How Long Can You Leave Kratky Plants Unattended?

You can leave Kratky unattended for longer than almost any other way of growing, because there is nothing to switch on and the plant draws the solution down by itself. A weekend is never a problem. A week or two is usually fine if the container has enough solution for that stage of growth.

How long depends on three things: how big the plant is, how big the container is, and how warm it is. A small lettuce plant in a large container can go weeks. A big basil plant in a quart jar on a hot day can drink a lot in a few days.

How Much Solution a Plant Uses

Young plants drink very little. Use climbs steeply as the plant grows, and peaks just before harvest. Warmth, bright light and moving air all increase it. As a guide, a single lettuce plant in a container of about a gallon (4 liters) often finishes the whole crop without a top-up, while herbs grown for months need topping up from time to time.

Before you go, look at how far the level has fallen in the last week. That is the best estimate of what the plant will use while you are away, and the plant will usually drink a little more as it grows.

Before a Week Away

1. Check the level. If the plant will drink the container nearly dry while you are gone, top it up, but only part way (see below).
2. Harvest anything close to ready, so it doesn’t bolt or go past its best.
3. Move containers out of hot spots, such as a sunny window that heats up in the afternoon.
4. Put lights on a timer so they keep their normal hours.
5. Make sure every container is covered, so no light reaches the solution.

How to Top Up Before You Go

The air gap matters. The upper roots in Kratky breathe from the air between the solution and the net cup. If you fill a container back to the top, those roots sit underwater and can rot while you are away.

Add solution so it covers only the lower part of the root mass, and leave the upper roots in air. A good rule is to add no more than about half of what has been used. If the plant will need more than that, use a larger container next time.

Longer Trips

For two weeks or more, plan the crop around the trip:

• Start new plants just before you leave. Seedlings drink so little that a full container lasts weeks.
• Use the largest container that fits, so there is more solution per plant.
• Ask a neighbor to glance at the levels, if you can. Point to the line where the solution should be.

When You Get Back

Check the level, the color of the solution and the roots. White or tan roots are healthy. Brown, slimy roots and a bad smell mean the solution got too warm, so start that container fresh.

Common Mistakes

• Filling every container to the brim before leaving, which drowns the air roots.
• Leaving full-grown plants in small jars on a sunny sill.
• Forgetting the timer, so the lights run all day or not at all.

Common Questions

Related guide: growing Kratky in apartments and small spaces.

Related article: Can You Grow Kratky in a Dorm Room?