Why Are My Hoya Leaves Turning Yellow? (And How to Fix It)


Indoor potted hoya leaves turning yellow

Leaves that are turning yellow often signifies that there is a problem. To help them, you have to know what causes this issue and how to fix it. This article will show you several reasons and countermeasures.

Hoya leaves turning yellow because of the incorrect amounts of light, water, and fertilizer. Wrong temperature, as well as low quality of water, can also harm the plant. Moreover, pest infestation and nutrient deficiency can leave yellow spots on the foliage of the Hoya plant. 

Causes of Hoya Leaves Turning Yellow

Sometimes, it can be difficult to determine why Hoya leaves are turning yellow. Do not worry, this article will help you by showing a number of common causes to look out for. You will also learn how to fix the issues. 

Light Exposure

Like all plants, Hoya needs light to engage in photosynthesis. Photosynthesis converts light, oxygen, and water into the energy needed by the plants to grow and bloom. Too much light or nothing at all can compromise the plant’s health. 

Avoid keeping your Hoya plant outdoors for a long time. Intensive and direct ultraviolet rays from the sun can scorch the plant. Prolonged sun exposure can even result in sunburn (brown and dry streaks) and make the plant limp. 

Likewise, do not place your Hoya plant in a dark area. Aside from photosynthesis inhibition, inadequate light interrupts chlorophyll production. Lack of chlorophyll results in yellowing because it is the green pigment in the leaves. 

How to Fix

To give your Hoya plant the appropriate amount of light it needs, here are a few tricks:

⦾Place the Hoya plant in an area that receives partial shade. You can put it in east- or west-facing windows. 

⦾If you put the Hoya plant outdoors, make sure it is not receiving direct light. Shade the plant with a cloth or a taller plant. 

Artificial lighting is a good alternative source of light. You can hang two regular fluorescent bulbs 10 to 12 inches above the highest part of the Hoya. Turn on the lights for four hours or more, depending on the brightness of the area. 

⦾If the plant got a sunburn, remove the affected part. This method will stop wasting nutrient supply to these hopeless leaves. And divert them to the growing ones instead. 

Improper Watering

Another common reason behind the yellowing of the Hoya leaves is improper watering. Do not underwater or overwater the plant as it can lead to problems. 

Do not let the Hoya plant sit in a drought-like environment, especially for a long time. Plants need water to move nutrients up to foliage and make food. Thus, an insufficient amount of water will make the leaves wilt, dry, and yellow. 

Meanwhile, an excessive amount of water reduces oxygen in the soil, damage, and even rot the roots. Plants with injured roots will not take up moisture from the soil. This incident further results in leaf discoloration, loss of vigor, and stunted growth of the plant. 

How to Fix

These tips will help you achieve the proper watering techniques for your plant:

⦾Water your Hoya plant only when the surface of the soil is completely dry. Check the soil moisture by lightly poking the growing medium or using a moisture meter. Around two or three inches from the topmost layer of the soil should dry out before watering again.

⦾Consider these several factors that influence plant watering:

  • Measurement of the plant – The larger plants need more water than the smaller ones.
  • Types of the pot – Plastic containers usually dry out more rapidly than the clay types.
  • Location of the plant – Moisture in soil under a bright environment tends to evaporate faster. 
  • Time of the Year – In cold months, plants require less frequent watering compared to the warm season. 

⦾Water the growing media several times if it is extremely dry. This method will rehydrate the soil that separates from the sides of the pot.

⦾Ensure proper drainage to avoid overwatering. Drill the base of the pot to make additional holes. Frequently pour off the collected water in a saucer at the bottom of the pot. 

Water Quality 

Proper watering techniques are not enough to make the Hoya plant thrive. They should also receive filtered water that is free of harmful chemicals. 

The effects of getting adverse substances will not show off overnight. It will eventually build up and accumulate over time. Sooner, you will notice yellow or dark spots in the leaves of the Hoya plant. 

The discoloration of the foliage happens because chemicals inhibit photosynthesis. Photosynthesis is a vital process for the plant because it is the way of making their food. 

How to Fix

Follow these methods to ensure that your Hoya Plant is receiving quality water:

⦾Hold back using tap water because chemicals such as fluorine naturally occur in it. 

⦾Let the water sit for a few days if tap water is all you have. This step will make some amount of chlorine evaporate.

⦾Water the plant with rainwater, melted snow, or distilled water. 

⦾Install a filtering system. It’s an investment for both the humans and plants that will last. 

⦾Give your plant lukewarm water. Extremely hot or cold might harm them. 

⦾Get your water a quality check by a local authority. This procedure will help you find out more about your water. Additionally, results will include information about the substances in your water. 

Incorrect Temperature 

A Hoya plant thrives well in an environment with temperature ranging from 68°F to 75°F (20°C to 24°C). Keeping them in a condition with extremes of temperatures can result in problems. (Source: University of Florida, IFAS Central Florida Research and Education CenterOpens in a new tab.)

A too high-temperature may cause some plant processes to malfunction. This includes rapid transpiration that can lead to water loss.

Meanwhile, severely cold temperatures can cause chill damage. Ice crystals form within the tissues of the leaves, expand and inhibit photosynthesis.

Both extremely cold and hot temperatures result in the reduced rooting, shallow growth, as well as yellowing of the leaves. 

How to Fix

Follow these methods to maintain the ideal temperature range for Hoya:

⦾Check if your Hoya plant is in a spot where temperature can drastically change. Places like windowsill are great for summer but get drafty in the cold season. 

⦾Increase warmth or coldness of the area using a cooling or ventilation device.

⦾Automatically regulate the temperature of the area using a thermostat. 

⦾Follow these procedures if your Hoya becomes cold-damaged (Source: University of Florida, Gardening SolutionsOpens in a new tab.):

  • Water the plant to defrost the soil and supply moisture to the injured plant.
  • Stop fertilizing for a while. Feed the plant again with fertilizer after the cold months. 
  • Do not prune the damaged parts. This affected foliage will help insulate the plant. 

Fertilizer Problem

While fertilizing your Hoya plant is beneficial, you might overdo it. 

Excessive amounts of fertilizer result in a build-up of excess minerals and salt. This formation alters the pH of the soil, making the nutrients less available to the plant. 

Moreover, too much fertilizer can lead to the sudden growth of the plant with poor root structure. It can even result in the toxicity that slows the development of the plant. 

Never overfertilize your plant as it can harm them and make the leaves yellow. Severe cases may even result in death. 

How to Fix

Here are a few methods you can follow to avoid overfertilizing your Hoya:

⦾As the Hoya plant grows, feed it with fertilizer two to three times a month. Liquid fertilizer with a 2:1:2 or 3:1:2 ratio is usually ideal for them. When it becomes established, go for high phosphorus fertilizer to encourage blooming. 

⦾Consider the soil volume and light intensity when feeding your houseplant. Both high light intensity and large pots require more fertilizer, otherwise less. 

⦾Here are a few ways you can follow if your Hoya Plant has symptoms of overfertilization:

  • Reduce the amount of fertilizer or stop feeding the Hoya Plant for a while until it recovers. 
  • Thoroughly water the soil several times to wash off excess salts. 
  • Ensure that the water drains out of the base of the pot when removing mineral formation.

Nutrient Deficiency 

Plants also suffer from malnutrition if they are not getting the appropriate amount of nutrients. The yellowing of the leaves is a result of low levels of certain nutrients. 

These nutrients include nitrogen, potassium, and magnesium. Stunted growth and deformation of the leaves are also indicators of nutrient deficiency.

Do not worry, the Hoya leaves can bring back its green appearance if it regains the nutrients loss. 

How to Fix

Follow these procedures to help your Hoya recover from nutrient deficiency:

⦾Give the Hoya plant sufficient amounts of water, light, and fertilizer. These factors are the main sources of the nutrients for the plant. 

⦾Get a soil test:

  • This test will help you determine what nutrients are too much or too little from your soil.
  • Results will also provide information regarding the pH level of the soil. The ideal pH level that makes nutrients most available to plants ranges from 5.5 to 7.0. It is also where good bacteria work best in the soil. You can use some products to adjust the pH level of your soil. 

⦾Check if the soil temperature is within the optimum range for nutrient uptake. A temperature ranging from 65°F to 75°F (18°C to 24°C) is ideal for most plants. To measure the temperature, get a typical thermometer and push it as deep as possible in the soil.

Pest Infestation

If you notice that the Hoya suddenly looks unhappy, you can suspect it is because of pests. Your plant may experience light to severe infestation of pests.

Watch out for some pests that love lurking at Hoya Plant. Insects like mealybugs, mites, and scales are usually from an infested plant brought inside the house. Meanwhile, aphids, moths, fungus gnats, and thrips fly from outdoor plants to the Hoya Plant. 

These insects suck the plant juices and secrete honeydew in the leaves. Honeydew is a sticky liquid that encourages mold production. The mold blocks the sunlight from entering leaves, thus inhibiting photosynthesis.

All these results in the wilting, drooping, and yellowing to browning of the leaves. Severe cases can also lead to stunted growth and even death of the plant. 

How to Fix

Solve the pest problems with these helpful procedures:

  1. Here are a few procedures you can follow to combat light infestation:

⦾Clean the leaves of the Hoya plant with a cotton ball dipped in alcohol. Wipe both the top and bottom part of the leaves. 

⦾Gently wash the leaves of the Hoya plant, Using a mixture of mild soap and water

⦾Manually handpick the insects. This only works for larger insects like mealybugs. 

  1. If the infestation is more serious and heavier, then here are things you should do:

⦾Remove the damaged parts by using a sharp shear or scissor. Disinfect the tool before and after pruning. 

⦾Spray the plant with appropriate insecticides. Make sure that the pot has proper drainage when doing this as phototoxicity Opens in a new tab.may occur. 

⦾Isolate the infected plant to prevent the spread of the pests to the nearby plants.

⦾Discard the Hoya plant if it is severely damaged and seems incurable. Burn or bury it deep down the soil. Do not put this plant in a compost pile. 

  1. Carefully examine the plant before purchasing it. Never bring an infested plant indoors. 
  2. Do not keep your Hoya Plant in stressful conditions. Overly wet soil under low light invites pests to breed. 
  3. Do a regular inspection of your plant. Make the checking of the plant after the watering session a habit so you will not forget it. This trick will help in preventing insects before they infest. 

FAQs

1. Why are Hoya leaves turning brown? 

Hoya leaves turn brown because of water-related issues. The incorrect amount and chemical accumulation from the water lead to this problem. Also, sunburn, pest infestation, and diseases can leave brown spots in the foliage of the plant. 

2. Why are my Hoya leaves falling off? 

The primary reason behind Hoya leaves falling off is root rot. A damaged root will no longer supply nutrients and moisture from the soil up to the plant. Thus, leaves will wilt and fall off. Do not overwater and ensure proper drainage to avoid this. 

3. Why are my Hoya leaves shriveling? 

The leaves of Hoya shrivel because it is not receiving a sufficient amount of moisture. Water the plant or increase the humidity of the environment. Additionally, assess the condition of the roots if it is dry, damaged, or rotten.

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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