Root rot is the most serious problem in a Kratky tomato, because the roots are the whole system. A plant with rotting roots wilts even though it is standing in water, because the damaged roots can't take that water up.
Healthy Roots vs Rotting Roots
| Healthy roots | Rotting roots |
|---|---|
| White to cream | Brown or tan |
| Firm | Soft and slimy |
| No smell, or an earthy smell | A sour or rotten smell |
| The plant stands up in the heat of the day | The plant wilts even with plenty of water |
What Causes It
Root rot starts when roots run short of oxygen. Weakened roots are then attacked by water molds such as Pythium.
- Overfilling. Topping up over the air roots drowns them, and drowned roots die and rot. This is the most common cause in Kratky. See topping up a Kratky tomato reservoir.
- Warm solution. Warm water holds less dissolved oxygen. Keep the container out of direct sun and away from heat sources; above about 75°F the risk rises.
- Light in the container. Light grows algae, which competes for oxygen. See algae in a Kratky reservoir.
- Dirty containers. Reusing a container without cleaning it can carry problems into the next crop.
What to Do
- Check the roots. Lift the lid and look. A few brown tips are not a crisis; a brown, slimy mass is.
- Restore the air gap. If the level is up near the net cup, remove solution until the remaining white roots are in air again.
- Cool the reservoir. Shade the container or move it somewhere cooler.
- Trim dead roots with clean scissors if the plant is small enough to lift.
- Replace badly fouled solution with a fresh mix in a clean container, set at the water roots' level. In a severe case this is the one time you change the solution.
A plant with only a small amount of healthy root left often won't recover. Start a new plant in a clean container, and keep the air gap from the start.
Back to Kratky tomato problems.
Frequently Asked Questions
What does root rot look like in Kratky?
Brown, soft, slimy roots, often with a sour smell, and a plant that wilts even though the container has water.
Can a Kratky tomato recover from root rot?
Sometimes. If some white roots remain, restoring the air gap and cooling the solution can let new roots grow. If most roots are brown and slimy, start a new plant.
How do you prevent root rot in Kratky tomatoes?
Keep the air gap by never topping up over the air roots, keep the solution cool and dark, and start each crop in a clean container.