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Lettuce Leaves Turning Yellow: Causes and Solutions Explained

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It can be discouraging to see your lettuce plant’s leaves turn yellow. Just what causes the turning of a lettuce plant’s leaves yellow? 

Lettuce needs at least six hours of sunlight a day and should be watered regularly.

Being a leafy green, lettuce will thrive in a nitrogen-rich environment and will turn yellow if there is a nitrogen deficiency present. Water-logged soil and excessive sunlight can also lead to the yellowing of leaves as the bleaching effect of sunlight can cause the leaves to go pale and wilt, coupled with too much water intake.

There are a few other factors that can lead to the yellowing of lettuce which we will discuss further in this article, as well as the corrective actions you can take to stop or prevent the yellowing of lettuce leaves.

Lettuce Leaves are Turning Yellow:

Lettuce Leaves Turning Yellow

Before getting into what causes lettuce to turn yellow, it’s important to know that there are different types of lettuce plants: loose leaf and Romaine. 

Loose leaves are just as they sound: they grow their greens in a loose arrangement on top of the soil. Romaine lettuce, however, is grown to develop a central mass of leaves.

Loose leaf lettuce is more susceptible to turning yellow than its counterpart because it grows in a looser shape. Lettuce plants grow best when they have room to spread out and soak up sunlight from all angles. 

When this doesn’t happen, the leaves can start to yellow and become malnourished. This yellowing may also occur if you plant them too closely together or forget to thin them out when they’re small enough.

If you notice your loose-leaf lettuce starting to turn yellow, try adding more fertilizer or moving the plant so that it has more space to grow.

I have had the best results from using Miracle-Gro Soluble fertilizer. It’s great value for money and will last a long time. Just apply to the lettuces twice per week when watering as foliar spray. You can find it by clicking here.

Miracle-Gro 1001233 Water Soluble

What Causes Lettuce Plants to Turn Yellow?

When a lettuce plant turns yellow, it means that its basic needs have not been met: it hasn’t been given enough light, water, or nutrients. Here are some ways that this happens:

Nutrient Deficiencies

You can expect to see yellowing leaves when a nutrient deficiency occurs in your lettuce plants, whether they be Romaine, Iceberg, or any other variety.

The yellowing may appear around the edges of the leaves first, with the rest of the leaves following suit over time.

A nitrogen deficiency usually causes this problem, the plant doesn’t have enough nutrients (primarily nitrogen).

Watering Too Much

It may be getting too much water. Lettuce plants need plenty of water, but they also need air circulating around their roots in order to get their proper nutrients.

If you’re overwatering your lettuce plants, it can lead to root rot and then yellowing of the leaves. 

Make sure you’re watering enough to have the soil moist, but not soaking wet, and that there is enough space between the plant and its pot so that the roots aren’t sitting in water or sitting in excess soil that hasn’t been properly drained.

Keep an eye on the soil for signs of moisture and you should be able to avoid yellow leaves in lettuce plants in no time!

The Fungus Can Also Cause Yellowing in Lettuce Leaves

Yellowing could be caused by bugs or disease; check under the leaves for signs of trouble like aphids or other insects, or white spots from mold or mildew. 

If you have an infestation, remove the affected lettuce and wash your plants with warm water to eliminate any bugs that may be clinging there.


Too little light can cause yellowing leaves as well as overall weak growth in lettuce plants. Some plants need to be placed in a room with natural sunlight while others can be placed under artificial lights. 

Lettuce prefers six to eight hours of sunlight a day, and if your plant isn’t getting that much sunlight, it will start turning yellow.

How to Prevent Yellow Leaves In Lettuce Plants?

As a gardener or plant lover, you must pay extra attention to your lettuce plants for getting yellow leaves. You can prevent this problem by following the simple rules given below:

Maintain the Right Temperature and Light

If there isn’t enough sun or shade for your plants where they are now, try planting them somewhere else in the yard that gets more sunlight, in full sunlight (6+ hours a day), lettuces should be fine even with less frequent watering.

Check the pH Levels

It’s important to check the ph levels of your soil before planting lettuce to ensure that the soil has enough phosphorus to support the growth of your plants.

The ideal ph level for soil used to grow vegetables like lettuce or potatoes should be between 6-7.

Add Fertilizer

If you think that you’re seeing signs of a nutrient deficiency in your lettuce plants, add some fertilizer to your garden bed before watering.

Just don’t wait too long to do this, the longer you go without adding fertilizer, the more likely it is for your lettuce plants to suffer from nutrient deficiency.


Sometimes when things go wrong, it’s not you’re fault! This article discusses the causes of yellowing lettuce leaves and treatment options.

Knowing why your lettuce is turning yellow can help you fix the problem. Over or under-fertilizing will cause a plant’s leaves to turn yellow. If you take care of your lettuce, it will stay healthy!

Frequently Asked Questions About Lettuce

How Often Do I Have to Water Lettuce?

2 liters of water per day. But it’s better to pour this amount over several times on one day of the week than regularly every day. Otherwise, about half of the water evaporates via the soil surface.

When and How Often to Fertilize Your Lettuce?

Lettuce should be fertilized regularly. generally, you should fertilize with some liquid fertilizer two weeks after planting the seedlings, and then every few days until the seedlings are about four inches tall.

What To Do If the Lettuce Shoots?

In principle, lettuce is still edible and non-toxic, but the leaves often become tough and bitter during the shooting, so they no longer taste good. The plant stores bitter substances in order to become less appetizing for predators.

What Does Lettuce Need to Grow?

Lettuce plants need a location that is as sunny as possible. This is especially important if you not only grow lettuce in the summer but also want to plant salt in the fall so that you can also harvest in the winter. In addition, you avoid high nitrate levels with a location in full sun.

Where Does Lettuce Grow Best?

A location in full sun is an absolute prerequisite for lettuce – especially for successful cultivation in spring and autumn – in order to avoid high nitrate levels. The lettuce also needs deep and humus-rich soil.

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