Project - Raising Plants
To study the life cycle and structure of plants, students grow plants from seed, fertilize them, and collect seed, starting the process over again. With the right growing conditions, almost ...
To study the life cycle and structure of plants, students grow plants from seed, fertilize them, and collect seed, starting the process over again. With the right growing conditions, almost any plant can be grown successfully in the classroom – native plants for a restoration project, vegetables, cut flowers, etc. The instructions provided here are for growing Wisconsin Fast Plants since they are the most widely used species in classrooms across America. These plants have been artificially selected to grow well in small spaces, with indoor lighting, with little soil, and with an exceedingly short life cycle (14-20 days to flower and 21-40 days to set seed). Therefore, they are incredibly well adapted to survive in classroom conditions as well as participate in multi-generational studies such as plant life cycle studies, Mendelian crosses and artificial trait selection. However, the light boxes and terraqua columns lend themselves to growing virtually any
Can observe and document the stages of a flowering plant’s life cycle from seed to flower to seed.
Brassia rapa (Wisconsin Fast Plants)
Radicle (embryonic root)
Hypocotyl (early stem)
Cotyledons (early leaves)
Raising Plants - Logistics
40-50 min to build a light box
20 min to build terraqua columns (See Terraqua Columns activity for details)
20 min to plant seeds
5-10 min to build bee sticks
5-10 min to fertilize on day 14-20
5-10 min to harvest seeds on days 21-40
Time to conduct experiments and make observations varies.
Each light box fits up to 9 terraqua columns constructed from 500 ml water bottles. Each water bottle terraqua column can accommodate 4 mature Fast Plants. Determine the grouping size based on the experiment you plan to try. Calculate the number of terraqua columns and light boxes required.
For one light box you need:
- Box cutter
- 1 banker box or copy paper box
- 1 Lights of America™ 30 watt CircleLite (order from Energy Federation Incorporated part # 1140.05 for $9.95 each)
- 1 single socket electrical cord (available at most hardware stores for $5-10, often used for paper lanterns, garage utility lights, or lamp-making kits)
- Tin foil
- Clear scotch tape
- Optional: window screen material and duct tape (bugs may be attracted to your light box and the screens can help keep the bugs out)
Don’t want to build light boxes? Have money to spare? Order one ready-made! Carolina Biological has several options:
- Plant Light House™ (catalog # 15-8994, one light box for $85) is similar to the one described in this lesson
- Plant Light Bank™ (catalog # 15-8998, one light bank for $145) is a table-top version with long fluorescent bulbs.
For 30 terraqua columns you need:
- Seeds (A wide variety of Wisconsin fast plant seeds may be purchased from Carolina Biological. Standard seeds are catalog #15-8804 and 15-8805, 50 seeds for $10 or 200 seeds for $24)
- 30 clear plastic water bottles (500 ml)
- 30 6-inch long wicks (use a strip of cotton towel or a string from a janitor’s mop)
- Soil. Fast plants grow best in medium or coarse vermiculite (Vermiculite is a mica-like mineral that expands in an accordion-like fashion in water, and is thus used as a soil additive for water-retention. You can find it in most garden centers for around $5-8 for an 8 quart bag.)
- N-P-K fertilizer. Required for fast plants but may be unnecessary for other species.
Don’t want to build terraqua columns? Have money to spare? Order growing systems ready-made! Carolina Biological has several options:
- Seed Challenge: Exploring Life Cycles Kit (catalog #15-8973, $60) provides everything needed for a class of 32 to raise Wisconsin fast plants from seed to seed - including a curriculum guide - except the light box (there are kits available for many other standard experiments as well, including monohybrid crosses, dihybird crosses, butterfly-flower interactions and more)
- Growing System (catalog #15-8993, $35) provides everything for a class of 32 students except seeds and the light box
- Watering System (catalog #15-8974, one watering system for $9.25) is designed for use with Quads (catalog #15-8960, 16 quads for $6.70) these are the watering system developed by Carolina Biological specifically for Wisconsin fast plants. Each quad holds 4 plants and each watering system holds 8 quads.
Bee sticks (for pollinating your plants)
For 30 bee sticks you need:
- Dried bees (Carolina Biological catalog #15-8985, $5 for around 70 bees)
- Elmer’s glue
Raising Plants - Background
Wisconsin Fast Plants (Brassica rapa) are an extraordinary resource for teachers since they have been selected for over 30 years for traits that make them ideal model organisms for the classroom. They thrive under fluorescent lighting, need very little soil, complete their life cycle in about a month, and take up very little space. Moreover, for under $50, a teacher can set up a classroom greenhouse and growing system for 32 students (2 light boxes and 18 terraqua columns growing 4 plants each).
There are 4 growing requirements for Fast Plants:
- They need fluorescent lighting 24 hours a day. Ideally, the lights should be situated 5-10 cm from the plants. Directions for how to build a light box are provided.
- They need continuous water and fertilizer. The easiest way to accomplish this is to grow the plants in a self-watering terraqua column or growing system with fertilizer added directly to the water reservoir.
- They need consistent room temperature (between 65–78 °F or 18–26 °C). If the temperature goes above 90 °F, the flowers will be sterile. Make sure that the fluorescent lights don’t become hot.
- The roots need the aeration provided by a potting mixture and will not grow well in regular soil. Use coarse or medium grained vermiculite and even better in a 1:1 mixture of vermiculite and peat.
Raising Plants - Getting Ready
- Build your own light box and terraqua column as an example to show the students.
- Collect enough banker boxes or copy paper boxes for your group.
- Create light box building kits with scissors, a box cutter, aluminum foil, glue and scotch tape.
- You may want to print out a copy of the light box building instructions as an overhead or make enough copies for each group to have one.
- See getting ready steps in the Terraqua Column activity for how to set up for terraqua column construction.
Raising Plants - Procedures
To build a light box:
See the light box assembly directions on the Wisconsin Fast Plant website for detailed information.
- Distribute boxes, single socket electrical cords, circular light bulb and light box building kits to each group.
- Have students set their box on the table with one of the small, square ends down. That is now the bottom of the box.
- Use the box cutter to cut a one inch diameter hole in the top of the box. The screw end of the circular light bulb should just squeeze into the hole.
- Use the box cutter to cut long rectangular slits (4x14 cm) in the sides and of the box, near the top edge. These are vents to prevent your plants from overheating.
- Line the inside of the box with aluminum foil. Use glue to glue the foil securely to all sides, and the top and bottom of the box. Make sure you leave the top hole and vent slit open.
- Working from the inside of the box, insert the circular light bulb through the top hole.
- While 1 person holds the light bulb, a second person should screw the light socket onto the light bulb.
- Make an aluminum foil curtain for the front of the box. The curtain should completely cover the opening. Tape the curtain to the top of the box and reinforce the sides if desired with clear tape.
- Optional: Cut pieces of window screen material to cover the vent holes from the outside. Use duct tape to secure them in place.
To build a terraqua column:
See the lesson plan of the Terraqua Column activity for a description of how to build terraqua columns with students.
Day 0 - Plant Wisconsin Fast Plant seeds:
See the planting and fertilizing tips on the Wisconsin Fast Plant website for detailed information.
- Moisten the vermiculite so that it expands and is damp to the touch.
- Saturate the wick in water.
- Mix the fertilizer into the water. Use a 1 part liquid fertilizer to 8 part water mixture or follow the directions for the N-P-K fertilizer you plan to use.
- Insert the wick through the hole in the cap. Screw the cap onto the opening of the bottle.
- Invert the planter onto the reservoir. Make sure that the wick reaches all the way from the bottom of the reservoir to the top of the planter.
- Add water to the reservoir.
- Add moist vermiculite to the planter. When adding the soil, hold the end of the wick up and fill in the vermiculite around the wick. Make sure that the wick is not stuck against the side of the planter. Bury the top of the wick in the vermiculite.
- Drop 8-12 seeds onto the surface of the vermiculite. Seedlings will be thinned later to a maximum of 4 plants per terraqua column.
- Lightly cover the seeds with a thin layer of vermiculite.
- Lightly water the soil.
- Place the system into the light boxes. Place the tops of the terraqua columns 5-10 cm from the lights. Use books to prop them up to the right height.
- Have students make initial observations of their terraqua columns, noting the number of seeds planted.
Day 4-5 – Thin seedlings
By now, seedlings should have pushed through the surface of the soil. Thin your seedlings so that there are no more than 4 seedlings per terraqua column or 1 seedling per cell in a quad. Try to leave seedlings that are spaced reasonably far apart.
Days 5-14 – Maintain your plants and make observations
By now, your plants should be growing well. Make sure the water reservoirs are full of nutrient rich water (especially before the weekend). Make sure the lights are 5-10 cm away from the plants (use books to prop them up). Make observations of your plants as they grow. Some traits that are easily measured:
- Number of days to germinate
- Ratio of seeds germinated to seeds planted
- Plant height
- Number of days to first leaf
- Number of leaves
- Number of hairs on leaf margins
- Leaf color
- Stem color
- Number of days to first flower bud
- Number of flower buds
- Water usage
- Number of seed pods
- Pod length
- Number of days to seed pod maturity (tips of pods will turn brown)
- Total number of seeds collected per plant or per pod
Before day 14 – Make bee sticks
- Distribute one dried bee and one toothpick to each student.
- Set out glue.
- Remove the head, legs, and abdomen of the bee, leaving only the round, fuzzy thorax region and the wings if you wish.
- Put a drop of glue on the top of the toothpick. You do not need much glue.
- Insert the glue covered tip into the thorax. You may wish to put the toothpick into one of the holes left when you removed the head or abdomen.
- Set the bee stick aside for the glue to dry.
Day 14-20 – Fertilize flowers
By now, the flowers should have bloomed. Take the bee stick and rub it against the anthers of a blossomed flower. Move to the flowers of a different plant and rub against the pistil. Continue fertilizing until all the flowers in the classroom have been cross-fertilized. See the pollination directions on the Wisconsin Fast Plant website for detailed information.
Day 21-40 – Collect seeds
See the fertilization and seed development directions on the Wisconsin Fast Plant website for detailed information.
- 10-20 days after the last fertilization, some of the pistils will have turned into long seed pods. When the tips of the pods turn from green to brown, the plants are ready to be dried. Remove the water from the bottom reservoir.
- Let plants dry for 7 days. The pods should be brown and crispy.
- Cut the stem of the plant below the bottommost pod and place the whole plant into a labeled paper bag.
- Seal the bag with tape or staples then crush the plant inside, breaking up the pods thoroughly to release the seeds.
- In a shallow tray, pour out the contents of the bag. Pick out the large pieces of stem, leaves and pods.
- The smallest pieces of broken pod can be separated from the seeds by gently blowing across the surface of the tray. The pod pieces will blow away.
- Seeds may be stored in a labeled paper envelope. To store seeds for a year or more, place the envelope in a ziplock bag with silica gel (one of those packets often found with dried foods to absorb moisture).
Raising Plants - Experiment Ideas
See activity ideas on the Wisconsin Fast Plant website for detailed information.
- Life Cycle – Raise Fast Plants from seed to seed. At each stage of the life cycle, discuss and study what the plant is doing. Discuss seeds, germination, growth, flowering, pollination, fruiting, and seed dispersal. Have students draw a life cycle diagram, adding a labeled picture of their plant at each stage of the life cycle. See the Fast Plants Life Cycle activity guide for a great diagram of the life cycle and information about the plants at each stage of life.
- Plant Traits – Examine the variation in plant traits. Pool the observations students made during the growth and flowering phases of the plant life cycle. Examine and graph the population data to determine whether there is a bell curve distribution of traits such as plant height. See the Growth, Development, and Flowering activity guide and the Getting a Handle on Variation activity guide for two different ways to conduct a study of plant traits and variation in a population.
- Artificial Selection - Sponsor an artificial selection program for hairiness (or height) in Fast Plants. Breed Fast Plants over several generations, always selecting either the most hairy or the least hairy plants to cross fertilize. For each generation, carefully quantify the number of hairs on each individual and construct a histogram showing data for the whole population. See the Hairy's Inheritance: Selection, Variation, and Inheritance activity guide for detailed information.
- Ecology – Experiment with environmental variables - salinity of the water, light conditions, nutrient supply, population density, pollution, or other factors – and monitor differences in plant growth and development. See any of the activities under Ecology, Environment, and Interactions Between Abiotic and Biotic Factors for detailed lesson plans.
- Coevolution – Investigate the coevolution of insects and flowering plants. Study the thorax of a bee under a dissecting microscope or strong magnifying glass. Look at the shape of the hairs on the bee’s body and its relationship to pollen. See the Flowering and Pollination - Pollination Biology activity guide for detailed information. Alternatively, raise Fast Plants and butterflies together in the same light box, studying their symbiotic relationship. See Brassica butterfly activities and rearing guide on the Wisconsin Fast Plant website.
Raising Plants - Sources and Standards
For information on Wisconsin Fast Plants, see:
- The Fast Plants website with just about everything you ever wanted to know about Fast Plants including growing tips, activities and more.
- Wisconsin Fast Plants Manual (Carolina Biological catalog #15-8950, $28)
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
a. Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs.
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
1. All living organisms are composed of cells, from just one to many trillions, whose details usually are visible only through a microscope. As a basis for understanding this concept:
f. Students know that as multicellular organisms develop, their cells differentiate.
2. A typical cell of any organism contains genetic instructions that specify its traits. Those traits may be modified by environmental influences. As a basis for understanding this concept:
a. Students know the differences between the life cycles and reproduction methods of sexual and asexual organisms.
3. Biological evolution accounts for the diversity of species developed through gradual processes over many generations. As a basis for understanding this concept:
a. Students know both genetic variation and environmental factors are causes of evolution and diversity of organisms.
Structure and Function in Living Systems
5. The anatomy and physiology of plants and animals illustrate the complementary nature of structure and function. As a basis for understanding this concept:
a. Students know plants and animals have levels of organization for structure and function, including cells, tissues, organs, organ systems, and the whole organism.
b. Students know organ systems function because of the contributions of individual organs, tissues, and cells. The failure of any part can affect the entire system.
f. Students know the structures and processes by which flowering plants generate pollen, ovules, seeds, and fruit.
Investigation and Experimentation
7. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations.