Etiolation
Etiolation describes the unnaturally fast, elongated growth of young plants. The shoots become thin, soft and unstable, with unusually large gaps between the leaves. The cause is almost always a lack of light combined with too high a temperature.
Why do plants become etiolated?
When plants receive too little light, they stretch strongly upwards to reach a better light source. This so-called "legginess" occurs particularly often when raising seedlings on the windowsill in February and March.
Typical causes are:
- A position that is too dark
- Room temperature that is too high
- Seedlings standing too closely together
- Sowing too early in the year
How do you recognise etiolated plants?
- Long, thin and unstable stems
- Pale, often light green leaves
- Large gaps between the leaf nodes
- Seedlings toppling over
What can you do against etiolation?
The most important measure is more light. A very bright position or a grow light is ideal. At the same time, the temperature should be lowered slightly after germination. Many vegetable crops such as tomatoes or brassicas grow more compactly at 16–18°C than at 22°C.
Seedlings that have already become etiolated can sometimes be saved. Tomatoes can be planted deeper when pricking out, as they form additional roots along the stem. Other plants should be moved to a brighter, cooler spot as soon as possible.
Preventing etiolation
Choosing the right sowing time is crucial. Anyone sowing in late winter should ensure sufficient light or wait until March. Strong, compact young plants are the best foundation for healthy, high-yielding plants in the garden.