Do tomatoes need full sun – Complete answer

The question is: Do tomatoes need full sun? Well to start, light is a significant climatic parameter that influences tomato growth. Environmental factors influence the growth and performance of plants by affecting their physiology. Among the climatic factors, the most notable are temperature, light, CO2, and relative humidity.

In this blog, we will talk about the importance of light and how it affects tomato yield and answer Do tomatoes need full sun?

The tomato is a demanding vegetable in terms of the light that needs to develop. The requirement for light is especially high in the initial stages of the plant and also in vegetative development. In general, when conditions of optimal light exposure occur, the development of the plant and finally of the fruits is promoted, since light exposure allows a greater synthesis of red pigments such as anthocyanins and lycopene. There is a linear relationship between anthocyanin accumulation and light intensity, that is, the higher the light intensity, the higher the anthocyanin concentration.

On the other hand, very intense radiation can generate various problems, especially in the later stages of maturation. The cracking of fruits is the most common, it happens due to the increasing temperature in the layers of cells that cant support such pressure and finally crack. You can also have desiccation of the leaves due to increased evapotranspiration that will affect tissues and even end in necrosis (death of plant tissues) of leaves and shoots.

Let’s get into detail and the answer Do tomatoes need full sun?

Requirements according to the stage of the plant.

The light requirement that the tomato needs is at a maximum peak in the initial stages of the plant, that is, after germinating and during the first 20/25 days after emergence. If there is a lack of light in the first weeks of the tomato development, that can cause irreversible loss of yields, either due to lower production of leaves, which are responsible for the production of assimilates and energy for the plant and in later stages by generating fewer leaves or weaker leaves. This situation eventually could lead to more scattered flowers and result in lower weight and size of fruits formed. 

Sunlight is also important during vegetative development and fruit production, it is where we see that light availability must be maintained for at least 8 hours a day, if we do not achieve a minimum exposure of 8 hours, we must consider supplementing with artificial light. whether we are growing in a greenhouse or indoors.

A lack of proper light could also lead to a longer time required for maturation (which means longer exposure of the fruit to pests, diseases, physiopathies, etc.).

Do tomatoes need full sun

Sunlight During the Day

6 am to 10 am is the best time for tomato plants to receive the light they need as they provide high-intensity light to the tomato without the excessive heat of the midday sun.

Between 11 noon and 2 in the afternoon the sun’s rays can be too intense for tomato plants, the use of partial shadows is recommended as it will help reduce the intensity of the sun’s rays and thus prevent the plant suffer from stress.

The light that is received from 2 in the afternoon onwards depending on where you are can still be quite intense. However generally is less intense than the sunlight at midday, bringing the same benefits as the morning light.

Symptoms of Deficiency and Excess of Light

Tomatoes like all living species suffer from both malnutrition and indulgence. The lack of light in tomatoes usually results in less developed, but there are some early signs you can watch out for.

  • They do not grow or they do it slowly. If you notice that the plant is not growing as fast as it should the light could be the cause.
  • They bend and stretch abnormally looking for the sun
  • Stems get thinner and leaves start turning yellow.
  • The distance between the knots is lengthened (threading)
  • They do not emit flower buds or they fall or do not open and, consequently, do not fructify.

Neither does lack or excess of light favor the development of plants, these are some more common symptoms of excess that your plants might manifest if they are exposed to too much light:

  • They collapse, and they cannot synthesize more organic matter.
  • Dehydration deforms their bearing, as they tend to lean in the opposite direction to that of light.
  • The leaves lose their color, dry out, show brownish spots, and even burns that also affect could the fruit.

Both the excess and the defect of light, especially the first, can cause virus problems or favor the development of certain diseases.

Physiological disorders in tomatoes influenced by solar radiation

Physiological disorders are a series of anomalies in different plant structures, generally due to adverse climatic conditions, including low or high solar radiation interacting with other factors.

Below are some physiological disorders of tomatoes associated with solar radiation:

Split Fruits: They are caused by high solar radiation and high temperature, irregular irrigation, fluctuations in soil humidity and high air humidity, increasing if strong leaf pruning, and low levels of K, Ca, and Mg.

How to Prevent: Regular irrigation and controlled exposure of light are recommended.

Do tomatoes need full sun
Split Fruits

Spotted Ripening (clowning). It is favored by low temperatures in the greenhouse, low solar radiation, high cloudiness, and high relative humidity.

How to Prevent: Good air circulation if you are growing indoors and good light exposure.

Rolled Leaves. It occurs when the plant is subjected to extreme conditions of high or low temperatures and direct sunlight on the plant.

How to Prevent: This could be prevented by regulating the temperature, extreme oscillation is the main root of the problem plus too much sunlight. A half-shadow could is the solution.

Do tomatoes need full sun

Hollow fruits. They are caused by the excessive use of N, the low solar radiation, and the use of varieties sensitive to this disorder.

How to Prevent: this could be prevented by using resistant varieties and ensuring good sunlight exposure.

Stroke of sun. It is produced by direct exposure of the fruit to the sun’s rays, which generates a shiny and leathery white area, generally, it occurs when heavy pruning of leaves is carried out.

How to Prevent: be careful when pruning, cutting too many leaves could expose the fruit directly to the sun, and if you are not using shadows this problem almost guarantees that will appear. The fruit must be tucked in between the leaves.

Wrap Up – Do tomatoes need full sun

Tomatoes need full sunlight to grow but in a controlled manner. Exposing the plants to intense radiation could also bring some problems. as well as too low exposure will also carry consequences. Assuring 8 hours a day of light is recommended, preferably morning sunlight since it is of good quality and it does not have much intensity. The problems related to light are aggravated near the end of ripening, finally, be careful to prune the leaves too much this could expose the fruits to intense sunlight.