Why isn't your tomato seedling growing? Here are four key reasons to consider.

Sometimes, when tomato seedlings are not growing, it may be due to several factors. Typically, issues arise from improper care, temperature fluctuations, nutrient deficiencies, or diseases. If your seedlings have stopped growing, it is essential to analyze what might be the cause and how to address it. More details on this topic are discussed by Vkazivka.

Unfavorable Microclimate

One of the primary reasons for the stunted growth of seedlings is an incorrect microclimate. For tomatoes, critical factors include temperature, humidity, and lighting. If the room temperature is too high (above +32°C), growth processes may halt. Conversely, excessively low temperatures can also hinder plant development. It is advisable to ventilate the space and, if necessary, reduce the temperature. To normalize humidity, a spray bottle can be used to mist the plants with water.

Proper lighting is also crucial: tomatoes require 12-16 hours of light per day. During the short winter days, natural light may be insufficient, so supplemental lighting with grow lights can help the plants develop correctly.

Nutrient Deficiency

A lack of nutrients can also lead to slowed seedling growth. If the leaves turn yellow or pale, this may indicate insufficient nitrogen levels. If the leaves take on a bluish or purplish hue, it suggests a phosphorus deficiency. In such cases, it is important to fertilize the plants promptly. Urea can be used to replenish nitrogen, while superphosphate can address phosphorus needs. These fertilizations should be done 10 days after germination and repeated during the transplanting phase and before planting in the soil.

Improper Transplanting

Transplanting is a critical process that can significantly affect seedling development. Incorrect repotting, root damage, or the formation of air pockets in the soil can cause seedlings to stop growing. During transplanting, it is vital to pinch the main root to encourage the development of lateral shoots. Failing to do so may result in elongated seedlings that do not grow well.

Diseases and Pests

Seedlings may fail to grow due to various diseases. One of the most common is damping-off, which leads to stem rot at the soil level. To combat this infection, it is crucial to remove diseased plants and treat healthy ones with fungicides. Root rot is another disease that occurs due to overwatering. For prevention and treatment, a potassium permanganate solution or biological preparations can be used.

Pests such as spider mites or pill bugs may also attack seedlings. Spider mites are often transferred from houseplants, so it is advisable to treat all indoor plants with insecticides before growing tomatoes. Pill bugs thrive in damp environments, so it is essential to ventilate the room thoroughly and apply appropriate treatments.