Tomato seeds need the bright red spectral range of sunlight to germinate. Botanists therefore classify them as light germinators. With a beam of light, however, only part of the germination conditions are met. Find out what else is included here.
Why are tomatoes light germinators?
Tomato seeds are light germinators that require the bright red spectral range of sunlight to germinate. In addition, a constant temperature of 18-24°C, slightly moist seeds and pretreatment, such as steeping in lukewarm chamomile tea, are beneficial for germination.
Pretreatment increases germination readiness
The cultivation of tomato plants behind glass begins at the end of February/beginning of March. The seeds you harvest yourself or buy are not naturally ready to germinate. After a simple pre-treatment, the germination mood improves immensely:
- Soak tomato seeds in lukewarm chamomile tea for half a day
- It also works in diluted garlic juice in a ratio of 1:10
This process not only promotes germination, but also strengthens resistance to mold spore infestation.
Light alone does not allow tomato seeds to germinate
If the cultivation pots are filled with nutrient-poor substrate, sow the prepared seeds at a distance of 3 centimeters. The seeds may be covered with soil or sand by a maximum of 0.5 centimeters. From this point on, the following factors should complement each other so that the tomato seeds germinate quickly:
- In a partially shaded location, enough light reaches the seeds so that they reach the light red spectral range
- there is a constant temperature of 18 to 24 degrees Celsius
- the seeds are kept slightly moist
Sowing should not be done under direct sunlight. The tender seeds would spoil within a short time. Normal daylight is sufficient to encourage the light germs to become active. Under ideal conditions, the germination period is between 10 and 14 days. Pricking takes place as soon as the first pair of real leaves has developed.
Tips & Tricks
Since light germinators are always at risk of being washed away by irrigation water, clever hobby gardeners use the following trick. Instead of watering the seeds from above, they administer the water from below. To do this, half of the growing pots are submerged in water. Due to capillary action, the substrate absorbs moisture. As soon as the seed soil is moist to the surface, the pots go back into the indoor greenhouse (€24.00 on Amazon).
