Why is My Foxtail Fern Turning Yellow? (And How to Fix)


There is no doubt that you aim to keep your plants healthy and striving. But what if your favorite foxtail fern is turning yellow?

As you read on, you will learn the necessary care procedures to maintain your plant’s shape and color.

Mostly, Foxtail ferns are turning yellow due to moisture stress and low water quality. Other possible causes are pest infestation, diseases, direct sunlight, lack of light, temperature, humidity, nutrient deficiency. In addition, too much fertilizer, and or inaccurate soil pH  can cause this issue.

Causes of Foxtail Ferns Turning Yellow

Moisture Stress

Overwatering is one of the common problems causing yellow leaves and stems. The Foxtail fern’s characteristics are similar to a succulent.

It has a taproot system where it stores water. That’s why frequent watering isn’t necessary except during drought or hot season.

When to Water the Foxtail Ferns

Water the plant whenever the top three inches of the soil is dry. The frequency depends on the season.

It could be once a week, once every three weeks, or every day. Just do the thumb or index finger test on the top of the soil.

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Water Quality

When watering plants, it is not only about how often you do it. You should also be keen on what you put to them.

The best types of water for houseplants are bottled spring water and rainwater.

The Best Water for Your Plants

Rainwater is the typical water used for gardening. Rainwater harvesting is a crucial activity for growers for plant irrigation. (Source: University of Massachusetts Amherst)

After testing the rainwater quality, the results said that it is generally soft with very few chemicals.

For vegetable growers, water treatment is essential. Nonetheless, watering ornamental plants with rainwater comes with several benefits. 

The tap water could be appropriate too, but it also depends on its quality. If it has too much chlorine, it might disrupt the plant’s growth. Tap water that comes from spring is an ideal option.

Chlorine has a benefit and one of the essential micronutrients. If your plant is only getting the right amount, there would be no major problem.

However, when there’s too much chlorine in the plant, it damages the plant’s tissues.

Once your plant absorbs the chlorine, it will eventually convert into chloride in the soil. That’s when you’ll notice the yellow spots and burnt leaves from your Foxtail.

Pest Infestation

When a Foxtail fern has pest infestation, the results will clearly show the plant’s droopiness or discoloration. Here are some Common Fern Pests:

● Fern Mites

This pest is challenging to recognize since it is small. The damage will only be visible when the damage is bigger than expected. It causes yellowing leaves and deformity.

● Nematodes

Nematodes are a small type of worm. They cause discoloring, stunting, wilting, and plants’ lesions since they also damage the roots underneath.

Mealy Bugs

You will notice mealybugs infesting your Foxtail fern when you see white waxy threads covering the pest.

Their typical meals are the joints in between the stems and leaves. If not controlled immediately, you will notice a yellowing leaf or stem.

The Natural Pest Controller

A study regarding the neem oil concluded that it could be a replacement for agricultural pest control. It has the essential components to inhibit the multiplication of pests. 

Diseases

Foxtail fern is not prone to diseases and pests, but anything could happen when not taken care of immediately.

Every plant comes with different soil and water requirements. For example, when you place the Foxtail near plants that need watering often, the fern might develop fungal disease.[1] 

Powdery mildew is also one of the common plant diseases. Your Foxtail fern is prone to fungal disease and powdery mildew if the place is too humid.

Foxtail Fern Fungal Disease Prevention

If you want to plant the Foxtail on the garden bed, make sure to place it together with other plants with similar requirements.

You can use baking soda as a fungistatic. Take note, however, that fungistatic is different from fungicidal. It only means baking soda is for fungi growth prevention rather than a fungi repellant.

But they continued that using baking soda prevents the fungal spores from spreading.

To avoid the accumulation of powdery mildew to your Foxtail, you can turn on the heater during nighttime when the humidity level is higher.

Direct Sunlight

Foxtail ferns grow best in bright light conditions, but too much heat and light can cause plants to turn yellow.

Where there is too much light, the leaf absorbs too much energy. As a result, the reaction centers within the chloroplast will have more damages.

When that happens, the leaves become paler, which leads to the yellowing of stems and leaves. Once they turn brown, it will eventually die.

When not taken care of immediately, the leaves will not only turn yellow, but also the plant could die.

Place Your Plant to Get a Favorable Light

Honestly, a Foxtail fern is easy to grow. It can even handle full sun in the morning.

However, beware that a hot afternoon sun can damage the stems and leaves.

Move it to a location where it can get the morning sun and afternoon shade.

Lack of Light

Light is the essential factor for a plant’s growth. The plants receive energy from the light to enable them to make foods to grow and strive. When that happens, they can produce starches, sugars, and substances.

Once your Foxtail fern is turning yellow, the first thing to look at is the location. Fern can grow indoors, but the quality is not the same as the one you put outdoors.

The leading cause of the yellowing fern could be the lack of light.

Ways to Supply Foxtail Fern the Adequate Amount of Light

Consider the Location 

Foxtail ferns strive best to the location where it gets the full morning sun and afternoon shade. Although this type of plant isn’t high maintenance, you need to be careful when choosing the perfect area.

Keep it away from the full scorching afternoon sun since it is harsh to the fern’s stems and leaves. 

Place the Foxtail fern across the window to get access to bright light.

Choose the Perfect Artificial Light for Indoor Gardening

The typical light sources used for plants indoors are fluorescent, incandescent, and light-emitting diodes.

Fluorescent tube, for example, is one of the best options since its most available types emit red and blue light.

The study confirmed that blue light is functional for regulating the stomata’s opening, responsible for controlling the water loss and the uptake of carbon dioxide. 

Temperature

The perfect temperature for foxtail fern is 65-70° F (18-21.° C). Too much heat or too much cold is not favorable for the plant.

Keeping it in the perfect location to get the full amount of morning sunlight will help it strive.

How to Save Your Plants from Harsh Temperature

Relocate Your Plant During Winter

The Winter season comes with a harsh temperature for a Foxtail fern. It is essential to relocate it to a warmer area to keep it from the freezing point. 

Covering the plants during freezing temperatures can cause significant damages to the plant. But as long as you protect the roots from freezing, it could recover by the time summer season arrives. 

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Protect Your Foxtail Fern from Heat Stress

If you already placed your plant at the perfect location, it receives minor damages during summer. Nevertheless, watering your fern frequently than your usual routine will prevent it from heat stress.

Moreover, watering the Foxtail up to 6 to 8-inch depth will make its roots more established deeper into the soil. It adds up to the plant’s vigor, capable of resisting harsh weather or temperature.

Humidity

Since Foxtail fern is a forest plant, that’s why a good percentage of humidity is crucial. The humidity level for Foxtail Fern should not exceed 40% to 50%.

Low Humidity Effect

When the humidity level is too low, the plant’s leaves water will disappear too quickly. The root will take up more moisture and will dry out the soil too quickly. So, they need more watering.

High Humidity Effect

Humidity causes moisture. If there’s too much plant moisture, that could lead to fungal diseases, such as Botrytis and powdery mildew.  

How to Fix Humidity Issue

Place your plant on the top of the wet pebbles for well-balanced moisture. If you decide to place the Foxtail indoors during dry winter, you can switch on the room humidifier, then set it on the cool-mist temperature.

The mentioned procedures can help to prevent the plant from drying out. Of course, place the plant indirectly from the humidifier where it blows hot and cold air.

Nutrient Deficiency

Here are some of the symptoms of nutrient-deficient plants that cause yellowing:  

● Yellowing of older leaves and the rest of the plant is light green (lack of Nitrogen)

● The leaves edge is turning yellow while leaving a green arrowhead shape in the leaf’s center part (lack of Magnesium)

● Yellowish younger leaves followed by older leaves (lack of Sulfur)

● Yellowing between the young leaves’ veins (lack of Iron)

● Causing a frizzle top with yellowing between the veins of young leaves (lack of Manganese)

● Yellowing older leaves from the plant’s bottom while the rest of the plant is lighter green (lack of Molybdenum)

● Yellowing between veins of young leaves (lack of Zinc)

(Source: University of Arizona Cooperative Extension)

How to Fix Nutrient Deficiency

Most nutrient deficiency in plants usually occurs due to a lack of nutrients found in soil. Organic materials come from the plant tissue and contain 60-90 percent moisture.

Other nutrients such as Magnesium, Calcium, Potassium, Phosphorus, Nitrogen, Sulphur, Hydrogen, Oxygen, and Carbon are present in the remaining dry matter.

The nutrients that appear from the plant residues could be fewer than the majorities’ viewpoint. But it has a significant impact on soil fertility to keep the plants healthy.   

Fertilizer Problem

Adding fertilizer to your plants from time to time will help your plants to strive.

However, take note that too much fertilizer—natural or chemical—could be harmful to your Foxtail ferns.

The Effect of Over-Fertilization on Foxtail Ferns

Over-fertilization can cause harm than good—which causes the yellowing of leaves and stems.

Although the plant will grow fast, an unestablished root system makes it challenging to supply the right water and nutrients.

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The Ideal Fertilizer for Foxtail Ferns

●  A Balanced Fertilizer (10-10-10)

A 10-10-10 fertilizer is the combination of 10 percent potassium, 10 percent phosphate, and 10 percent nitrogen. These three types of macro-nutrients are crucial for the plant’s growth.

Rich Organic Compost

You can skip the chemical fertilizer if you want an eco-friendly fertilizer for your plants.

You are not only helping the environment, but you are also keeping your plant’s roots established and healthy.

Soil pH

Most plant’s soil pH should be from 5.6 to 7.8. The University of Florida conducted a study for the Foxtail’s ferns requirement. Well-drained and alkaline soil will help the fast growth of the plants. 

A Foxtail doesn’t have a special requirement, but too much acidity or alkalinity of the soil harms your plant.

That’s when you will notice the yellowish leaves since the alkalinity or acidity disrupts their nutrient absorption. (Source : University of North Florida)

How to Fix It:

Soil Acidity

If the soil has too much acid, you can add more compost and organic materials to produce humus as they break down.

Alkaline Soil

The soil should have good drainage. Adding sulfur and peat moss adds acidity to the soil preventing water evaporation. Coffee grounds are also great alternatives for balancing the soil’s pH level.

Final Words 

Sometimes, having yellowish leaves and stems is not something to be worried about and is considered a natural occurrence to plants.

The truth is, some of your fern’s stems are going to die eventually, and that is normal.

All you have to do is remove the withered branches to keep the plant healthy and alive. Keep thriving and training your green thumb nature within.

Soon after that, you will keep your plants from further damages caused by the mentioned problems.

As you continue loving and taking care of your Foxtail fern, it will eventually show its vibrant shape and color.

Arifur Rahman

I'm the owner of gardenforindoor.com. After completing my bachelor of science in agriculture, I'm serving as a civil service officer at the Department of Agricultural Extension, Bangladesh. I started Garden For Indoor to make your indoor gardening journey easy and enjoyable.

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