The Science of
Gardening &
Farming
Find out how plants make food, what soil really is, how peas feed the soil, why chinooks, frost and hail matter so much in Alberta, and how pollinators and pests shape every harvest.
- 00First Principlesp.2
- 01How plants make foodp.4
- 02Soil, Alberta stylep.5
- 03Nitrogen & rotationp.6
- 04Chinooks, frost & hailp.7
- 05Pollinators & pestsp.8
- ✦Self-check · Make it · 5 Questions · Side Questp.9
You'll need: pencil, a clear jar, seeds, a ruler and a thermometer if you have one.
Principles
A first principle is a basic truth you can build on. Growing science rests on four: plants make food from light, soil is alive, nutrients cycle and weather sets the limits.
What do I already know?
What is necessary?
Everything in this module is built from four bricks. Rate yourself on each one, then check the example to see if your rating holds up.
What is the objective?
By the end, you’ll be able to explain photosynthesis, test soil texture, describe Alberta’s soil zones, explain how pulses add nitrogen and why farmers rotate crops, explain chinooks, frost and hail, and describe how pollinators and pest management work.
- 01Explain photosynthesis and plant needs.
- 02Test soil texture with a jar.
- 03Describe Alberta’s soil zones.
- 04Explain nitrogen fixation and rotation.
- 05Explain chinooks, frost and hail.
- 06Describe pollinators and pest management.
The list on the left is ours. Now make it yours. What do you want out of this?
How much do you know about the science of gardening and farming right now? Shade the boxes in pencil. You'll come back at the end (p.9) and shade it again in pen.
Why start this way? When you know what you already have (1), what you need (2) and where you're going (3), you learn faster and you notice the gaps. Every module on the Gardening & Farming Path starts with these same three questions.
How plants make food
Every bite you eat started as sunlight caught by a leaf.
Sugar from sunlight
In their leaves, plants use the green pigment chlorophyll to capture light energy. They combine carbon dioxide from the air (taken in through tiny pores called stomata) with water from the roots to make glucose (sugar), and release oxygen.
6CO2 + 6H2O + light → C6H12O6 + 6O2
Five things
- Light: most vegetables want 6 or more hours of sun a day.
- Water: carries nutrients up from the roots and keeps cells firm.
- Air: CO2 for leaves, oxygen for roots (soggy soil drowns them).
- Nutrients: nitrogen, phosphorus, potassium and more, from soil.
- The right temperature: cool crops (peas, lettuce) and warm crops (tomatoes, squash).
A famous surprise
In the early 1600s, Jan Baptist van Helmont grew a willow in a pot of weighed soil for five years. The tree gained about 74 kg; the soil lost only about 57 g. He thought the mass came from water. Today we know most of a plant’s dry mass is carbon, pulled from the air as CO2.
- A huge tree is made mostly from air and water. Does that surprise you? Why?
- Why do plants in a shady corner grow tall and thin?
Light test
Grow two pots of fast seeds (radish, cress): one in a sunny window, one in a dim corner. Measure and compare after 10 days.Why do leaves turn yellow when a plant is kept in the dark?
Soil, Alberta style
Soil takes hundreds of years to form and can blow or wash away in a season.
Not just dirt
- Minerals: sand (gritty), silt (smooth) and clay (sticky) in different mixes; that mix is the soil’s texture.
- Organic matter: rotting plants and animals; makes soil dark and holds water.
- Water and air in the spaces between grains.
- Life: a handful holds billions of bacteria and fungi, plus worms and insects.
Drier south, wetter north
Grassland soils called Chernozems cover much of farm Alberta. From the dry southeast to the moister centre they run Brown → Dark Brown → Black, getting darker as grass added more organic matter. Farther north and west, under forests, are lighter Gray Luvisolic soils.
Government of Alberta, Agricultural Land Resource Atlas of Alberta.
The jar test
Soil without cover can blow away. In the 1930s, drought and bare, over-tilled fields helped cause huge dust storms on the Prairies (Lens 5). Today many farmers leave crop stubble on fields to protect the soil.
- How could you tell good soil from poor soil without a lab?
- Why might two farms a few kilometres apart have different soil?
Squeeze test
Wet a little soil and squeeze it. Gritty and falls apart: sandy. Smooth: silty. Sticky ribbon: clay. What’s yours?Why are Black soils near Edmonton so good for crops?
Nitrogen & rotation
The air is full of fertilizer. Only some plants, with tiny helpers, can use it.
Peas that feed the soil
Air is about 78% nitrogen gas, but plants can’t use it directly. Pulses (peas, lentils, faba beans, beans) team up with rhizobia bacteria that live in little bumps (nodules) on their roots. The bacteria turn nitrogen from the air into a form plants can use; the plant feeds them sugar.
Dig up a pea plant in summer: pink nodules mean the team is working.
Change it up each year
- A common Prairie pattern: canola → wheat → peas (or barley), then repeat.
- Pulses leave nitrogen for the next crop.
- Rotating breaks the life cycles of diseases, weeds and insects that like one crop.
- Gardeners rotate too: don’t plant tomatoes or potatoes in the same spot every year.
Feeding a crop
Most large farms add synthetic nitrogen fertilizer, made from natural gas. It greatly raises yields and helps feed the world, but extra nitrogen can wash into water and some becomes nitrous oxide, a greenhouse gas. Others rely more on manure, compost and pulses. Many farmers combine methods, aiming to use the right source, rate, time and place (often called “4R” stewardship).
- Why might a farmer plant peas one year and wheat the next?
- What could happen to a river if too much fertilizer washes off a field?
Nodule hunt
Grow a pea or bean plant in a pot. After 4–6 weeks, gently wash its roots. Draw what you see.Why might a farmer plant peas the year before wheat?
Chinooks, frost & hail
Alberta weather can swing from winter to spring and back in a single day.
The snow eater
A chinook is a warm, dry wind that blows down the east side of the Rockies. Pacific air rises over the mountains, cools and drops its moisture, then warms quickly as it sinks. Temperatures can jump in hours. On January 10, 1962, Pincher Creek warmed from −19 °C to 22 °C, a 41-degree rise, often reported as within about an hour.
Chinooks melt snow, but can dry soil and fool plants into waking early before the cold returns.
Alberta’s big risks
- Frost: on clear, calm nights, heat escapes and low spots get coldest. Covers and a row of buckets of water help.
- Hail: central Alberta, especially between Calgary and Red Deer, is one of Canada’s hail hot spots. Most hail falls in June to August afternoons.
- Drought: the southeast, called the Palliser Triangle, is especially dry.
June 13, 2020
A hailstorm in northeast Calgary caused about $1.2 billion in insured damage: homes, cars and gardens. Farmers can buy hail insurance; Alberta’s crown corporation AFSC offers crop and hail coverage.
Insurance Bureau of Canada and CatIQ (2020).
- A chinook melts snow in February. Is that good or bad news for a garden? Explain both sides.
- How would you protect a garden from a hailstorm forecast?
Weather watch
For 2 weeks, record the high, low, wind and any frost, rain or hail where you live. Did a chinook come through?Why does sinking air warm up?
Pollinators & pests
Some insects make the harvest possible. Others try to eat it first.
Who moves the pollen?
Many fruits and seeds form only after pollen moves from flower to flower. Honey bees, Canada’s hundreds of native bee species (like bumble bees), flies, butterflies and moths all help. Squash, cucumbers and many fruits need insect visits; wheat and barley mostly pollinate themselves.
Alberta produces about 40% of Canada’s honey, much of it from canola and clover fields.
Government of Alberta, 2024 Beekeepers’ Survey (42.6% in 2024).
Smart, layered defence
Weighing risks and benefits
Farmers use herbicides, insecticides and fungicides to protect yields; Health Canada’s Pest Management Regulatory Agency reviews each product before it can be sold. Some people worry about effects on bees, water and health and prefer organic or low-input methods. Others point out that higher yields can mean less land is farmed. Evidence differs by product, dose and use.
- What would your lunch look like without pollinators?
- Why try other pest controls before spraying?
Bug survey
Spend 15 minutes watching flowers in a garden or park. Tally every visitor: bee, fly, butterfly, other. Which flower was busiest?Why might spraying an insecticide on open flowers harm a crop’s harvest?
Quick self-check
Six questions, covering every stop. Show your thinking. Answers are upside down at the bottom; no peeking till you're done.
1 · What do plants make in photosynthesis, and what gas do they release?
2 · What are the three mineral parts of soil texture?
3 · Name Alberta’s three Chernozem soil zones from dry to moist.
4 · What do rhizobia do?
5 · What is a chinook?
6 · Name two steps of integrated pest management.
Re-shade your knowledge meter
How much do you know about the science of gardening and farming now? Flip back to p.3 and shade the meter again in pen (or shade this one). Did any of the four bricks on p.2 move from "Not yet" to "Got it"?
The fair-test sprout race
Run a fair experiment: two pots of peas, one with light and one without, and measure what happens.
1 · Set up
Soak 20 pea or bean seeds overnight. Plant 10 in each of two pots with the same soil. Pot A goes in a sunny window; pot B under a box with a small hole, or in a dim corner.
- Same seeds, soil and water in both pots
- Label pot A and pot B
- Measure every 2 days
- Draw both at day 14
2 · Height log (cm)
| Day | Pot A | Pot B |
|---|---|---|
| 2 | ||
| 4 | ||
| 6 | ||
| 8 | ||
| 10 | ||
| 14 |
3 · Must-haves
- One thing changed (light)
- Everything else kept the same
- Data in a table and a graph
- A conclusion with evidence
4 · What I found
Which pot grew taller? Which was greener and sturdier? What does this show about photosynthesis?
Some seeds sold for planting are coated with chemicals: wash your hands after handling them, and never eat seeds meant for planting. Keep pots where small children and pets can’t reach them.
5 Questions
I Still Have
This module didn't answer everything. Good. Write 5 new questions it didn't answer, one of each type below. There are no wrong questions, only ones nobody's asked yet.
★ Star the one question you'd most like answered. You'll need it on the next page.
1What I'll find out
Break your big question into 2 or 3 smaller ones you could actually answer.
2Where I'll look
3How I'll share it
Who I'll share it with:
Done by: