FAQ
Kratky Hydro FAQ
Short answers to common questions about growing with the Kratky method in different spaces. Each answer links to the guide that covers it in full.
Getting Started
What is the Kratky method?
Passive hydroponics: a plant sits in a net cup over a container of nutrient solution. As the plant drinks, the level drops and an air gap forms for the upper roots. There's no pump. See all grow spaces.
Do I need electricity?
No. The container itself is fully passive. You only need power if you add a grow light. Kratky off-grid.
Do I need to top up the water?
For most leafy greens and herbs, one fill lasts to harvest. Larger plants drink more and may need solution added part-way through. Don't refill to the very top, or you'll drown the roots that grew into the air gap.
Choosing a Space
Can I grow on a windowsill?
Yes, if the window is bright. Herbs and leafy greens do best. Kratky on a kitchen windowsill.
Will it work in an apartment?
Yes. It's silent, needs no plumbing and fits on a shelf. Kratky in apartments and small spaces.
Can I grow Kratky outdoors?
Yes, with protection from rain, heat and mosquitoes. Kratky on a balcony or patio.
Do I need a grow light?
Only if your windows don't get enough light, or you want steady growth in winter. Kratky under grow lights.
Does Kratky work in a greenhouse?
Yes, as long as you keep containers from overheating in summer and freezing in winter. Kratky in a greenhouse.
Is Kratky a good classroom project?
Yes. It's cheap, has no moving parts and survives weekends. An adult should handle the nutrients. Kratky for classrooms and kids' projects.
Containers and Problems
Why is there green slime in my container?
Algae, from light reaching the solution. Use opaque containers or wrap clear jars. Every grow space guide covers this for its setting.
Can I use mason jars?
Yes. Wide-mouth jars fit a standard net cup. Wrap them to keep light out. It's how we grow indoors. Kratky on a kitchen windowsill.
