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Grow plants without soil. Learn how it works.

Short lessons on hydroponics, aquaponics, and the future of growing food, with something to try in every one.

Start learning For teachers

How it works

Learn it, try it, check it.

  1. 1

    Start with something you know

    Every idea begins with a picture from everyday life. A snack in a locked box explains pH.

  2. 2

    Try it with your own hands

    Move a slider, sort cards, or fix a sick plant. Watch what changes.

    Iron Calcium Phosphorus
    pH 6.2
  3. 3

    Check what you know

    Quick questions with a reason for every answer. Wrong picks get a nudge, never a red X.

    The pH Right Not quite
    More plant food Right Not quite

The course

Pick a track. Start anywhere.

See the full course map

Track 1

How plants really grow

What plants really need, what soil does, and how roots, light, and water work together.

  1. 1 What a plant actually needs
  2. 2 What soil does, and what it does not do
  3. 3 Roots: drinking, eating, breathing
  4. and 3 more
6 lessons
Start track

Track 2

Hydroponics

Grow without soil: six systems, mixing plant food, pH, air at the roots, and a jar project.

  1. 7 Growing without soil
  2. 8 Six ways to do it
  3. 9 The nutrient solution
  4. and 6 more
9 lessons
Start track

Track 3

Aquaponics

Fish and plants as partners, and the tiny crew of bacteria that links them.

  1. 16 Fish and plants as partners
  2. 17 The bacteria you cannot see
  3. 18 The nitrogen cycle, step by step
  4. and 5 more
8 lessons
Start track

Track 4

Feeding the future

Farms in cities, deserts, and space, and the people who grow our food.

  1. 24 Water, land, and why growing methods matter
  2. 25 Farms in cities, deserts, and space
  3. 26 Jobs in growing: who works in this field
3 lessons
Start track

Hands-on

Simulations to play with

Lesson 10

The pH slider

Slide the pH up and down. Watch nutrients lock and unlock, and see the leaves change.

Try it

Lesson 14

Plant doctor

Read the clues, check the readings, and work out what is wrong with a sick plant.

Try it

Lesson 21

Balance the tank

Change the fish, the food, and the plants. Keep the fish calm and the plants growing.

Try it

Your guide

Meet Sprout

Sprout is a seedling living in a net pot, roots dangling into the water. Sprout gives hints, cheers you on, and wonders out loud. Sprout never lectures.

For teachers and parents

Ready for class tomorrow

Each lesson fits a class period. Everything is free to use, with nothing to sign up for.

Go to the teacher pages
  • A one-page guide for every lesson, with answers
  • Printable worksheets, one page, black and white
  • A hands-on project: lettuce in a jar
  • Works offline after the first visit
  • No accounts, ads, or tracking

Ready to grow something?

Lesson 1 takes about six minutes.

Start learning