Citrus and Lemon Tree Leaves Yellowing | How To Treat and Prevent

How To Avoid Yellow Leaves on Citrus Trees

1. Ensure soil pH 6-8 for Citrus Trees

Soil testing can ensure that plants grow on good soil. Soil with pH 6-8 is the most ideal type to grow citrus trees.

Citrus trees with lower pH get yellow leaves due to magnesium deficiency. With this acidity in the soil, you have to use 10L water with 2 tablespoons of Epsom salt (magnesium sulfate) to water the plant. 

Dolomite can also address this problem with acidity. However, if you used calcareous soil, foliar feeding may be necessary. Alkaline soils have pH higher than six. This means that your plant is either deficient in iron or zinc.

When leaves become pale but have darker veins, they lack iron; when leaves become yellowish and pointed at the top, zinc is lacking.To address iron deficiency, apply chelated iron or use an iron fertilizer supplement. 

Meanwhile, spraying 2 tablespoons of zinc sulfate dissolved in 10L water can address zinc deficiency.

2. Supply Enough Nitrogen to Your Lemon Tree

Nitrogen deficiency manifests overall on yellowing leaves on a lemon tree. The discoloration may be random as nitrogen is a mobile macronutrient.

Usually, nitrogen transfers from old leaves to new ones to support new growth. As a result, older leaves tend to fall earlier and new ones tend to be more fragile than usual.

Nitrogen deficiency usually happens in the rainy season as water-logging is key culprit. This can easily be resolved in the dry season that comes afterward.

However, it may also stem from constant over watering with highly-porous soil, compacted soil, or root rotting. The practical way to resolve this is to give your plant just enough water and ensure that the soil fully absorbs the water. 

You can also resolve to spraying a low-biuret urea to the leaves to correct this.

Using the Correct Fertilizer to Keep Your Citrus Trees Healthy

Depending on the discoloration, the treatment and management for chlorosis varies. If the yellow-leaves symptom is showing on your adolescent plant, here are some ways to address it:

3. Know What Can Be Toxic to Citrus Trees

Citrus plants require specific amounts of different micronutrients like magnesium, iron, zinc, manganese, and boron. Though they are susceptible to micronutrient starvation, excesses can also lead to toxicity.

Yellowing leaves on a lemon tree accompanied by spotting is a sign of boron toxicity. To control the excessive boron levels in your plant, apply your nitrogen fertilizer as calcium nitrate.

Meanwhile, manganese toxicity manifests in bright yellow mottling, and sometimes tar spotting – brown scars on the leaves. You can lime the soil and repeat the process each year for up to four years to address this.

Citrus trees also cannot tolerate excessive salinity in soil. In particular, salt from manure or sodium chloride in soil or in water can turn citrus leaves yellow, create a burnt crust in the edges, and make the plant shed prematurely.

If you live near the sea, you might have to think twice about growing lemon or grapefruit.In hard water areas, high sodium content in softened water can be problematic, too.

So if you use a water softener, check the sodium content of the output water first

4. Don't Overwater Your Citrus Trees

Watering a citrus tree is quite tricky depending on the climate as water tends to drain slower in colder seasons. The plant only requires infrequent deep watering, but how do you know if enough is enough?

First off, know your soil. If your soil drains well then you don’t have to worry much, as long as you water it once it dries out completely. (In the summer, you can water once a week.)

The root of citrus trees is prone to root rotting or Phytophthora because some soil retain water for longer periods. Like chlorosis, root rotting also turns a citrus tree’s leaves yellow.

You have to ensure proper irrigation for your plant to avoid drowning it. The ideal water level for citrus trees is about two to three feet deep.

5. Adjust The Location of Your Lemon Tree

Autumn is the best season to plant citrus trees, while spring comes a close second. If you live in a tropical country or an area with warm climate, it is best to plant your citrus tree in a cool open area that receives plenty of sunlight.

Yellow leaves on citrus trees usually appear when temperature suddenly becomes warmer than usual.

Yellow bleached out spots appear on the leaves seasonally especially in the summer. This indicates sunburn but easily resolves itself when the weather improves.

Meanwhile, put your plants indoors during extremely cold climate as citrus cannot withstand severe frosts.