
    • Moist paper towel
    • Ruler

    *Radish and lettuce seeds (do not presoak; these germinate very quickly) work very well, however, they are much smaller and may cause difficulty for students at the lower elementary levels or for those with fine motor difficulty. These types of seeds may be offered as an option for individual students who may wish to try working with them.

    Teacher Preparation:

    1. Make one copy of Germination Log sheet per child.

    2. Soak seeds in warm water one day prior to this activity.

    3. Prepare vocabulary sheet.
      Germination Log  (PDF, 13K)  Get Acrobat Reader


    1. Fold, dampen, and place the paper towel in the plastic bag. Be sure to remove excess water from the towel.

    2. Place the sunflower seeds on top of the towel.

    3. Smooth and close the bag. Place in a sunny spot.

    4. Make observations and record daily for seven days.

    Optional activity:

    Remove a seedling in order to examine the individual parts of the seedling.


    Activity #2: Teacher Preparation of Nutrient Solutions
    (May be done as a teacher demo)


    • Calcium nitrate
    • Potassium phosphate
    • Ferric Chloride
    • Magnesium sulphate heptahydrate
    • Scale to measure chemicals
    • Wax paper
    • Small scoop
    • Jars with screwtop lids
    • Water (Distilled, if possible). Tap water contains trace amounts of magnesium and calcium. If using tap water, consider filtering it using a piece of cheesecloth or an unbleached filter. Another option is to let the tap water sit out for three days, allowing the chlorine to evaporate.

    Teacher Preparation:

    Prepare solutions according to the chart. All solutions should equal 200 grams.

    Mineral Amount of Mineral Volume of Water
    Calcium Nitrate 22 grams 178 mL
    Potassium Phosphate 27 grams 173 mL
    Ferric Chloride 6 grams 144 mL
    Magnesium Sulfate 49 grams 151 mL


    • Measure each chemical.

    • Place the amount of water needed into the jar.

    • Pour the chemical into the water.

    • Screw the lid on tightly and shake.

    • Label the jar.


    Activity #3: Preparation of the Growth Vessels
    (To be completed the day before planting; approximate time-30 minutes.)

    Materials per Group:

    • Styrofoam meat trays (unused and obtainable from the local butcher). Styrofoam paper plates are a good alternative.
    • Hole punch
    • Scissors
    • Seven jars or clear plastic drinking cups


    Have each of the seven cooperative groups prepare one vessel:

    1. Trace the top of the jar or cup on the meat tray.

    2. Cut out the circle.

    3. Punch two holes on opposite sides of the circle. Be sure to make each hole as far as possible from the edge the edge of the circle.

    4. Cut one slit from the edge of the circle to the hole.


    Activity #4: Preparation of Plant Solutions and Their Addition to Vessels


    Students will prepare growth vessels for fertilizer experiment


    Students will practice measuring liquids

    Materials per group:

    • One prepared growth vessel
    • Germinated seed packet
    • One of the seven solutions
    • Water (Distilled, if possible).
      Tap water contains trace amounts of magnesium and calcium. If using tap water, consider filtering it using a piece of cheesecloth or an unbleached filter. Another option is to let the tap water sit out for three days, allowing the chlorine to evaporate.
    • Commercial liquid plant fertilizer
    • Measuring cups and spoons
    • Labels for jars

    Teacher Preparation:

    Teacher will need to prepare liquid concentrations of chemicals for student use. Preparation may be done as a teacher demonstration. See Activity Two.


    1. Assign one preparation per group.

    2. Label jar appropriately

    3. Mix solutions for experiment according to the following chart:
    Chemical Volume of Stock Solution Volume of Water
    Water   5 1/4 cups
    Liquid Fertilizer five drops 5 1/4 cups
    Calcium Nitrate 2 teaspoons 5 1/4 minus 2 tsp.
    Magnesium Sulfate 1 teaspoon 5 1/4 minus 1 tsp.
    Potassium Phosphate 1/2 teaspoon 5 1/4 minus 1/2 tsp.
    Ferric Chloride 1/2 teaspoon 5 1/4 minus 1/2 tsp.
    All four nutrients 2 tsp. calcium nitrate
    1 tsp. magnesium sulfate
    1/2 tsp. potassium phosphate
    1/2 tsp. ferric chloride
    5 1/4 minus 4 tsp.

    Optional Nutrient Solutions:

    1. "Poor Teacher Solution":
      • 1 tablespoon 5-10-5 standard plant fertilizer
      • 1 teaspoon Epsom salts (substitute for magnesium sulfate)
      • 1 teaspoon washing ammonia

    2. "Local Market Solution":
      • 1 teaspoon baking soda
      • 1 teaspoon Epsom salts
      • 1 tablespoon saltpeter
      • 1 tablespoon washing ammonia

    Mix either one of these solutions with one gallon of water

    Adapted from Botany: Forty-Nine Science Fair Projects

    Solutions should be stored in jars with screw tops and clearly labeled.


    Activity #5: Measuring Seedlings and "Plant"


    Students will observe the growth process of seedlings with different concentrations of fertilizer solutions.


    Students will:

    • measure and record plant growth over a two-week time period

    • organize plant growth data in a useful manner.

    • explain the influence of fertilizer ingredients on plant growth.

    • interpret data on plant growth charts


    Same as Activity One

    Materials per Group:

    • Three sunflower seedlings (See Activity One)
    • One hydroponic growth vessel (See Activity Three)
    • Liquid fertilizer
    • Water
    • Permanent Marker
    • Chemical Solutions (See Activity Four)
    • Plant support system-see step #5
    • aluminum foil

    Teacher Preparation:

    1. Make one copy of Growth Graph per child and one large graph chart for classroom recording.

    2. Assign one of the seven growth vehicles to each group for growth and study.
      Growth Graph  (PDF, 31K)  Get Acrobat Reader


    1. Fill growth vessel to 3/4 full with assigned solution. Use a permanent marker to mark the liquid line.

    2. Use masking tape to label the vessel with the name of the solution, group #, and date.

    3. Remove each seedling very carefully from the plastic bag, being careful not to destroy the roots. Measure each seedling from the point where growth begins to the tip of the root. Record this information on the growth chart and graph.

    4. Before "planting" the seedlings, decide on a method of support for them. Support the plant in one of several ways:

      • Gently wrap a small piece of plain paper towel (about 1"x 3") around the plant, keeping the towel in place by inserting it in the same hole as the plant.

      • Snip a straw into very small pieces, insert a piece of straw into the hole in the styrofoam, and then place the plant in the straw.

      • Place a small amount of clay around the plant where it meets the hole in the styrofoam.

      Be careful that whatever material you use for support does not absorb water and/or any of the nutrient solution.

    5. Place plants into hydroponic vessel, making sure that most of the root system of each plant is sitting in the fertilizer solution. This allows the plant to breathe "Plant" the seedlings by carefully separating the slit in the styrofoam and insert the plant into the circle cut out of the styrofoam. Insert the plant so the paper towel (see step 4) fills the hole and keeps the plant from touching the styrofoam.

      Wrap the vessels with aluminum foil in order to prevent the plants from acquiring mold and algae, and place the growth vessels in a warm, sunny spot.

    6. Have students predict what will happen to their seedlings in their growing solution and record their predictions on their growth observation chart.

    7. Have students record/draw their observations at least twice a week.

    8. Every few days have students check the water level. Add more solution if necessary. As the plants grow, the styrofoam tops may become top heavy and will need to be taped to the jar.

    9. Use the plant heights recorded to construct a bar graph showing the effects the various fertilizer components have on plant growth.

    10. After class discussion and recording of all information, each student should complete a compare/contrast illustration using their group's plant and the control. A narrative explanation should be included.

    11. Assemble these illustrations and narratives into "Plant Investigator's Notebooks." Take one illustration and narrative from every group to make the books so that each book has a page representing all seven growth vessels. Individual groups would then have the opportunity to design a cover for one of the books.

    *If some students have chosen to work with radish or lettuce seeds, insert a very small section of a straw into the holes of the styrofoam tops. This will enable the radish or lettuce seedling to support itself in the growth vessel.

    General Results:

    These are the results after a one week period.

    Commercial Fertilizer 16 cm 11 cm long and clustered
    Water 9.5 cm 8 cm long
    Magnesium Sulfate 4.5 cm 3 cm short
    Potassium Phosphate 3.5 cm 3 cm short
    Calcium Nitrate 10.5 cm 7.5 cm long
    Ferric Chloride 8 cm Dead long
    4-Chemical Mix 11 cm 11 cm long

    Record Keeping Suggestions:

    In addition to the charts provided, try some of these other recording devices.

    1. Observation Journal — To be used for documenting investigations. Structure the entries by having students divide each page, using one half for observations drawings, and measurement, and the other half for thoughts and questions prompted by their observations.

    2. Data Table — This is a titled chart that includes control and the manipulated variables (in this case, the minerals added.) in the left hand column and the responding variable (the height of the plant) in the next column. This information can then be transferred to either a bar or line graph enabling students to see growth patterns. The graphs can be used to show how minerals influence plant height.

    3. Sunflower Class Diary — Have students create either individual sunflowers or a large class bulletin board sunflower.

      • Use a small paper plate as the center of the sunflower and fill it with sunflower seeds or color appropriately.

      • Cut out a flower stem and several leaves. Attach these to the flower center and fasten the flower to a sheet of background paper.

      • Using yellow paper, make a supply of sunflower petals.

      • Each day or every other day, have students date a petal and record the measurement and observation data for that day, i.e. (Sept. 30, our plant measured 3 3/4 inches and has two leaves that are light green).

      • Display the sunflowers in a place where all students will be able to observe them in order to compare/contrast the growth of the various nutrient mixes.

    Discussion Questions:

    During and after the two-week period, stimulate discussion using some of the following questions:

    • Discuss the experiment's control (the water). How did its growth compare with that of the fertilizer and fertilizer components?

    • Did your group's plant grow the same amount between measurements?

    • When did you see the largest amount of growth? the smallest?

    • If your plant grew in spurts, can you explain why?

    • What does the graph tell us?

    • Which group's plant grew the most in one week? two weeks?

    • What happened to each individual plant?

    • In each individual case, why do you think the plant demonstrated the type of growth that it did?

    • What can we conclude from these observations?


    Extension Activities

    Activity #1: Tracking Liquid in Leaves


    To see the path water takes as it travels through a leaf.


    • Two plastic cups or jars
    • Tap water
    • Food coloring
    • Scissors
    • Two fresh leaves


    1. Fill two cups 1/4 full of water.

    2. Add enough food coloring to the water in one cup to make the water a deep color.

    3. Cut off the ends of the leaves' stems and stand one leaf, stem down, in each glass of water.

    4. Observe the leaves for three days. As the colored water moves slowly through the first leaf's veins, the color should expand out to the rest of the leaf, thus changing the color of the leaf.


    Activity #2: How Do Plants Eat Nutrients?


    To explore how and why water travels through plants


    • two plastic cups or jars
    • water
    • food coloring
    • two celery stalks with leaves
    • magnifying lens


    1. Fill glasses 1/4 full of water.

    2. Add enough food coloring to one cup to make the water a deep color.

    3. Cut off the ends of the celery stalks and stand one stem in each glass.

    4. On the fourth day remove the stalks from the glasses and dry them with a paper towel.

    5. Study the leaves of the stalks. The stalk from the colored water should have colored leaves. The leaves of the other stalk should still be green.

    6. Use a plastic knife to chop the stalks into one-inch pieces.

    7. Using the magnifying lens, study the outer surface of each celery piece, including the freshly cut surfaces. Colored stripes and dots should be visible on the cut surfaces.

    *This procedure can also be completed using a white carnation.


    Activity #3: Using Root Vegetables

    • Rather than using seeds, place potatoes or onions in jars and allow them to root in a dark place.

    • After rooting, add nutrients and observe growth pattern. Be sure to keep a set of potatoes or onions in water only.

    You may wish to plant some of the vegetables in various types of soil in order to compare/contrast the effect of hydroponically grown vegetables. Add nutrients to these plants as well.

    This activity was adapted from, "Hydroponics-Space Technology: Benefiting Mankind."


    Activity #4: Environmental Factors


    To understand the role environmental factors, such as climate (heat, cold, dry, wet) and types of soil and its nutrients have on plants.


    1. Alter growing conditions of plants.

    2. Grow three plants in soil:

      • Give one on plant food

      • Give another commercial food

      • Use compost material for the third

      Observe and compare the plants' growth.

    3. Grow three plants in soil:

      • Place one in a dark spot removed from sunlight for several days

      • Skip regular watering for another plant

      • Give the third one proper plant care.

      Have students observe, and when a plant begins to fail, resume proper treatment to attempt to revive its growth.



    • adaptation — an activity that assists a living thing to survive.

    • balance — a measuring tool

    • chlorophyll — the green photosynthetic matter of plants

    • crust — an outer layer of rock that covers the whole earth

    • fertilizer — all purpose fertilizers are balanced blends of nitrogen, phosphorous and potassium, which are necessary plant nutrients

    • foliage — the leaves or the green part of the plant

    • growth medium — the material that holds the nutrient solutions and supports the roots of the plant

    • hydroponics — a system for growing plants without using soil

    • leaf/leaves — green plant structures that grow from the stem, and the parts of a plant that are used to gather the sun's energy

    • leggy — unusually tall, with sparse foliage

    • nutrients — food or chemical substances necessary for growth

    • photosynthesis — the process by which plants build chemical compounds from light, energy, water, and carbon dioxide

    • producer — a name give to green plants because they are able to make their own food

    • root — the part of the plant that absorbs moisture and nutrients. Roots stabilize the plant and keep it from being blown or washed away

    • seed — something that grows into a plant

    • seedling/sprout — a young plant grown from a seed

    • stem — the part of the plant that grows out of the seed. Leaves grow out of the stem


    Student Resources

    Benny Broccoli and His Buddies
        American Crop Protection Association
        Suite 400
        1156 Fifteenth St., NW
        Washington, D. C. 20005
    This is a pamphlet that promotes interest in agriculture.

    Carle, Eric. The Tiny Seed. Simon & Schuster, 1987.

    Cole, Johanna. The Magic School Bus Plants Seeds. Scholastic, Inc., 1995.

    ______. The Magic School Bus Gets Planted. Scholastic, Inc., 1997.

    King, Elizabeth. Backyard Sunflower. New York: Dutton, 1993.
    Photos and text tell the story of a sunflower garden.

    Stewart, Sarah. The Gardener. Trumpet, 1997.


    Teacher Resources

    Bleifeld, Maurice. Botany Projects for Young Scientists. Franklin Watts, 1992.

    Hixson, B. K. Science Without Answers. Wild Goose Company, 1989.

    ______. Desktop Science. Wild Goose Company, 1994.

    Molleson, Diane & Swooge, Sarah. Easy Science Experiments. Scholastic, 1993.

    Suzuki, David. Looking at Plants. John Wiley & Sons, Inc., 1991.

    Hydroponic Society of America:
        P. O. Box 3075
        2819 Crow Canyon Road
        Suite 218
        San Ramon, CA 994583
        510-743-9302 (fax)

    Homegrown Hydroponics:

    "The Land-Hydroponic Grow Tank."
    Walt Disney World Company
    P. O. Box 10000
    Lake Buena Vista, Florida 32830-1000

    Stewart, Martha. Living: Sunflowers, September, 1995.



    Ardley, Neil. The Science Book of Things That Grow. 1991.

    Bonet, Robert L. & G. Daniel Keen. Botany: Forty-Nine Science Fair Projects. Tab Books, 1989.

    Greentree Hydroponics

    Hands on Science: Seeds to Plant. Aladdin Books, 1990.

    Machlis, Leonard & John G. Terry. Plants in Action: A Laboratory Manual of Plant Physiology. W. H. Freeman and Company, 1956.

    National Academy Press/National Academy of Sciences:

    Schaffer, Frank. Schooldays, April/May, 1993.

    Silver Burdett & Ginn Science Level 4, pgs. 24-45, 1989.

    "Space Technology: Benefiting Mankind." Young Astronaut Council, October-December, 1993.

    Wonder Science, Vol. 13, #3, Fall, 1998. "Let's Graph It." American Chemical Society, Washington, D. C.

    This experiment is courtesy of 

    My Dog Kelly

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    Last updated: January 2011
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