Pre-Activity 0.2GL: Plant Growth Investigation Setup (45 min over 1 or 2 days)

Target Student Performance

Students plant radish seeds, record initial masses, and let seeds grow for at least 4 weeks. After four weeks, the plants will be large enough to begin the rest of the Plants Unit.

There are two different versions of this Pre-Activity to choose from depending on the depth of instruction you’d like to cover. Please refer to the Background Section at the beginning of this lesson plan for more information about each.

Gel Protocol (2-turtle)

    • Pre-Activity 0.1GL: Keeping Track of Water in Solids and Liquids (60 min + overnight or several days)
    • Pre-Activity 0.2GL: Plant Growth Investigation Setup (45-60 min over one or two days)

Paper Towel Protocol (1-turtle)

    • Pre-Activity 0.2PT: Plants Growth Investigation Setup (45-60 min)

Pre-Activity 0.2GL: Plant Growth Investigation Setup (45 min over 1 or 2 days)

This Pre-Lesson Activity is part of the Gel Protocol (2-turtle) and should only be taught if you have chosen this pathway (see Background Information for details).

Resources You Provide

  • Large (37mL) test tubes or other clear receptacle (1 per student)
  • 1 packet of gel crystals (hydrated already if completed pre-lesson 1.1) (1 per class)
  • 4 teaspoons of Ionic Grow (1 per class – not necessary if completed pre 1.1)
  • Gallon of distilled water (1 per class – not necessary if completed pre 1.1)
  • Bucket or bowl (>1 gallon) to hydrate gel overnight (1 per class – not necessary if completed pre 1.1)
  • Strainer/colander large enough for hydrated gel (1 per class- not necessary if completed pre 1.1)
  • Digital scale (to 0.1g) (1 per group)
  • Grow/Fluorescent Light
  • Test tube rack
  • Permanent markers and labels for test tubes
  • Fresh packets of radish seeds (at least one seed per student or group plus a few more)
  • Squeeze bottle to water plants

Resources Provided


  • For the gel crystals, 1 gram (~1/4 tsp) of crystals absorbs ~70g of water. Only ~0.25g of dry mass goes in to each 37 mL test tube. 1 packet (~17g) makes enough gel to fill ~ 60 37mL test tubes.
  • Look for 20 X 150mm Pyrex glass test tubes, 37 mL capacity. If those are not available, clear plastic vials or small cups can work.
  • You will make the nutrient mixture with 4 teaspoons of Ionic Grow to 1 gallon distilled water during class with students (unless you already completed pre 1.1)
  • Things inevitably go wrong when growing plants. Be sure to plant some extras. At least one extra radish plant per group of students is recommended.
  • The squeeze bottle (e.g. ketchup bottles work well) is for future maintenance of plants.
  • Print one copy of the Pre-Lesson 0.2GL Plant Growth Investigation Setup Worksheet for each student.
  • Prepare your computer, projector, and speakers for the Growing Plants Investigation Video and the Pre-Lesson 0.2GL Plant Growth Investigation Setup PPT.


1. Use the instructional model to show students where they are in the course of the unit.


There is no assessment for this activity since students are setting up an experiment to learn from later on.


  • If many of your students seem convinced that plants will not grow without soil nutrients, you may want to rehydrate a few gel crystals with water only to see if the radish seeds will germinate and start to grow (they should!).
  • Allow students to take pictures of what they are putting into their test tubes as a reference for later on after plant growth.


You can increase or decrease the level of complexity of the math problems students need to do here in order to calculate initial dry mass. For instance, students can weigh the radish seed, discover it weighs less than 0.01 grams, and record that as the mass, as it is essentially negligible. Or, students could weigh multiple radish seeds and calculate the average mass for each seed (recommended). Similar types of math problems could be done with the gel and nutrient mixture.

Extending the Learning

Have students make regular observations of their seeds as they grow over the next 3-4 weeks.