Why My Tomato Plants Are Not Growing?

Even the most patient amateur gardener will eventually notice when his tomato plants or later the tomatoes themselves do not grow. Read in this article what causes this and what you can do to accelerate the growth.

Even after successful sowing and subsequent pricking out, it can happen that the young plants in the bed or tub do not really tolerate the move. Instead of a strong increase in size and volume, nothing or only little happens. This can have temporary reasons or in the worst case permanent. This can have several causes:

Tomatoes are not hardened or resistant enough

Tomatoes are very sensitive plants that react strongly to external influences, including temperature, especially in the growth phase. Before you expose your tomatoes outdoors, you should definitely put them on the balcony or terrace during the day for at least 1-2 weeks beforehand. In this way, the seedlings get used to the external weather and build up resistance to temperature fluctuations.

Tip: Effective microorganisms sprayed on the sprouts, seedlings and tomato plants make the sensitive tomato plants noticeably more robust and resistant to external influences. Effective Microorganisms (EM) are liquid strains of bacteria & ferment-active fungi that allow plants to better absorb nutrients.

Tomaten sind nicht abgehärtet zu schwach zu klein

Too little protection from frost or sowing too early.

A similar issue is the general protection against, for example, frost in the soil. The best hardening off against outside temperatures is of no use if the tomato plants were simply set out too early. Make sure that the soil is frost-free up to the root tips and cover the plants at night with fleece, for example. Otherwise, you can’t expect the tomatoes to go into growing mode before mid-May. Early sowing even when temperatures are apparently good simply makes little sense earlier.

Bad location for tomatoes

You know, of course, that a tomato plant needs plenty of light and heat to ensure optimal growth. Actually, every amateur gardener pays attention to a nice sunny and bright place at the time of planting tomato plants but do they also pay attention to a permanent supply of sun? Here’s what the best location for optimal tomato growth looks like:

  • sunny, warm location without air barriers.
  • best protected from rain
  • loose soil with permanent light moisture
  • nutrient-rich soil (e.g. with Bokashi ferment at the root tips)


Tip: in very hot temperatures, tomatoes should also be given an opportunity for shade. This will prevent heat buildup that keeps temperatures above 30 degrees for a long time.

Why tomatoes do not germinate

The situation is different if you have problems getting the tomato seeds to germinate at all. Therefore, it is best to ensure the optimal conditions for the tomato seeds in advance. For the seeds, the right interaction of light and heat is essential. That is why seeds in Central Europe are always grown in the apartment or greenhouse. Only here can the following conditions be ensured.

  • Semi-shaded place without permanent direct sunlight
  • Temperatures around 20 degrees (18 – 24 degrees)
  • No fertilizing


Even though tomato seeds are light germinators, permanent sunlight is not beneficial. The germs would otherwise burst too quickly or dry out. On the other hand, the situation is quite different for seedlings.

Tomatoes seedlings do not grow


If you have done everything right during sowing, the first tiny leaves will push through the seed coat after about 14 days. Now you should move the seedlings first to prevent the so-called Geilwuchs (Vergeilen). The tomato seedlings grow in semi-shaded places much faster than necessary and form too thin shoots that later fold over quickly in the open air and have little load-bearing capacity.

Therefore, you should now give the seedlings more light and less temperature. Permanent light irradiation at 16 to 18 degrees is the optimal environment here for the entire transition phase until the move out in May to the final location.

Tomatoes are not sufficiently fertilized or overfertilized


If your tomatoes have successfully mastered the start-up difficulties but in the middle of the growth phase have problems with, for example, flower formation or fruit growth, incorrect fertilizing behavior may also be the reason.

Among gardeners, the principle prevails that nitrogen fertilizer generally accelerates growth. But where exactly is this true? With tomato plants e.g. grow up to the fruit formation with too much nitrogen only the plants in the height and neglect thereby the flower formation. Therefore, help with nitrogen from e.g. horn shavings at the earliest when the flowers are in full bloom.

Also, overfertilizing the soil prevents nutrient and water absorption. So check carefully beforehand how much fertilizer is sufficient for efficient growth. Tomatoes should always be fertilized in a balanced way.

Tip: Since a tomato plant itself knows best what it needs to grow, we recommend a fertilizer ferment made from Bokashi (e.g. Tomato Bliss) This soil additive is buried directly into the soil and serves as an ideal nutrient medium for the tomato plant. Through Effective Microorganisms, the tomato root dissolves exactly the nutrients from the complete fertilizer that it needs at the moment.

Tip for resistant tomatoes and tomato plants: Effective microorganisms
We recommend in general, but for poorly growing tomatoes in particular, treatment of tomato plants with effective microorganisms. These are liquid mixed cultures consisting of bacterial strains and ferment-active fungi. They allow the plants to better absorb nutrients and displace rot pathogens.

Water your seedlings with a mixture of 1 part EM active with 400 parts water (e.g. 10 ml to 4 liters of watering water). In addition, consistent spraying of the seedlings with this EM aktiv dilution helps with the side effects of growth disorders. The plant structure improves, making the tomato more resistant to disease and favoring nutrient uptake.

The irrigation water can also be energized with EM ceramic pipes. This favors not only the water quality but also the vitality of the soil.

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