Is Light Bad for Plant Roots? What you should know

When repotting or if the plant is grown in water culture, the roots of the plant may be exposed to light. Growing new plants often involves the method of water propagation, and root exposure to light might be problematic.

Plants need light in order to produce food that will result in both healthy growth for the plant and the roots and has no effect on plant roots. As a result of algae growth on the surface brought on by excessive sun exposure, roots may turn green. The roots can be shaded to slow the formation of algae.

In hydroponic systems, light can encourage the growth of both algae and mold. Please refer to our in-depth article on the causes of green plant roots.

We go over how plant roots can be exposed to light in this post, what to expect when there is too much light, and what you can do about it.

Does Light Affect Plant Roots

Plant roots are impacted by light. By absorbing energy from the upper portions of the plant, light promotes root growth by providing sugar and auxin, especially to the young roots. In other words, light can have a beneficial impact on root growth.

Only when the entire plant is darkened can light have an impact on root growth. Here, the plant and its roots will grow more slowly due to the lack of light.

However, certain plants can survive in low-light environments.

Here are a few examples of plants that can survive in low light:

  • Dracaena
  • Asian evergreen
  • Bromeliad
  • Vegetable spider
  • Viper plant

In-depth information on plants and their light requirements may be found in our page on how long a plant can go without light.

As a result of excessive moisture loss, too much light will raise the temperature of the plant and may cause the leaves to dry out. When it comes to root development, light intensity also matters.

While the rest of the plant grows in the direction of the light, the roots move away from it toward the dark earth to anchor the plant and ensure that it can receive water and mineral nutrients.

Due to the soil’s high absorption, light can only travel a few millimeters beneath the surface.

Even if they are exposed on top of the earth, shallow roots are not impacted by light.

You can apply this high-performance, water-based rooting gel from Amazon if your roots exhibit signs of damage. Root growth is encouraged by the whole spectrum of mineral nutrients included in it. Clicking here will take you there.

How can Roots become Exposed to Light?

Erosion caused by environmental factors such as temperature changes, torrential rain, and wind can result in the light exposure of soil roots.

In potted plants, sinking soil will also expose roots to light as organic debris decomposes.

You can read our in-depth article on what causes soil to sink and how to correct it while still safeguarding plant roots.

We’ll start by examining how repotting might expose roots to light.

During Repotting

When your plants have become root-bound and are merely sitting there, unable to grow, transplanting or repotting becomes necessary.

The roots might be exposed to light and air while being transplanted. Since direct light does not influence the root system, air is the key issue rather than light.

Mold and algae growth are brought on by air exposure. The problem with root development is brought on by the algae and mold.

Through Glass Planters

Glass jars expose the plants and their roots to light, but because roots are made for anchoring and sifting through the soil in search of water, they stay buried in the ground.

This explains why the roots appear to be invisible to the eye in clear or glass containers.

With success, I have repurposed glass candle jars to cultivate succulents. While some roots are exposed to light as it goes through the glass, neither the plant nor the roots are harmed.

Root bound plants

When a plant is root-bound, the earth underneath it appears to be overrun by roots.

Since these roots gather beneath the earth, they are probably exposed to the light because light can travel several centimeters below the soil’s surface.

In other instances, the root-bound plants’ apical area contains sensory cells.

Aerial roots

Aerial roots, also referred to as air roots or breathing roots, hang from trees, therefore exposure to light is inevitable.

They perform photosynthesis, thus it makes natural that they would be exposed to dappled light as they develop.

How to Ensure Roots are not Exposed to Light

The most popular method for shielding roots from light is to use dark containers.

The black spots are the finest to utilize to keep the roots from being exposed to sunlight because they block out sunlight completely.

To supply energy for root initiation and development, cuttings, especially vegetative cuttings, need to be exposed to light for a minimum amount of time.

Over time, the soil in potted plants has a propensity to sink. This is a result of the soil’s organic materials decomposing. Some roots may consequently become visible near the surface.

To remedy this, simply add more dirt and cover the roots with a nourishing potting mix.

My plants stay healthy even after repotting thanks to the Miracle-Gro Potting Mix I get from Amazon. Clicking here will take you there.

Do Hydroponic and Aquaponic Roots need Darkness?

We are well aware that roots always expand and bend to block light. Instead, they seek obscurity and flee from light. Aquaponic and hydroponic roots also do this.

Although they can be exposed to some light, the roots of hydroponic and aquaponic plants do not require light.

Even though too much light may not damage the roots, it might cause algae to grow on the roots, which can give them a chlorophyll-green colour.

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