Asparagus ferns (Asparagus setaceus) are renowned for their lush, bushy appearance, making them a favorite choice for both indoor and outdoor settings. However, sometimes these lovely plants can grow leggy due to less-than-ideal conditions.
To encourage bushier growth in your asparagus fern, prune bare stems, improve sunlight exposure, establish a watering routine, and provide summer fertilization, along with maintaining high temperature and humidity levels.
In this article, I’ll discuss the common reasons behind asparagus ferns turning leggy and provide you with practical solutions. Let’s dive right in.
1. Prune Your Asparagus Fern Sporadically
Sporadic pruning is the best way to keep asparagus ferns looking bushy. Most people make the mistake of thinking that they need to constantly prune their asparagus ferns to keep them looking good. However, this actually inhibits growth and makes the plant less bushy.
Generally, you should only prune your asparagus ferns every few months to give them time to grow and fill out, resulting in a fuller, healthier plant. When pruning, be sure to remove any dead or yellowing leaves.
You should also cut back any long, leggy stems to encourage new growth and keep your asparagus ferns looking their best.
Bare Stems May Need Pruning
Bare, elongated stems that lack substantial growth stand out from the rest of the plant, giving it that undesirable “leggy” look.
Removing bare stems is simple.
Using scissors or a sharp knife gives the best results, but you can probably get away with simply pinching off the undesired stems with your fingers, as they’re pretty thin. Either way, you should wear gloves. Asparagus ferns have tiny prickles that, while not very sharp, can be a painful inconvenience if you’re barehanded.
Pro tip: Sanitize the knife/pair of scissors before getting to work if you use the tool for pruning other plants in your collection to prevent spreading unwanted infections or diseases.
Once you’re done removing the bare stems, you’ll notice that your asparagus fern looks bushier. Now you’ll want to cut off the tips of all the individual stems, even the ones with a lot of foliage. Doing that will encourage your fern to grow more foliage.
It’s best to do this individually or with a few at once because you don’t want to cut too deep.
Remember, you’re only cutting off the tips, or the first couple of inches, of each stem in this case. Cutting too much of the stem is counterproductive to your goal as it’ll only increase the amount of green matter your fern has to regrow.
This process may take some time, but with a little dexterity, you could be done in as little as a few minutes. You’ll have a trimmed, slightly smaller version of your asparagus fern, but one primed for future growth.
If you’re worried about hurting your plant, don’t be. As long as you don’t go overboard with the cutting, you’ll see now and denser growth within weeks.
Cutting From the Tips Is Key
Occasional cutting from the tips can make your asparagus ferns bushy. When you do this, new growth will emerge from the center of the plant, creating a fuller, more compact appearance.
As an added bonus, regular pruning will keep your asparagus ferns healthy and free of pests and diseases. To get started, remove the top inch (2.5 cm) of growth from some taller stems, careful not to damage the underlying leaves.
2. Make Sure Your Fern Receives Enough Sunlight
Pruning might make your fern bushier in the short term, but you’ll have to address the root cause of the issue if you want more long-term effects. The primary reason for asparagus ferns not growing as bushy as they should be is a lack of sunlight.
Asparagus ferns don’t need bright light to stay healthy and can thrive in moderate to low light conditions indoors. However, plenty of sunlight will make them appear bushier. So if your plants don’t get enough sunlight, they won’t be able to maintain their bushy appearance. If they can’t get adequate sunlight, they’ll adapt by growing longer, which is something we commonly see in nature.
Plants that don’t get their fair share of sunlight grow longer and taller to reach sunlight. You’ll have to supply your asparagus fern with indirect or filtered sunlight, or you can leave it out for a few hours during the early morning.
Asparagus ferns are evergreen, meaning they keep their foliage year-round and are often used as houseplants because they tolerate low-light conditions well. However, if you want your asparagus fern to be bushy and full, it’s important to give it proper sunlight, as brighter light can encourage more lush foliage.
Indoors, if possible, place your pot about 5 feet (1.5 m) from an eastern window for moderate light in the morning. Rotate your plant by 90-180° every time you water it to ensure all sides receive adequate light.
If you want to keep the plant in a darker room or office for decoration, you can use a grow light to compensate. Not only are these lights great at what they do, but you also won’t have to worry about incurring damage from exposure to intense sun rays.
You can look for grow lights rich in blue light because they’re more effective in keeping plants more compact and bushy. Aim for a grow light with intensity ranging from 200-500 foot candles, and place it directly above your asparagus ferns (at least 12 inches or 30 cm away) for even growth.
Pro tip: Give your ferns six hours of exposure to grow lights or 4-6 hours under filtered natural sunlight.
Avoid the Afternoon Sun
Asparagus ferns like to be in the sun but don’t appreciate direct afternoon sunlight, as the hot sun will dry out the foliage. Move your asparagus fern into a shadier spot in the afternoon when the temperatures get too high.
You can grow your asparagus ferns in a slightly shady part of your garden if you don’t have time to move them around during the day. However, avoid deep shade as it can cause them to become leggy and sparse over time.
Choose a location that’ll provide your plant with adequate morning light but receive shade from the harsh afternoon sun. For instance, try placing them close to the wall in your east-facing garden, as this will ensure that the foliage stays lush and bushy all year round.
3. Fertilize During the Growing Summer Months
The amount of nutrients in the soil greatly determines how fast your asparagus fern can grow. So ideally, you should grow your ferns in nutrient-rich soil when planting them. However, nutrients in the soil slowly deplete over time.
Fertilization isn’t necessary for all plants, but it certainly does help them grow faster. You can usually make your own fertilizer at home using degradable matter, but water-soluble, all-purpose fertilizer works better for asparagus ferns.
They aren’t as nutrient-hungry as most other plants, so going overboard is a real issue, as too many nutrients in the soil can be detrimental to these plants’ health. This is precisely why you should dilute the fertilizer to half-strength before adding it to the soil.
You’ll also want to fertilize during the summer months only, which is when the fern grows fastest and needs the most resources to keep up the pace. It falls dormant during the winter, which is why fertilization is not advised during the colder months of the year.
If you want your asparagus ferns to thrive, fertilization is one of the most important steps, but what’s the best way to go about it?
Choose the Right Fertilizer
The key to successfully fertilizing your asparagus ferns is using the right fertilizer, so you’ll want to choose one with a balanced ratio of nitrogen (N), phosphorus (P), and potassium (K).
Aim for an NPK ratio of 10-10-10 to ensure that your plants receive all the nutrients they need for healthy growth.
It’s also important to choose a fertilizer formulated specifically for flowering plants like asparagus ferns. This fertilizer is designed to help promote flowering and foliage growth while keeping pH levels balanced.
Observe Proper Timing When Applying Fertilizer
When it comes to fertilizing your asparagus ferns, timing matters. Spring is generally the best time of year because this is when new growth begins and older leaves begin to die off.
At this time, apply a slow-release fertilizer according to package instructions every six weeks until summer arrives. Once hot weather hits, switch over to a liquid or water-soluble fertilizer and apply it every four weeks instead. It will keep your plants hydrated during warmer temperatures.
Be Careful With Over-Fertilization
Fertilizing too often can be just as bad as not fertilizing enough. Too much nitrogen can cause leaf burn, which could lead to leaf loss or stunted growth in some cases.
To avoid this issue, be sure to stick with the recommended dosage and frequency on the package instructions for whichever fertilizer you choose and never exceed it. It’s sometimes even better to apply fertilizers at half-strength.
4. Water Regularly and Generously
Underwatering and overwatering present their own issues, so finding the “sweet spot” in terms of the watering frequency and quantity is crucial. The problem is, knowing exactly how much water your asparagus fern needs isn’t so cut and dry, especially if you’re growing one in a hanging basket.
A tailored watering routine is best done early on if you want to see your fern thrive.
Asparagus ferns don’t need to stay hydrated as much as the average houseplant. They have tuberous roots that can store moisture. Nevertheless, they don’t like drying out either.
The frequency with which you need to water your asparagus ferns will vary based on the time of the year. Naturally, you’ll have to water more frequently in the hotter months as the soil dries out more quickly.
You’ll need to be precise with your watering routine during the summer because high temperatures increase the plant’s water demands. You can take a break in the winter, though, as they have dramatically reduced water requirements during their dormancy.
Either way, avoid overwatering because the low to moderate light requirement of asparagus ferns means that there’s not enough light and heat energy to draw moisture out of the soil.
You can find out more about how much water ferns in my other article: How Often Should You Water Ferns in a Hanging Basket. This guide covers formulating watering routines in greater detail and highlights the best practices for watering them.
Asparagus ferns need regular watering but should never be sitting in puddles of water or overly saturated soil, which can lead to root rot and other problems. Instead, you should water your plants deeply and thoroughly about once or twice a week during the summer months when temperatures are higher.
When winter comes around, you can scale back on watering to about once every two weeks or so. Just make sure that you keep an eye out for any sign of wilting or browning leaves.
Determining Soil Moisture
Asparagus ferns grow best in soil that is consistently moist but never soggy. An easy way to know that your fern needs more water is by sticking your finger to check the moisture. Smaller pots can hold less moisture than larger pots so the requirement can vary depending on the size of your plant.
For pots between 6 and 8 inches (15-20 cm) deep, check up to 1 inch (2.5 cm) below the soil surface. For larger pots, check about 2 inches (5.1 cm) deep into the soil. Be careful when digging into the soil as you might damage the roots. You can use a chopstick as an alternative but be careful when digging it in.
If the soil is dry, go ahead and water generously, but if it’s still wet, wait another day or two. Having moisture-retaining soil rich in organic matter really helps when growing this plant.
Ensure you water until the excess runs out from the bottom of the pot to ensure that all of the roots get enough moisture. Avoid overwatering by only giving them enough water each time and checking for signs of saturation before adding more.
Best Water Type
Asparagus ferns prefer filtered water over tap water. Since they grow in tropical climates naturally, they don’t do well with too much chlorine or mineral deposits found in most municipal water sources.
If possible, use rainwater or distilled water for optimal results. It will prevent unwanted salts from collecting in the soil, which can cause nutrient deficiencies and difficulty absorbing water from the soil over time.
5. Maintain Average Humidity in the Growing Area
Asparagus ferns love humidity but don’t require high levels compared with other houseplants. Keeping an indoor humidity level around 50% is often enough for asparagus ferns as long as the soil remains moist.
Still, dry and arid spells during summer and cold, dry winters can leave them in an unpleasant and suboptimal setting.
A more hands-off way to keep your asparagus fern humid during arid conditions is by placing it in a room with a humidifier. Humidifiers are quite effective at increasing humidity, but they can cost a fair bit of money.
No worries, though, if you don’t have a humidifier. You can keep your ferns comfortable during dry spells by misting them daily. Try to get the entirety of the plant in each session, especially the longer stems, because they lose water faster.
6. Mist the Asparagus Fern Regularly
Misting is one of the best and low-cost methods for keeping your plant happy and healthy. Asparagus ferns need moderate amounts of moisture in the air to remain bushy.
Although they don’t require as much humidity as their tropical relatives, comfortable indoor humidity in more extreme climates may be too low for them. Misting your asparagus fern can provide the necessary humidity to the plant, albeit briefly.
Low humidity can cause their leaves to dry or brown or even die if left unchecked. Misting them with water on dry days can help them perk up.
How to Mist Your Fern
The best time to mist your asparagus fern is in the morning when temperatures are cooler during days when you don’t water the plant.
You should use lukewarm water that has been filtered or distilled because tap water often contains chlorine which can damage the leaves of your plant over time.
Distribute water evenly throughout the entire plant without saturating any area too heavily. It’s also important to ensure that all excess water is removed from the pot after misting, so it doesn’t cause root rot.
Misting can be done daily, a few days after watering, depending on how dry it gets in your home and how quickly the soil dries out between watering.
Alternatives to Misting
Even the most meticulous gardeners can sometimes fall victim to environmental troubles that affect plants, such as pests and microbial infections. Misting your asparagus fern can be beneficial to briefly raise the humidity around your plant.
However, doing this frequently also means creating a conducive environment for pests and fungi to proliferate. Pests like mealybugs and aphids can invade your plant, especially when you’re growing it near other houseplants which may have been infested prior.
Mold or other fungi and bacteria can also lurk in your home and are just waiting for an opportunity to land on your plants and damage them.
In that case, you can employ other low-cost methods to improve the humidity around your plants, such as:
- Grouping houseplants with similar light, temperature, and humidity needs (ensure they’re free from pests or diseases)
- Placing your pot over a pebbled tray with shallow water (keeping the drainage hole safely above the water line)
7. Raise the Temperatures in Your Growing Area
Just like humidity, asparagus ferns prefer higher temperatures. They can’t survive very long once temperatures drop below 55 °F (12.7 °C), let alone freezing. If temperatures drop below this point, bring ferns growing outdoors back inside.
To ensure your Asparagus Ferns stay in good health, you want to keep them near room temperature, around 77 °F (25 °C).
8. Protect From Frost
Asparagus ferns naturally grow in tropical and subtropical climates, where temperatures never drop below freezing.
When these plants are exposed to temperatures below freezing, the foliage will die off and become sparse. To keep your asparagus fern looking full and lush, you must ensure it’s protected from frost.
How to Protect Your Plant From Frost
The best way to protect your asparagus fern from frost is by moving it indoors before temperatures drop below freezing outside.
Make sure you move it into a spot with plenty of natural light but be careful not to overexpose it. Asparagus ferns prefer indirect light for best results.
In addition, make sure that you are watering your asparagus fern regularly during the winter months. However, avoid overwatering it.
Due to low temperatures and poor air circulation indoors, your potting mix will dry out more slowly, so adjust your watering routine accordingly. Too much water can lead to root rot and other issues affecting your plant’s health.
9. Repot for More Growth
Repotting your asparagus fern is the perfect way to get it back into shape and create an even bushier look.
Choose Your Container
When repotting an asparagus fern, it’s important to choose the right container for the job.
You want a container that’s wide enough so that all of the roots can fit comfortably in the pot but not too deep, or else the fern may grow downwards instead of outwards.
Asparagus ferns don’t grow fast and regular pruning can keep the foliage and roots compact. That said, you can go for a pot that’s one size larger or 1-2 inches (2.5-5 cm) wider and deeper than the original pot.
Ensure the material is porous, like terracotta, and that there’s a drainage hole at the bottom so that water can drain properly from the soil.
Prepare Your Soil
One of the most important factors in growing asparagus ferns is choosing the right soil so that your ferns thrive and stay healthy.
Asparagus ferns aren’t picky regarding soil and will do well in any nutrient-rich potting mix. But if you want your plants to thrive, use good quality compost or organic matter, such as peat moss or coconut coir mixed with perlite or sand, for improved drainage and aeration.
Make sure that the pH level of your soil is between 6.5 and 7, as any higher or lower than this range may cause the roots to rot, leading to other problems like leaf discoloration or root death.
The best substrate for asparagus ferns would be loamy soil, which will retain moisture and provide nutrients for optimal growth. If you don’t have access to this type of soil, a mix of coco peat and milled compost should do just fine.
Don’t forget to break up any large dirt clumps before adding them to your new pot.
It’s important to mulch around your outdoor asparagus fern with aged compost, shredded bark, leaves, and grass clippings, as this will retain moisture in the soil and reduce weeds from emerging.
This will also provide additional nutrients for your plant to grow healthy and strong. Make sure you don’t cover up too much of the stem of your plant with mulch, though.
Indoors, you normally don’t need to mulch your asparagus fern. However, if the indoor humidity is too low, a good layer of compost mulch (1/2 inch or 1.25 cm) will improve moisture retention in the soil and gradually release nutrients to your plant’s roots as they become established.
Plant It in the New Pot
Gently remove the plant from its old pot and inspect its roots. If they seem overly dry, soak them in lukewarm water before planting them in their new home.
Place some soil at the bottom of your new pot, followed by your dampened plant and potting soil until everything is completely covered. Give it a few light taps on the sides so that everything settles down nicely before watering well and placing it in indirect sunlight.
10. Propagate Your Plant
Propagation is important for maintaining a healthy and bushy asparagus fern. These plants are highly prolific, so it’s relatively easy to propagate them and create more beautiful greenery.
Propagating From Division
You can easily propagate it by division if you already have an established asparagus fern plant.
- Remove the entire plant from its container and gently remove any excess dirt around the roots.
- Use a sharp knife to split the root ball in half, or more if desired. Each piece should have at least one healthy shoot with several roots attached for successful propagation.
- Replant each section into its own container and water them well.
- Place them in bright indirect light and keep them moist until new shoots emerge from the soil.
Propagating From Cuttings
Asparagus ferns can also be propagated through cuttings.
Simply take a cutting with several healthy leaves attached and dip it into rooting hormone powder before planting it in moistened perlite/organic matter mix in a small container with drainage holes at the bottom.
Keep this container in a place with bright indirect light, and ensure the soil is always moist until new shoots start growing. Once they emerge, you can gradually move the pot to an area with a brighter light for increased growth.
11. Keep Pests Away
Pests will keep your asparagus fern from becoming healthy and bushy, so here are some simple ways to keep pests away from them:
Clean Up Regularly
One of the best ways to keep pests away from your asparagus fern is by doing regular clean-up by removing dead or dying leaves and trimming overgrown branches. This will prevent pests, such as mites, aphids, and mealybugs, from taking hold in the first place.
It will also reduce the chances of fungal diseases spreading throughout your plant.
Keep an Eye Out for Pests
It’s always a good idea to inspect your asparagus fern regularly for signs of pest activity or disease. Be sure to look for webbing on the stems or leaves, which could indicate mite activity.
Yellow spots on the leaves or stunted growth could indicate aphids. On the other hand, white residue on the leaves might be mealybugs or other insects like scale bugs. If you notice any of these signs early on, it’ll be much easier to treat them before they go out of control.
Use Natural Remedies
If you find that your asparagus fern has been infested with pests, there are several natural remedies that can help get rid of them without harming your plant in the process. For instance, spraying water mixed with dish soap is a great way to naturally remove mealybugs and aphids.
You can also use neem oil or horticultural oil spray, which are effective at killing mites without causing any damage to the plant itself. Additionally, adding beneficial insects such as ladybugs into your garden is another great way to keep pests at bay naturally.
Asparagus ferns sometimes grow elongated and leggy instead of dense and bushy because of several environmental factors. To make it bushier, you can prune back the bare stems and pinch off the top of each stem to promote new growth.
You must also ensure the plant gets enough indirect sunlight to sustain itself.
Generous watering and fertilization in the summer months are beneficial to growth. The same goes for humid environments and higher temperatures.