What Supplies Do You Need for Classroom Kratky?
A classroom Kratky setup needs only a few things: opaque containers with lids, net cups, a growing medium, seeds, hydroponic nutrient and a way to measure it. This list covers every Kratky classroom supply, plus the safety gear and the optional light.
Buy for the number of containers, not the number of students. Small groups sharing one container each are easier to manage than a container per student.
Growing Supplies
- Containers: opaque, about 1 to 2 quarts (1 to 2 liters) each, with a stable base. Recycled food tubs work if they are opaque and clean.
- Lids: one per container, with a hole cut to hold the net cup snugly.
- Net cups: 2 to 3 inch (5 to 7.5 cm) cups suit lettuce and herbs.
- Growing medium: rockwool cubes, coco coir plugs or clay pebbles to hold the seed or seedling.
- Seeds: loose-leaf lettuce and basil are the most reliable. See the best plant article.
- Hydroponic nutrient: a nutrient made for hydroponics, not a garden fertilizer. A one-part nutrient is simplest for a class.
Measuring and Testing
- A measuring syringe or measuring spoons for the nutrient.
- A measuring jug and a bottle with a lid for mixing solution.
- A liquid pH test kit or test strips.
- A ruler, and a marker to note the solution level on each container.
Safety and Clean-Up
- Gloves, and eye protection if the nutrient label says so, for the adult who mixes it.
- Labels for every container and the mixed solution.
- Paper towels and a tray under the containers.
- A lockable cupboard or high shelf for the nutrient.
Optional: A Light
If the classroom window is dim, a small LED grow light on a plug-in timer gives every container the same light. That also helps if the class is running a science fair project, where every plant needs equal conditions.
For Learning
- A clear container with a removable sleeve, so students can see the roots. The roots without algae article shows how.
- A growth chart for each container.
- A camera or tablet for weekly photos.
Kits or Separate Parts?
A kit puts containers, net cups, medium and nutrient in one box, which saves time and makes ordering simple. Kratky Hydroponics Kit covers kits in detail. Buying parts separately costs less per container for a large class.
A Shopping Checklist
- Containers and lids
- Net cups and growing medium
- Seeds
- Hydroponic nutrient
- Syringe, jug, bottle and pH kit
- Gloves, labels, towels and a tray
- Optional: light and timer
Common Questions
Can I use clear containers in the classroom?
Only with a cover. Clear containers grow algae. Use a removable sleeve if students need to see the roots.
Which nutrient is best for a classroom?
A one-part hydroponic nutrient is simplest. Follow the label rate for leafy greens.
Do I need a pH kit for classroom Kratky?
It is useful, especially with hard tap water. Liquid kits and strips work without power and are easy for students to read.
Related guide: running a Kratky classroom project.
Related article: What Can You Test in a Kratky Science Fair Project?