What Do Yellow Leaves Mean: Common Causes

Al Ardh Alkhadra > Blog > Gardening > What Do Yellow Leaves Mean: Common Causes

yellow leaves

Are your houseplants suddenly turning yellower? Yellow leaves on your plants are usually by conditions that are not optimal for the plant’s growth.

It is easily identified in some plants when the cause is too obvious.

However, for other plants, it is not obvious, hence difficult to detect.

If your plants are slowly turning yellower, this article is for you.

Learn what can be the common causes behind your plants turning yellower.

yellow leaves causes`

Causes of Yellow Leaves

Normal Aging of Plants 

Aging is a natural process for plants too.

As the plant grows older, the lower leaves will change color becoming yellow or brown eventually.

It is the normal part of growth and aging.

Hence, it is nothing to fret about.

In fact, you can trim the main stem back so that there is new growth and business.

Whenever the plant becomes too leggy, you can simply trim it.

Moisture Stress Due to Over and Underwatering

Watering is one of the essential components of your plant.

However, it also needs to be the most balanced.

Overwatering and underwatering can both damage the plant easily.

In fact, they are one of the leading causes of yellow leaves.

You should know the water and moisture requirements of your plants beforehand.

Indoor plants may have different water and sunlight requirements than outdoor plants.

If the plant receives too much water it suffocates the roots.

They cannot breathe properly this they stop delivering the nutrients and water that plants require.

Since the roots cannot access nutrients and oxygen, the roots will begin to die.

This happens when the soil does not drain well and there is an overdose of water.

It can be hard to tell if the plant is getting too much water.

Especially in the case when it does not have drainage holes and you do not know about the soil’s ground makeup.

One way to see it is to check the soil before watering.

If it is moist, do not water it further, however, if it is dry then proceed with watering.

Also, it is important to water potted plants as much as the water they need.

Besides overwatering, underwatering can also harm a plant, turning its leaves yellow.

Let’s find out about that below!

underwatering plants

Underwatering and Insufficient Light

Not Watering Enough

Most people tend to water a plant when they see it is wilting and turning yellow.

While overwatering may also be a cause for that, underwatering results in plants dropping their leaves to conserve the water and prevent transpiration.

Right before they drop, the leaves turn yellow.

The yellowing of the leaves indicates that the plants need water.

You will notice the parched soil, their lack of growth, fallen leaves, and brittle, dry and droopy leaves.

Though, handling underwatering is easier than overwatering plants. More on that later!

Not Getting Enough Light

Water and sunlight both are crucial for a plant’s growth.

If a plant is not specifically one for a shade garden, it requires plentiful sun to photosynthesize and grow.

Scorching heat and sunlight can also damage the plant leaves sometimes.

Though when the soil is getting not enough light, the lower leaves will start to become yellow and then they drop.

The leaves that are yellowing from lack of sunlight will start to turn yellow on that side which is away from the light source.

Thus, the leaves that are near the window may be getting all the sun whereas those that are on the opposite end will start to turn yellow.

Indoor plants may be at a greater risk of yellow leaves due to a lack of sunlight.

Without enough light for photosynthesis, the leaves will turn sickly and leggy.

conditions of leaf

Lack of Nutrients and Compacted Roots

Some of the nutrients you provide to the soil are very mobile.

Nitrogen can easily leach as it moves around hence, resulting in nitrogen deficiency.

Moreover, there can be too much calcium in the water especially if you are using hard water.

The nutrients that are specifically deficient show up in various forms on the plant.

If not treated timely with fertilizers, the plants may die soon.

  • Magnesium deficiency shows yellow patches in between leaf veins and the yellowness moves from the center to outwards. The ledges become yellow last and it happens mostly in old leaves
  • Sulfur deficiency will turn new leaves yellow entirely
  • If there is general yellowing, it is hinting at Nitrogen deficiency. Older leaves turn yellow on the inside and then start becoming yellower on the outside too. Then it affects the newer, younger leaves too.
  • Iron deficiency will show up in the leaf veins becoming yellow, but it is more apparent on young leaves, hitting them before the old ones.
  • Potassium deficiency is when leaf edges turn yellow but insides remain green. It is more apparent in older leaves and their edges turn brown soon.

Root Damage 

Compacted roots and damage can occur because of gardening tools such as a wayward shovel, disease or root rot.

As the roots are damaged, they may not deliver sufficient nutrients to the plant and will not get enough oxygen.

One reason for that can be overwatering but also how plants outgrowing their container pots and compacted soil landscape can inhibit the flow of water, oxygen and nutrition movement.

Hence, the roots do not function properly and the leaves will turn from yellow to brown.

Other than that, disease, soil pH and cold draft can all turn the leaves yellower.

disease spreading on plants

Viral Infection, Pest Infestation and Soil’s Affect on Yellow Leaves

Disease and Infection 

Contaminated soil and pests can cause diseases in plants.

Moreover, viral, fungal and bacterial infections can be around store-bought plants and unsanitized garden tools.

Certain diseases that turn leaves yellow include black spot, mosaic virus, leaf spot and rust.

A viral infection may show up as blotchy patches on the leaves.

It will discolor flowers and deform leaves and stems.

Pest Infestation 

Houseplant pests such as mealybugs, aphids and mites can destroy the plant.

When they start to eat foliage then the plants become stressed and the leaves turn yellow.

They can also damage roots that will interfere with the oxygen, water and nutrient absorption through the roots.

Visible signs may not be in the first look, however, check under the underside of leaves to note any pest activity.

Soil pH 

An improper soil pH in landscape plants can influence the growth of the plants and affect their leaves.

Usually, when the soil is in a container with the plants its leaves will not turn yellow.

The pH of the soil affects nutrient uptake.

When the pH becomes lower or higher than a plant’s optimal range, it affects how plants access nutrients thereby impacting nutrient availability.

Even if you add fertilizer, it will be of no use as the uptake of nutrients is affected.

Hence, leaves will turn yellow until the issue resolves.

cold conditions

Cold Conditions

Cold drafts on tropical plants turn leaves yellow and they drop.

This is different from intense cold weather.

Exposure to that will turn the foliage brown and pale spots will appear in the veins.

Hence, if you place a temperature-sensitive plant near a vent or door, it causes yellowing and leaf drops.

A windowsill or air conditioner vent can affect the condition of leaves.

watering plants with yellow leaves

Solution For Yellow Leaves

For some plants, the damage may be irreparable, for others, you can take immediate measures to control the situation.

Normal Aging 

If the plant is too leggy, cut it back to the main stem.

This will promote new growth as it is already time for the old leaves to die.

The new growth will also be bushy.

Overwatering 

In this case, start by using well-draining soil for the garden and potted plants.

The container should always have drainage holes, add yourself if they don’t.

Know when the roots are rooting by smelling the plant. Is there a nasty odor? That’s your clue!

Also do not plant outdoors where the water tends to pool.

Underwatering 

Simply add more water.

Add mulch to outdoor plants around the dry area.

For the future, remain consistent in watering the plant.

Insufficient Light 

Move the plant closer to sunlight.

If the light in your home is not enough, think of using artificial grow lights instead.

Nutritional Deficiency 

If the soil lacks specific nutrients, using fertilizer is your answer.

Use a soil kit to test the needs of your soil and plant by performing a soil test.

It will identify the root cause to address it.

Damaged Roots 

Pull the Plant out of the container to look at the roots directly.

Repot if the roots are compacted.

Disease and Pests 

For pests, use pesticides like neem oil.

For diseases, contain the spread if it is viral.

Use fungicides and remove healthy parts of plants.

Soil pH 

Take a soil test and restore pH balance through soil amendments.

Cold Conditions 

Move plant to less turbulent area.

Find a warmer location instead.

Finally, 

Yellow leaves are harmful for your lush green plants.

Identify the cause behind it and treat it timely.

 

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