Asparagus ferns are common houseplants you’ll find in homes and offices because they are easy to care for and have few problems.
But if you notice your Asparagus Fern turning yellow instead of keeping its healthy green color, you’ll want to look at what’s causing it.
Why is your Asparagus Fern is turning yellow? The most common cause of Asparagus Fern turning yellow is overwatering or lack of light.
Other possible reasons include pests, fertilizer problems, underwatering, too much light and acclimate to a new environment.
It is important to identify the root cause of the issue in order to fix the problem.
Reasons for Asparagus Fern Turning Yellow
When your Asparagus Fern turns yellow, it means something is not right. Therefore, it is important to quickly diagnose and fix the problem before it turns into somethings worse.
However, because there are a few potential causes for yellow leaves on Asparagus fern, you’ll need to narrow down the potential culprits to make your diagnosis.
Here’s a list of the common reasons why Asparagus ferns turn yellow. For each, I’ll explain what is happening, why the leaves are turning yellow and how to fix each one.
Overwatering is a Common Cause Why Asparagus Ferns Turn Yellow
Overwatering is the number one cause for yellowing Asparagus Fern leaves. As such, I’ll spend a little more time explaining this problem.
Yellow leaves on your Asparagus Fern is one way the plant is telling you that something is wrong. Because the consequences of an overwatered plant is dire, it is the first thing you want to investigate when you see a plant turn yellow.
In most cases, overwatering is caused by a few reasons:
- Watering too frequently
- Using soil that is too heavy or retaining too much moisture
- The pot you’re using does not have sufficient drainage
- Not enough light or air circulation
Why Does Overwatering Cause an Asparagus Fern to Turn Yellow?
The roots of an Asparagus Fern need both water and oxygen to survive. Thus, it is important to provide a balance of air and water to keep the plant healthy and happy.
When you overwater the plant or water it too often, the soil becomes saturated with water. This is why and overwatered plant has wet, soggy and mucky soil.
The problem is, when there’s too much moisture, the liquid will clog all the air pockets in the soil. This leaves the roots submerged and swimming in water for long periods of time.
When this happens, the roots cannot get oxygen because of all the water. This causes them to eventually suffocate.
Too much suffocation leads to root damage or even root rot.
Once the roots rot or are damaged, they cease to be able to absorb water or nutrients from the soil. So, no matter how much you water the soil or add fertilizer, your plant won’t be able to get the hydration or nutrition anymore (since the roots don’t function properly anymore).
This results in a weak, malnourished, dehydrated plant with yellow leaves. For the most part, the lower leaves will turn yellow first.
But after a while, majority of your Asparagus fern will turn yellow as well.
How to Tell If Your Asparagus Fern is Turning Yellow Due to Overwatering?
If your Asparagus Fern is turning yellow, the first thing you should always check for is overwatering. Again, this is because of the serious consequences of too much water.
Here’s what to look out for:
- Wet, soggy soil – with overwatering, chances are the surface of the soil is wet, mucky or soggy. You can likewise stick your finger into the soil and it will feel like this as well.
- Check the size of your pot – one reason why I don’t recommend going with an overly large container when you repot is because you need a lot of soil to fill it. Once you water this large pot, the roots will find themselves swimming in too much water. Lots of water increases the risk of root rot because it takes much longer to dry.
- Your watering schedule – are you watering too often? This is usually the main reason for an overwatered plant. Asparagus fern need about 1-2 inches of water a week. In most cases, this is equivalent to watering once or twice a week depending on the weather. I find that the best way to tell when to water your plant is to wait until the top 1-2 inches of soil has dried before adding more water. But avoid letting the soil go completely dry.
- Light and temperature – both light and temperature both affect how quickly soil dries. The more sunlight the plant gets or the hotter the weather is, the faster the soil will dry. Thus, you’ll be watering your Asparagus Fern more often. However, if you keep the plant in low light or it is fall or winter when the temperature is cold, make sure to cut back on watering because it takes much longer for soil to dry.
How to Fix an Asparagus Fern Turning Yellow from Overwatering
Once you confirm that it is indeed overwatering that is causing your Asparagus Fern to turn yellow, the first thing to do is cut back on watering and allow the soil to dry.
I also like to check for root rot just to make sure.
To do so, unpot your plant and check the roots. Brush off any dirt so you can see the roots clearly. If you notice black, brown, mushy, soft or stinky roots, it means root rot has set in. Healthy roots should have a white color and a firm texture.
If there is root rot, it is more difficult to save your plant. And a lot will depend on how many healthy roots are left. The more healthy roots there are, the better the chance of survival.
The best way to try to save or revive your Asparagus Fern from root rot is to repot it I fresh, dry soil. Then give it proper care and hope it recovers. You’ll also need to prune the rotted roots.
If there is no root rot, all you need to do is allow the soil to dry. This will help the plant recover. Also review your current watering schedule to make sure that you don’t overwater the plant again.
Then cut off the yellow leaves. They will not turn green again. So, it is better to let the plant grow new, healthy leaves instead.
Low humidity is another reason why your Asparagus Fern is turning yellow can be humidity. It is important to note that lack of humidity can turn its leaves yellow, they’ll usually turn brown and crispy instead.
That said, it is worth spending a couple of minutes or so to check whether low humidity is causing the yellow leaves.
Asparagus Fern like humid environments. Ideally, it prefers humidity of 60% to 70%. Although it can tolerate lower humidity, try to maintain at least 50% humidity to avoid any leaf discoloration.
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Underwatering Can Also Be Why Your Asparagus Fern is Turning Yellow
In addition to overwatering, underwatering can also turn Asparagus leaves yellow. This happens when the soil becomes dry. In most cases, the soil will be very dry.
To check, feel the soil. You can touch the surface of the soil to see if it is dry. Or stick your finger into the soil.
Once leaves turn yellow, they will not recover and become green again even after you’ve solved the underly cause. Therefore, it is a good idea to prune them off.
However, pruning them off is only a cosmetic solution if you don’t address the underlying issue. Eventually, the leaves will turn yellow again.
The good news is that it is much easier to fix underwatering. Unlike overwatering, all you need to do here is to add moisture.
Do so by saturating the soil with water and then allow it to drain completely afterwards. This will let the roots get rehydrated.
To avoid an underwatered Asparagus Fern in the future, take note of how often you water. Also, it is a good idea to be aware of other environmental factors.
- The more light your plant gets, the faster the soil will dry
- Hot weather or high temperature will dry soil out much faster
- You need to water more often if humidity is low
- If your Asparagus Fern is pot bound, it will use up all the water very quickly
Low light is another potential cause of yellowing Asparagus Fern. When this happens, it is a sign that your plant is not getting sufficient light.
Like most houseplants, the Asparagus Fern needs medium to bright, indirect light indoors. Outdoors, it does well in partial shade.
The reason why light is very important is that plants depend on light for photosynthesis. Light is the raw material they collect which they later turn into sugars for energy.
Therefore, lack of light also means they have less energy to fuel their growth. As a result, you end up with an unhealthy looking, leggy plant. Additionally, your Asparagus Fern will grow slowly and its leaves will turn yellow.
All of this because it is not getting enough light.
The good news is that lack of light is very easy to fix. All you need to do is move the plant a brighter location. Once it gets sufficient lighting, it will recover on its own.
When choosing a spot for your plant, keep in mind that the amount and intensity of light are both important. And that light levels vary depending on the time of day and the time of year.
Therefore, you may need to move the plant away from too much sun during summer and towards more light during winter.
Too Much Bright Light
Another thing worth noting is that just like lack of light, too much light can turn your Asparagus Fern yellow. Sometimes it can turn it brown as well.
That’s because the plant cannot tolerate too much light.
Again, you need to take both the duration and intensity of light.
In general, Asparagus Ferns cannot tolerate more than 2 hours of direct sunlight each day. Outdoors, you want to avoid too much full sun as well.
When it gets too much intense light or for too long, it will turn yellow.
For this reason, it is important to find a balance between too much and too little light.
This is why an east or northeast facing window is usually the best spot for the plant indoors. It receives the morning sun which is much more gentle than that in the afternoon.
Asparagus Fern grow best when they get enough nutrients. As such fertilizer plays an important role in maintaining a healthy, happy Asparagus Fern.
Nutrient deficiency can cause yellow leaves in Asparagus Fern. Additionally, the plant will grow slowly and will look weak. Therefore, it is a good idea to provide it with enough plant food.
However, avoid the temptation of giving it more than it needs. Many growers apply too much fertilizer or apply too often in hopes that the extra nutrients will allow the plant to grow faster.
While this works in theory, it does more harm than good in reality.
That’s because fertilizers contain salts. These salts are used to transport the nutrients in order to make them easier for the plant to absorb.
After the plant has absorbed the nutrients, the salts become byproducts that accumulate in the soil.
The problem is that plants hate salts. And when too much fertilizer salt builds up in the soil, it becomes toxic to the plant.
Too much fertilizer will cause an Asparagus Fern to develop brown tips.
Thus, knowing when to apply and how much fertilizer to apply is essential.
For optimal results, give your Asparagus Fern a balanced, liquid fertilizer once every 4 weeks during its growing season. If you live in a tropical region, this will be all year round.
But if you live somewhere with cold weather, the growing season will only run from spring to summer. Avoid feeding the plant during winter as it won’t be growing much due to the cold weather.
Also, dilute the application to half strength.
Following these basic principles will help you avoid overfertilizing.
Yellow Asparagus Fern Leaves Can Be Caused by Cold Temperature
The Asparagus Fern enjoys warm, humid environments. Its ideal temperature is 65 to 80 degrees Fahrenheit. More importantly, it cannot tolerate temperatures below 55 degrees Fahrenheit.
Leaving it in a location that is too cold can cause it to develop yellow leaves.
As such, if you bring the plant outdoors, make sure to take it back inside once the weather gets colder towards the end of the year.
Indoors, avoid cold drafts and air conditioners as these can negatively affect the plant as well.
Asparagus Fern can experience pests just like any other houseplants. The most common bugs to attack it are spider mites, mealybugs and scale.
Unfortunately, because these pests suck on the plant’s sap, they will eventually cause its leaves to turn yellow.
That’s because they are robbing it of moisture and nutrients (which is what is in sap). In doing so, the plant eventually experiences nutrient deficiencies. And the signs will appear as yellow patches on the leaves.
As the pests grow in number and turn into an infestation, the yellow patches get bigger and will affect more leaves.
Therefore, it is very important to always inspect for pests. And when you spot any sign of pests, isolate the plant and start treatment. The earlier you spot the problem, the easier it is to fix.
The Plant Getting Used to a New Environment
The last reason for yellowing Asparagus Fern is acclimation. This is when you move the plant from one place to another.
In the process, the plant has to adjust to its new surroundings, which also has different lighting, humidity, temperature and other conditions.
In some cases, you’ll notice your Asparagus Fern turn yellow when you first bring it home from the nursery. That’s because the conditions there are optimized for plant growth.
The good news is, yellowing Asparagus Fern due to a change in its environment is only temporary. And the plant will resolve itself once its adjusts to its new surroundings.
Therefore, you don’t have to worry nor have to do anything if your Asparagus Fern turns yellow because of this.