Sowing tomatoes: time, temperature & procedure

Tomato cultivation begins early in the year. We show what needs to be considered and which substrate is best suited for growing tomato plants.

Tomatoes (Solanum lycopersicum) are the absolute favorites of many hobby gardeners. In summer, tomato plants adorn the vegetable beds and house walls in many gardens with their grass-green foliage and colorful fruits. But in order to be able to successfully grow tomatoes in your own garden, the sowing must first succeed. Preferring your own tomatoes is not only worthwhile for garden owners, but also for balcony gardeners. With a little space on the window sill, you too will soon have small seedlings growing towards the sun. In this article you will find instructions and helpful tips on how to sow tomato seeds.

Sowing tomatoes: when is the right time?

The right time to sow tomato seeds is between late February and late March. Proper young plants can then be planted in the greenhouse or bed in May. Tomatoes are among the vegetables with a long cultivation period. Pulling them forward gives the plants a head start indoors while it's still far too cold outside for the warmth-loving sun-worshippers. Tomatoes sown too early tend to wilt quickly, which means they develop very long shoots and often fall over because the sun is not yet strong enough to supply them with sufficient energy. Tomatoes that are sown too late do not produce fruit until late in the year, which may not ripen until autumn.

Sow tomatoes: temperature and location

To give preference to tomatoes, it is best to choose a warm and bright window sill. For the small tomato seedlings are Light and heat are particularly important. the The germination temperature for tomatoes should be 20 – 22 °C. In this way, the first seeds often germinate after just a few days. However, there are also solutions for dark and cool corners: LED lighting especially for plants can do that represent the color spectrum that is important for the tomato quite well and prevents the typical yellowing lack of light. A heating mat keeps the roots of the tomato plants warm even on cooler nights and encourages the seeds to germinate faster.

Step-by-step instructions for sowing tomatoes

When sowing tomato seeds, you should first decide on a suitable container. Here you can either use multi-plates made of plastic or on alternative sowing vessels set. An old egg carton or biodegradable pots made of coconut substrate are suitable for this, for example, but other containers can also be visually convincing. Since tomato plants are pricked out just a few weeks after sowing anyway, small growing containers with little soil volume are also ideal. A suitable seed soil for tomatoes must be permeable, water-storing and low in nutrients in order not to damage the tender roots. A low-salt and low-nutrient potting soil, like ours Plantura Organic Herb & Seed Soil, is ideal for this. Compact the substrate slightly with your fingers and refill with soil. Press the surface down a little and place the tomato seeds on top. The seeds are now covered with about 0.5 cm of soil. It is advisable to use stick-in labels or something similar so that you will know later which type of tomato you have sown. Inscriptions with pencil or waterproof felt markers also survive repotting and watering.

Now it has to be watered a little to stimulate germination. It is important that the soil is always slightly damp from this moment, but never wet. The freshly germinated, tender roots do not tolerate drying out very well at this stage. However, if the soil is wet for days, the seeds and roots can rot. It is therefore important to avoid both dryness and extreme wetness. A clear film cover or plastic hood will help maintain high humidity and reduce evaporation from the soil. This means that less frequent watering is required and it is easier for the seedlings to germinate and free themselves from the seed coat. Also a small seed greenhouse or a homemade one mini greenhouse are suitable for this. Depending on the variety and age of the seeds, the first little plants and cotyledons appear after just 3 - 10 days.

Sowing tomatoes: instructions at a glance

• Fill the seed container (multi-plate, pot or alternative container such as an egg carton) with nutrient-poor seed soil, compress slightly and refill again.
• Spread seeds on the surface, with approx. Cover 0.5 cm of soil and press down.
• Water the soil and seeds lightly and keep moist in the future.
• Place in a warm, bright location (preferably a window sill), alternatively illuminate with special plant LEDs.
• Transparent cover, mini greenhouse and heating mat accelerate germination.

tip: Sowing tomatoes is even easier with our Plantura vegetable growing set. It includes everything you need to grow vegetables successfully - seeds, nursery pots, substrate, plant labels and a reusable mini greenhouse. In addition to tomatoes, you can also sow radishes, chard, carrots and beets with the vegetable set.

After a few days to weeks, the tomato seedling will grow and should be transplanted into more nutrient-rich soil. We give tips how you Prick out and plant out the tomatoes.