1 COMPANION PLANTING WITH SYMBIOSIS AND SYSTEMS TIP: If there is more time available, consider adding a Station D with a graph or chart for students to interpret (it can be a graph of plant growth over time in close proximity to and further away from a potential companion plant). DESCRIPTION: Students explore a garden to find symbiotic relationships and think about the functions that plants can provide. Students practice companion planting to predict the outcome of an experiment and troubleshoot problems with designing a garden when plants can be either beneficial or harmful to one another. BACKGROUND INFORMATION: When two living organisms, such as plants, live together, it is called symbiosis. The focus in this activity is about companion planting, which is really the study of beneficial symbiotic relationships among plants. There are many ways plants affect each other. Here are a few: Better Growth: Some plants simply grow better around certain plants, and not as well with others. No one yet knows the exact science of why. Example: Green beans grow well with strawberries. Bibb lettuce grows well with spinach. Nutrition: In the plant world, there are heavy feeders and heavy givers. Heavy feeders are plants that take and keep a lot of nutrients from the soil as they grow. A lot of the plants we love to eat (tomatoes, lettuce, corn, squash to name a few) are heavy feeders. Heavy givers, on the other hand, are plants that give back a lot of nutrients to the soil. Nitrogen-fixers or legumes, are examples of heavy givers: peas, beans, alfalfa, clover, and vetch. After growing heavy feeders in a particular area, it s a good practice to plant heavy givers to restore the soil. Accumulators: Many wild plants including those we consider weeds play a vital role in the plant community as doctors and healers of soil. Many weeds either collect trace minerals from the soil for future fertilization or remove harmful elements from the soil. Example: pigweed, lamb s quarters, and thistles have deep roots to bring up minerals from the lower soil, which they hold in their stalks and leaves. When they die and decompose into the topsoil, these minerals become available to crops with shallower roots. Pest Control: Some plants give off chemicals from their roots or leaves. Example: certain kinds of marigolds give off a chemical from their roots that are absorbed by plants around them. When whiteflies come to suck on the leaves of those plants, they think they are eating the bad-tasting marigolds and they leave. Physical: Many plants have a special need for sunlight or shade. One plant can help provide these conditions for another. Example: Lettuce plants like to nestle among other taller plants for shade. Pollinator Attractors: Many plants reproduce with the help of beneficial insects and other pollinators. By putting plants that pollinators love in your garden, you will help the other plants as well! Example: Bees love hyssop, thyme, catnip, and lemon balm. Once you bring bees to the garden, they will help pollinate everything.
2 PAGE 02 Types of Symbiotic Relationships: Mutualism is a mutually beneficial relationship in which both organisms benefit. Each individual provides an advantage to the other, enabling them to exploit each other and thereby enhance their chances of survival. Example: Corn and beans The corn provides a tall structure for the beans to climb and the beans pull nitrogen from the air and bring it to the soil for the benefit of both of them. Commensalism is loosely defined as a symbiotic relationship in which one organism benefits and the other is unaffected. Example: Sage plants produce an odor that repels carrot-flies. If planted by carrots, the carrots benefit while the sage plants are unaffected. Parasitism is a relationship that is beneficial for one organism and harmful for the other. Example: The mistletoe, a plant that parasitizes trees, has roots that penetrate the tree bark, capturing nutrients from the tree, but damaging the tree s own protective layer. OBJECTIVES: Students discover which plants have symbiotic relationships and how this impacts each organism. They identify three general types of symbiosis: mutualism, commensalism, and parasitism. Students see the interconnectivity between different plants and animals and their environments. Many relationships between organisms are complex and involve multidirectional interaction. COMMON CORE STANDARDS: CCSS: 7.W 4: Produce clear and coherent writing 7.SL 1: Engage effectively in a range of collaborative discussions with diverse partners NGSCS: LS1.A: Cells work together to form tissues and organs with a function LS2.A: Organisms and POPs are dependent on their environment. Interactions with biotic and abiotic things. LS2.A: Mutualism, Commensalism, Parasitism PS2.C: Patterns of change and an understanding of feedback mechanisms are used to predict a system s future NGSCS Cross-Cutting Concepts: 1. Patterns: Macroscopic patterns are related to the nature of microscopic and atomic-level structure. 4. Systems and System Models: Models can be used to represent systems and their interactionssuch as inputs, processes and outputs- and energy, matter, and information flows within systems TIME: 50 MINUTES. THINK-PAIR-SHARE (5 MINUTES); 10 MINUTES PER STATION (3 STATIONS); 15 MINUTE DISCUSSION
3 PAGE 03 MATERIALS: 1 clipboard or field notebook per student 1 copy of Companion Planting Guide per group 1 Station Packet per student (includes the directions for stations A-C) Enough table space outside for groups to gather PREP: Within a garden, plant one set of companion plants close to one another and another set farther away from each other on the same day (carrots and leeks are great for fall; other examples can be found in the Companion Planting Guide). Hopefully, when brought together, the plants are growing visibly healthier or bigger than the other plants which are separated. Have four stations prepared outdoors by the school garden. For student comfort and efficiency, the area should have some shade for hot days and a tabletop bench for writing. Each station should have printed titles and directions. Provide each student with worksheets. Label the companion plants with the plants names. Label the Station B Experiment visibly so that the students can find the Station B Experiment. ACTIVITY: 1. Start with a Think-Pair-Share activity.»» Ask students to individually think about the following question: What are some examples of symbiosis in the animal world? (one minute).»» Have students form groups of four to have them discuss their thoughts with the other students.»» Now discuss as a class (up to five minutes). 2. Assign groups to a station A-C and have them rotate every 10 minutes. 3. As the students explore the garden, use Exploration Questions provided in the Appendix to guide them. 4. After rotating the students through the stations, return to the classroom. DISCUSSION: 1. The class can share their garden bed designs. 2. Students can discuss the possible functions of plants (see the Companion Plant Guide for possible answers). TEACHER TIPS: To simplify this exercise, ask your student to work in pairs.
4 PAGE 04 VEGETABLE COMPANION PLANTING GUIDE VEGETABLE COMPANION ANTAGONIST Asparagus Beans Bush Beans Pole Beans tomatoes, parsley, basil potatoes, carrots, cucumbers, cauliflower, cabbage, summer savory, most other vegetables and herbs potatoes, cucumbers, corn, strawberries, celery, summer savory corn, summer savory onions, garlic, gladiolus onions Beets onions, kohlrabi pole beans Cabbage Family (cabbage, cauliflower, kale, kohlrabi, broccoli) Carrots Celery aromatic plants, potatoes, celery, dill, chamomile, sage, peppermint, rosemary, beets, onions peas, leaf lettuce, chives, onions, leeks, rosemary, sage, tomatoes leeks, tomatoes, bush beans, cauliflower, cabbage onions, beets, kohlrabi, sunflowers strawberries, tomatoes, pole beans Chives carrots peas, beans Corn beans and squash, potatoes, peas, cucumbers, pumpkins Cucumbers beans, corn, peas, radishes, sunflowers potatoes, aromatic herbs Eggplant Leeks Lettuce Onions (and Garlic) Parsley Peas Potatoes beans onions, celery, carrots carrots, radishes (lettuce, carrots, and radishes make a strong team together), strawberries, cucumbers beets, strawberries, tomatoes, lettuce, summer savory, chamomile (sparsely) tomatoes, asparagus carrots, turnips, radishes, cucumbers, corn, beans, most vegetables and herbs beans, corn, cabbage, horseradish (should be planted at corners), marigold, eggplant (as a lure for Colorado potato beetle) dill peas, beans Pumpkins corn potatoes Radishes Soybeans Spinach Squash Peas, nasturtium, lettuce, cucumbers Grows with everything, helps everything. Strawberries Nasturtiums and corn Strawberries Bush Beans, spinach, borage, lettuce (as a border) Cabbage Sunflowers Cucumbers Potatoes Tomatoes Turnips Chives, onions, parsley, asparagus, marigolds, nasturtiums, carrots Peas onions, garlic, gladiolus, potatoes pumpkins, squash, cucumbers, sunflowers, tomatoes, raspberries kohlrabi, potatoes, fennel, cabbage
5 PAGE 05 KEY Possible Functions of Plants (Discussion and Station A): cool down environment fix nitrogen restore soil pull nutrients from deep soil to topsoil break up clay soil medicine repel pests building materials for us and other animals (like birds nests) to be eaten attract animals insects birds lizards snakes prevent invasion by weeds generate mulch naturally or when trimmed down to prevent erosion to purify water to screen an unwanted view to block wind provide shade slow a fire
6 PAGE 06 STATION WORKSHEETS/INSTRUCTIONS STATION A Open-Ended Investigation Examine the plants in the garden. Using only this area, investigate to learn as much as you can about: 1. What sorts of relationships can you see among the plants in the garden? (Use the words mutualism, commensalism, parasitism) 2. What does a plant needs as inputs? 3. List the different functions or products that plants can provide: STATION B Structured Activity Follow the procedures described on the worksheet provided. 1. Find two plants labeled & 2. If you were to plant these plants closer together, do you predict either plant to grow better, worse, or the same? Why? 3. Find the pre-planted experiment labeled as (Station B Experiment) in the garden. Observe and describe the results you see. Which kind of symbiotic relationship are they displaying? Note that both of these plants were planted on the same day as the plants you list in step Do you have any explanation to match your evidence?
7 PAGE 07 STATION C Problem-Solving Challenge There are many seeds to choose from to plant but only so much space in the garden beds! Some like shade, some like sun, etc. Design a garden bed that minimizes parasitic relationships between plants within this small space. Choose 5 varieties of seeds from the list below: Herbs: anise, arugula, borage, chervil, chamomile, chives, cilantro, dill, fennel, feverfew, garlic chives, lavender, lemon grass, lovage, parsley, rosemary, salad burnet, sorrel, tansy Vegetables: beets, broccoli, brussel sprouts, cabbage, carrots, cauliflower, celery, collards, fava beans, kale, kohlrabi, leeks, lettuce, mustard, parsnip, peas, radish, rutabega, swiss chard, turnips List your 5 choices here: Know Your Companions...and your antagonists. Check your 5 choices on the Companion Planting Guide. Are there any that like each other a lot or any that should not be planted near each other? Write those below: VEGETABLE KNOWN COMPANIONS KNOWN ANTAGONISTS Map your symbiotic garden within the rectangle!