UNIT 9
GLORIOUS GARDENING
BARLEY, RICE, WHEAT, PEAS, AND SQUASH WERE SOME OF THE FIRST CROPS THAT HUMANS CULTIVATED IN ANCIENT FIELDS AND GARDENS. For thousands of years, people have treasured seeds that grow fast, foil pests, and yield tasty food. Long before people started playing with plant DNA in labs, farmers and gardeners were selectively breeding new plant hybrids, cross-pollinating and grafting favorite plant species to perfect their produce.
Today, modern agriculture is experiencing an onslaught of issues. Even with a wealth of science at our fingertips, food safety, crop diversity, and delicate ecosystems are all at risk as we fight to feed an exploding world population. Should an agricultural apocalypse ever befall us, forward thinkers have built seed vaults in places such as the North Pole, sheltering frozen seeds from thousands of plant species.
With water, sunlight, warmth, and nutrient-rich soil, you can grow your own food from seeds. In this chapter, you’ll have a race to see how fast seeds sprout, watch seedlings maneuver toward the light, and compost kitchen scraps to make fertilizer.
LAB 36
ALLELOPATHY EXPERIMENT
SPROUT SEEDS TO LEARN HOW SOME PLANTS USE CHEMICAL WARFARE TO DEFEND THEIR SPACE.
MATERIALS
1 large rectangular planter, or several small flowerpots or cups
Potting soil
Ice pop sticks or wooden garden markers
2 or more of the following: lemons, oranges, black walnuts, pine needles, mint, eucalyptus leaves, chrysanthemum leaves, or tomato plant leaves
Mortar and pestle, food processor, or other tool for grinding nuts
Citrus zester or grater
Chia seeds or radish seeds
SAFTEY TIPS & HINTS
— Black walnuts are tree nuts, so be allergy aware.
PROTOCOL
STEP 1: Fill your planting containers with potting soil.
STEP 2: Subdivide large containers with ice pop sticks, with a section for each substance you want to test, plus one section with no substances, as a control. Label each section with an ice pop stick or garden marker. If using small pots, label one for each substance, plus a control.
STEP 3: Grind nuts, grate citrus peels, and chop or crush leaves to create mixable versions of the substances you want to test, cleaning your tools in between to avoid cross-contamination. (Fig. 1, 2)
Fig. 1: Grind black walnuts or crush leaves.
STEP 4: Mix each of the substances into the top few inches (7 to 10 cm) of the section or pot you have labeled for them. Don’t mix anything into the control section. (Fig. 3)
Fig. 3: Mix substances into the soil.
STEP 5: Plant chia or radish seeds in each section. Make pencil holes to plant the same number of seeds in each section, or put a few teaspoons (13 to 17 g) of seed in each pot or section and mix them evenly into the soil.
STEP 6: Gently water the seeds.
STEP 7: Check the seeds every day. Record when they sprout in each section and which substances appear to have allelopathic effects on seed growth, preventing them from sprouting or growing. (Fig. 4)
Fig. 4: See what substances affect seed growth.
CREATIVE ENRICHMENT
Collect invasive plants such as buckthorn, garlic mustard, spotted knapweed, and nutsedge to test the allelopathic effects of their leaves, seeds, and fruit.
LAB 37
COMPREHENDING COMPOST
DIG A HOLE IN THE DIRT TO LEARN MORE ABOUT THE NUTRIENT CYCLE AND MAKE FERTILIZER FOR YOUR GARDEN.
MATERIALS
Biodegradable kitchen waste such as coffee grounds, fruit and vegetable scraps, and egg shells
2 containers, such as buckets or cups
2 small pieces of plastic, such as milk container lids
Shovel
Soil thermometer or instant-read thermometer for meat
SAFTEY TIPS & HINTS
— Always call your local electric company before you dig to avoid underground power lines.
— This experiment will work best during months when it is warm outside.
PROTOCOL
STEP 1: Save some compostable waste from your kitchen. Divide the compost equally into two containers. Add a small piece of plastic to each container so you can observe what happens to plastic in compost heaps and landfills. (Fig. 1)
Fig. 1: Save some compostable waste from your kitchen.
STEP 2: Dig two holes in the ground. They should each be about 1 foot (30.5 cm) deep. (Fig. 2)
Fig. 2: Dig two holes in the ground.
STEP 3: Empty one compost container into each hole and cover them with dirt. (Fig. 3)
Fig. 3: Dump compost in the holes.
STEP 4: Label one compost pile “no water” and the other “water.”
STEP 5: Water the compost pile labeled “water” every other day or so.
STEP 6: When you water the compost, use a soil thermometer or another metal thermometer to check the temperature in each of your compost piles. Record it and compare it to the soil temperature in the surrounding areas. (Fig. 4)
Fig. 4: Check the temperature of the compost.
STEP 7: After several weeks, dig up your compost to observe how well things are breaking down. Spread it out on a tarp or plastic bag to get a closer look.
STEP 8: Put the compost back in the ground and add it to your garden as fertilizer when it is ready. Recycle the pieces of plastic.
CREATIVE ENRICHMENT
1. Test how packing down compost to limit oxygen or adding grass clippings and leaves affects compost.
2. Record how many worms you find in and near your compost piles.
LAB 38
PLANT RACE
CREATE A BOTANICAL OLYMPICS TO SEE HOW QUICKLY DIFFERENT PLANTS GROW.
MATERIALS
1 large planter, or several small flowerpots or cups
Potting soil
Ice pope sticks or wooden plant markers
A variety of seeds and dry beans
SAFTEY TIPS & HINTS
— Be aware that dry beans can be choking hazards for small children.
PROTOCOL
STEP 1: Fill the containers with potting soil.
STEP 2: Subdivide large containers with sticks, with a section for each type of plant in the race.
STEP 3: Label each pot or section according to which seeds you will plant there. (Fig. 1)
Fig. 1: Divide and label planting containers.
STEP 4: Plant seeds or beans in each pot or section according to directions on the package. (Fig. 2)
Fig. 2: Plant seeds or beans according to directions.
STEP 6: In your science notebook, make a guess, or hypothesis, about which plants you think will grow the fastest and why.
STEP 7: Observe the plants for a few weeks. Once they’ve sprouted, record in your notebook how tall they are each day and when leaves form. (Fig. 4)
Fig. 4: See which plants grow the fastest.
STEP 8: Check to see whether your experimental results agree with your hypothesis.
CREATIVE ENRICHMENT
1. Graph your results to make a growth curve for each type of seed. Do they start fast and slow down or continue to grow at the same rate?
2. Race the same type of seeds against each other, but water them with different liquids. Use tap water as a control.
3. See how density affects growth rate by racing seeds grown very close together against seeds grown far from one another.
LAB 39
GARDEN GUEST BOOK
MATERIALS
Notebook
Garden
Magnifying glass
Camera (optional)
Flashlight
SAFTEY TIPS & HINTS
— Visit the garden at different times of day and night.
PROTOCOL
STEP 1: Start a garden guest book section in your science notebook for garden visitors. (Fig. 1)
Fig. 1: Start a garden guest book.
STEP 2: Observe flower and vegetable gardens to find out what creatures are visiting. See what’s under leaves and crawling in the dirt, as well as who is sitting on plants and flying through the air. Use your magnifying glass for a closer look. (Fig. 2, 3)
Fig. 2: Look for spiders.
STEP 3: Use your garden guest book to record, draw, and insert photos of the creatures you observe. Keep track of the day and time you saw the visitors, which plants they were on or near, and what they appeared to be doing. (Fig. 4)
Fig. 4: Draw and describe the garden visitors you spot.
STEP 4: Try to identify the animals, birds, insects, and arthropods you observed.
STEP 5: Visit the same garden or gardens over several days at different times of day to see what you find. Observe gardens at night, with a flashlight, to discover nocturnal visitors.
CREATIVE ENRICHMENT
Did you find predators, for example, spiders? Make a garden guest food chain diagram that includes the plants in the garden. Where do you fit in?