Seedlings turning yellow can be attributed to their natural growth cycle and possible issues with watering, light, soil and fertilization.Seedlings Turning Yellow

It can be worrisome, but fret not; in this article, we will dig deeper into understanding all the possible reasons why it’s happening, including how to solve each issue. Keep reading to learn more!

Why Are Seedlings Turning Yellow? 6 Common Causes

Six common causes of seedling turning yellow are that it is part of the natural growth cycle or overwatering. They will also turn yellow if there is not enough light or even too much light. Improper fertilization and poor soil quality are the other culprits.

– Natural Growth Cycle

If the yellow leaves on your seedlings are what are known as cotyledons, or the first leaves of a seedling, there is nothing to worry about. The cotyledons are intended to start the plant at the very beginning of its life; however, after it begins to produce additional leaves, these become less necessary and frequently turn yellow before eventually falling off.Causes of Seedlings Turning Yellow

– Overwatering

Overwatering is the most common reason why seedlings get yellow leaves. To ensure the growth of young plants, we frequently literally shower them with water, which leads to overwatering. It occurs very frequently, particularly when seedlings are placed in a small module tray where there is little margin for error and soggy modules are easily produced.

This causes the soil to lose oxygen, which causes the roots to drown. As a result, the roots will be vulnerable to rotting, as well as leaves turning yellow.

– Not Enough Light

If your seedlings are not receiving sufficient light, they will become leggy, tall, and spindly. The leaves will also change from light green to yellow. Ensuring that the plant has enough sunlight is among the crucial steps to having a healthy plant. You cannot expect your seedling to develop into a strong, green plant if it is kept in a dimly lit space.

– Too Much Light

On the other hand, if your seedlings are receiving excessive sunshine, it is also harmful. Seedlings exposed to too much sun will be sunburned and perish, often becoming yellow. Some seedlings also become stiff, waxy, and black, indicating that the light source may be too strong.

Plants also need downtime. A plant under stress from excessive light may develop leaf curls and even yellow leaves.

– Improper Fertilization

Yellow-colored leaves may indicate nutrient deficiencies as the seedling grows and begins to resemble a young plant. It is not necessary to provide nutrients to seedlings for the first few weeks, there should be sufficient nutrients for your seedlings to grow and develop between the nutrients in the seed and the nutrients in your potting soil mixture.

However, when leaves begin to yellow, it is easy to assume that there is a nutrient shortage and conclude that adding fertilizer is required. However, it should be noted that the yellowing of the leaves can also be the result of over fertilizing.

Your plants may potentially suffer more harm from overfertilizing. They can have stunted growth and be vulnerable to pests and diseases. In addition, excessive fertilization will burn the soil and choke the plants’ roots, which will stop them from growing.Solving Yellow Seedings Issue

– Poor Soil Quality

If the soil does not have adequate nutrients, the seedling leaves turning yellow and eventually perish. When the soil pH is between slightly acidic and neutral, most plants thrive; if it is excessively acidic or alkaline, however, your plants may struggle, and you may notice yellowing of the leaves.

Root damage can also occur in plants with improper soil. Compacted potting soil can stunt the root development of the plant and result in oxygen deficiency, compacted roots, and root rot. It can also retain too much water, which can cause damage to the roots and make the plants grow slowly.

What Can You Do to Prevent Your Seedlings’ Leaves Turning Yellow?

To prevent your seedlings’ leaves turning yellow you can firstly cut the yellow ones off. You should check your watering practice and use the by weight watering method. You can use a grow light if sunlight is not enough. Using good soil and fertilizing properly are your final steps.

– Cut off the Yellow Leaves

Whether the leaves that turned limp and yellow are cotyledons or true leaves, it is better to remove them since they are no longer doing the plant any good. Consistently pruning will assist the plant in efficiently directing the nutrients to the vital leaves rather than to the ones that are already dying, even at the seedling stage.

You can trim or cut the withering leaves at the base of their stems with a pair of pruning scissors. Given that cotyledons usually fall off on their own, you are just speeding up the process. By doing this, you are helping your plant use its energy to grow new, healthy leaves.

– Check Your Watering Practice

Make sure to dry out in between waterings to avoid overwatering. Any excess water should be drained, and the soil should not look wet. When watering seedlings, it is best to err on the side of caution and water them a bit too little rather than too much.

If you are underwatering your plants, they will appear drooping and floppy and may occasionally topple over, but as soon as you give them enough water, they will recover and immediately stand up again. In addition, keep in mind that a high-quality potting soil mix will improve drainage and reduce the likelihood of soggy or wet soil.Remedies for Seedlings Turning Yellow

– Use the Method of Watering by Weight

To do this, you need to have pots and potting soil mixtures of the same type. You should fill one pot with wet soil and another pot with dry potting soil. You should remember the difference in weight between the two, as this will be your reference when watering. It’s safe to water when your trays are lighter and the top layer of soil is beginning to dry off.

You need to check the weight of your module trays while they are dry and after you have watered them. It would give you an idea of whether you have been overwatering. It is not enough that the bottom trays are empty because the seed-starting mixture is like a sponge and can retain a lot of water, making the tray heavier than usual.

– Use Grow Light

Ideally, natural sunlight is sufficient for your plant’s growth, as you also need to give young plants at least eight hours of darkness each day. However, for those days and areas with not enough sunlight, you can opt to use artificial lighting, but use it with caution.

If you are using a bulb, you should put your plant two to three inches from the bulb and directly beneath the artificial light. Lighting exposure will depend on the needs of your particular type of plant, but usually, it ranges from twelve to sixteen hours per day. After that, you need to give your plant a break and put it somewhere dark for at least eight hours.Light for Growing Seedings

– Use Good Quality Soil

Sometimes, all it takes to revive a plant is a new layer of soil. The seedling is frequently not properly nourished by the starting soil. This can be avoided by using a high-quality soil mix for seeding.

– Fertilize Properly

Consider using fertilizer if you’re still having difficulties providing your plant with enough water and sunlight, but keep in mind not to use too much. When in doubt, it’s a good idea to fertilize seedlings every two to three weeks with a balanced liquid fertilizer.

In addition to being potted, fertilizer is needed if your plant’s true leaves are starting to turn yellow or you are suspecting that your plant has nitrogen deficiency. Pick an organic NPK fertilizer, but use caution; dilute it to 1/4 or 1/2 strength, and avoid fertilizing too frequently.


If you notice the yellowing leaves on your seedlings, it should not cause you to worry too much, especially now that you are better informed about the reasons and solutions. Let us summarize what we have learned:

  • The yellowing of your seedlings can simply be part of the natural growth process, especially if the yellow-colored leaves are forming toward the plant’s base.
  • Overwatering is the main cause of seedlings growing yellow-colored leaves. Always check your watering practice, and it is advisable to use the watering by weight method.
  • Both insufficient and excessive sunshine are harmful to your seedlings and may cause the yellowing of the leaves.
  • The yellowing of leaves can be due to nutrient deficiency, and adding fertilizers can encourage plant growth by supplying the soil with nutrients.
  • Regularly pruning and getting rid of the dying leaves can help your seedlings use their energy more efficiently.

Armed with the knowledge gained in this article, you can now confidently attend to your seedlings’ yellowing problems!

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