How Do You Grow Kratky in a Closet or Grow Tent?
A Kratky grow tent or closet gives plants steady light every day of the year, in a space you can close the door on. The light does the work; the parts to plan are heat and air, because an enclosed space traps both.
Kratky suits an enclosed space well. There is no pump to hum, nothing to plumb in, and nothing to break while the door is shut. A grow tent, a spare closet or a cabinet all work the same way.
Closet or Tent?
- Closet: free if you have one spare. Line the walls with something white or reflective so light isn’t lost. Keep clothes and boxes out: they block air and can get damp.
- Grow tent: a fabric frame with a reflective lining, a zip door and ports for cables and a fan. It keeps light in, keeps the mess contained, and comes in sizes from a small cube to tall enough for tomatoes.
For lettuce and herbs, a small tent or a closet shelf is plenty. Size the space to the plants you grow, not the other way round.
Lighting the Space
An LED grow light is the usual choice: it puts out less heat than older lamp types for the same light. Hang it so its height can change as plants grow. Run it on a timer, about 14 to 16 hours a day for lettuce and herbs. Plants need some hours of darkness; the 24-hour light article explains why.
For help choosing the light itself, My LED Grow Lights compares models by size and output.
Heat
An enclosed space with a light running warms up. Warm solution holds less oxygen, and in Kratky that oxygen matters. Aim to keep the solution cool, ideally below about 75°F (24°C).
- Put a thermometer inside, at plant height, and check it when the light has been on for a few hours.
- Keep containers off the top shelf, where warm air collects.
- Use opaque, light-colored containers, which absorb less heat than black ones.
Moving Air
Still air in a closed space gets humid and warm, which invites mold on leaves. A small clip fan inside, pointed so the leaves move gently, helps. In a tent, a small extractor fan in the top port pulls warm air out. In a closet, leaving the door open a crack for part of the day does the same job.
A Setup Checklist
- Reflective or white walls.
- LED light on an adjustable hanger and a timer.
- Thermometer at plant height.
- A small fan for airflow.
- Covered, opaque containers on a tray.
- Cables run high, away from where solution could drip.
What Grows Well
Lettuce and other leafy greens, basil and most herbs do very well. Taller crops such as tomatoes and peppers need a tall tent, a stronger light and large containers. Start with greens and work up.
Common Mistakes
- Shutting the light in with no airflow.
- Hanging the light at one height and never adjusting it.
- Putting plugs and power strips on the floor of the tent, where spills land.
Common Questions
Is a closet good enough for Kratky?
Yes. Line it with white or reflective material, add a light on a timer and a small fan, and keep the door open a crack for air.
Do I need an exhaust fan in a small grow tent?
For a few lettuce plants under a small LED, a clip fan inside is often enough. If the solution or air runs warm, add an exhaust fan.
How many hours should the light run in a tent?
About 14 to 16 hours a day for lettuce and herbs, on a timer, with the rest of the day dark.
Related guide: growing Kratky under grow lights.
Related article: Does Grow Light Heat Warm Kratky Water?