Grow Spaces
Kratky for Classrooms and Kids' Projects
A Kratky container is cheap, quiet and has no moving parts, which makes it a good growing project for a classroom, a club or a family. This guide is for the adult running it.
Why Kratky Works for Groups
There's no pump to break and no daily watering, so the project survives weekends. Each student or child can have their own jar, and roots, leaves and the falling water level are all easy to see and measure.
Safety First
Hydroponic nutrients are concentrated, and pH-down products are acids. The adult should handle both:
- Mix the nutrient solution yourself, following the label, and store products out of reach.
- Wear gloves and eye protection when the label calls for them.
- Label each container clearly so nobody mistakes the solution for drinking water.
- Wash hands after handling plants or solution.
What to Grow
Pick fast, forgiving plants so the group sees results within the term: loose-leaf lettuce, basil and other herbs. Avoid fruiting crops; they take longer and need much bigger containers.
Setting Up
- One wide-mouth jar or small opaque container per plant.
- A sleeve or wrap around each jar to keep light out. To let children see the roots, use a sleeve they can slide up for a quick look.
- The brightest window in the room, or a grow light on a timer if the windows are dim.
Ideas for Learning
- Mark the water level each week and graph how fast each plant drinks.
- Draw or photograph the roots as they grow into the air gap.
- Compare a jar on a sunny sill with one in a dimmer spot.
Weekends and Holidays
A short weekend is no problem. Before a long break, check every container has enough solution, or send plants home with families.
Classroom Checklist
- Adult mixes and stores nutrients and pH products
- Containers labeled and wrapped
- Quick-growing greens and herbs
- Plan for long breaks
