Kratky Kit on Vacation: How Long It Can Be Left Alone

One of the best things about a Kratky kit is that it keeps growing while you are away. There is no pump to fail and nothing to water. How long it can be left depends on one thing more than any other: whether the solution in the reservoir will last until you get back.

The short answer

A Kratky kit with a well-sized reservoir can often be left for one to several weeks. Young plants drink little, so a kit planted a week or two before you leave is the easiest to leave. A large plant near harvest drinks fast and can empty a small jar in days. Plan around the plant's size and the container's volume, not a fixed number of days.

Why Kratky suits being left

• No electricity, so no risk from a power cut or a failed pump.
• The falling level is part of the method; the plant keeps getting oxygen from the air gap. See the Kratky air gap.
• No daily watering or feeding.

How water use changes over a crop

Typical water use in a Kratky kit through a leafy green crop

Stage	Plant	Water use	Leaving it
Just transplanted	Seedling, small roots	Low	Easiest; check roots touch the solution
Early growth	Several true leaves	Rising	Good time to leave with a full reservoir
Full growth	Large, leafy	Highest	Risky in a small container
Ready to harvest	Full size	High	Harvest before you leave

Warm rooms, strong light and air flow all raise water use. A kit in a cool room in winter will last longer than the same kit in a sunny summer window.

Before you go

1. Look at the level. If the reservoir has already dropped a lot and the plant is large, it may not last.
2. Harvest anything that is ready. A finished crop left for two weeks may bolt.
3. Do not refill to the top. If the plant needs more solution, add a little below the air roots, as the guide on how often to refill a Kratky kit explains.
4. Block light from the solution. Two weeks is plenty of time for algae to take hold in a clear jar.
5. Move it out of hot spots. Turning the heating down or the air conditioning off can change a room's temperature. Keep the reservoir out of direct sun. Warm solution raises the risk of root rot.
6. Set any grow light on a timer so it keeps its normal schedule.

Plan a crop around a trip

If you know a trip is coming, start the crop so that the plants are young when you leave. A lettuce transplanted shortly before a two-week trip will usually be fine in a container of around a gallon. Choosing a bigger reservoir from the start gives more margin. The Kratky containers guide gives rough sizes per plant.

Several plants in one container

A tote with several plants drinks much faster than a single plant in a jar. If you grow several together, give the container plenty of volume or reduce the number of plants before a long trip.

When you get back

• Lift the lid gently and look at the level and roots. White roots and a lower level are normal.
• If the solution is gone and the plant is wilted, add a small amount of fresh solution so the root tips reach it. Do not flood the upper roots.
• If the plant has bolted, harvest what is usable and start again.
• If the plant is ready, harvest it. The Kratky harvest guide covers how.

Leaving a classroom kit over a break

School holidays are the most common long absence for Kratky kits. Start fast crops so they are harvested before the break, or plant just before it so the seedlings are small. A larger reservoir and a cool spot help. The article on a Kratky kit for kids has more classroom tips.

For the basics of running a kit, see the Kratky kit setup guide.

Frequently asked questions