It can be quite alarming when you start to notice that your beloved Asparagus Fern is starting to turn yellow and you aren’t sure what is causing it. If there are yellow leaves on your Asparagus Fern then it is definitely trying to tell you that something isn’t right with either its environment or the care that it is being given. Below we explain all of the causes of yellow leaves on an Asparagus Fern which should hopefully help you to diagnose the cause.
Too much light can cause yellow Asparagus Fern leaves
Lighting is always an important element to take into consideration when caring for your houseplants and Asparagus Ferns are no different. If your Fern is getting too much bright light you’ll start to notice yellowy patches throughout the leaves. This is due to the sunlight burning the leaves which is unfortunately irreversible. Asparagus Ferns have delicate leaves so are more prone to sunburn than other houseplants so we recommend moving your Asparagus Fern into a slightly shadier place, and if there’s no improvement move it a little further again until you find it’s the perfect spot. Using a light meter can help you figure out the best spot for your Asparagus Fern.
You can carefully trim away the burnt yellow and brown leaves so your Asparagus Fern can focus all of its energy on new healthy growth.
Overwatering may be causing the yellow leaves on your Asparagus Fern
If the leaves on your Asparagus Fern have turned yellow you may be overwatering your plant. Another thing to look out for that is caused by overwatering is whether those yellow leaves are starting to drop from the plant.
Overwatering is one of the main killers of Asparagus Fern as you might not always be able to tell before it is too late. Asparagus Ferns don’t like to be sitting in a lot of water for long periods of time as this can lead to root rot meaning the plant becomes unstable and also cannot get needed nutrients from its root system. Waterlogged soil gives off quite a damp and musty smell so make sure to check this every so often too as this may start to happen before your Fern develops visible yellow leaves.
To check whether the cause of the yellow leaves on your Asparagus Fern is overwatering, check the moisture of the soil immediately and adjust your watering schedule accordingly. The most reliable way to know if your Asparagus Fern needs watering is by using a moisture meter. We also recommend replacing the potting soil straight away (rather than waiting for it to naturally dry out) so that the roots can begin to recover. Always use a high-quality potting mix to make sure your Fern is getting the right balance of nutrients. Cut away the rotten roots and dead yellow leaves so that your Asparagus Fern focuses on regenerating healthy growth.
Sometimes it may not be your watering schedule that is causing your Asparagus Fern’s leaves to turn yellow, but the poor draining of the soil and pot. You can very easily increase the amount of drainage in the pot of your Asparagus Fern by mixing in a small amount of perlite. This will make it far easier for water to flow through and out of the drainage holes of your pots (you should also check to make sure your pots have drainage holes). Another easy step is to add a few small stones or pebbles to the bottom of your pots, this helps in making sure that the drainage holes are never blocked by soil or any loose debris.
Although clay or terracotta pots tend to be a bit more expensive and are breakable, their upsides are much more than just the aesthetic. The clay they are made of is permeable which means that some of the water in the soil can evaporate through the sides of the pot. This isn’t the case for the plastic pots that most use, which instead hold in all of that moisture. So sometimes it is worth investing a little more to make sure that the roots of your Asparagus Fern are not sitting in too much moisture. We love these terracotta pots from Amazon.
Underwatering can also cause yellow Asparagus Fern leaves
If your Asparagus Fern’s leaves have turned yellow, dry and crispy (starting from the tips and moving through the plant) it may be because you have not given it enough water for a while. Asparagus Ferns prefer a little and often approach to watering to ensure their soil is damp but not waterlogged. If you have consistently underwatered your Fern, this may be the reason why it has develop yellow leaves. It is important to keep an eye on the moisture levels of the soil so you know when your Asparagus Fern is ready for watering.
Make sure to check the moisture in the soil before you water your Asparagus Fern. There are two really easy ways to make sure that it definitely needs water. First check the moisture at the top of the soil, if it is still damp then wait a few days before watering again. You can also lift up your Asparagus Fern carefully to check the weight of the plant before and after watering. We recommend doing this by holding the pot rather than the plant itself to avoid any damage to the delicate leaves. You will then start to be able to gauge how heavy the soil is when it is in need of water.
If you find that your Asparagus Fern feels very dry, water it a little every other day for a week. Your first instinct might be to give it loads of water straight away but this can actually be harmful to your Fern if the soil goes from one extreme to the other. Yes, plant’s can get shocked too by a sudden change in environment. So instead you want to reintroduce frequent watering for a week or two and this should solve the problem. Trim away the yellow and dried leaves and hopefully once the problem has been rectified, any new growth should be healthy and green!
The yellow leaves may be caused by a lack of nutrients
Another cause of yellowing leaves on Asparagus Ferns is a lack of nutrients. It may happen that over time the soil becomes very nutrient deficient, or the water has flushed out all of the nutrients needed. Yellow leaves are sometimes a cause of a lack of nitrogen. There are two methods which will help increase the level of nutrients for your Asparagus Fern. Firstly, remove all of the old soil in the pot and replace with new nutrient-rich houseplant potting soil. (Remember to make sure it is also well-draining to avoid waterlogging). Alternatively, you can treat with a well balanced houseplant fertiliser at half strength. Our houseplants have always liked the liquid fertiliser from Miracle Gro which is available from Amazon here.
Cold temperatures can cause yellow Asparagus Fern leaves
Asparagus Ferns prefer slightly warmer temperatures so may struggle in cold homes. Over time, the cold air will impact your Asparagus Fern’s health and may be causing them to develop yellow leaves. Make sure your Fern is away from all air conditioning vents, drafty windows or doors as the colder air can shock your plant. You can always pick up a digital thermometer to check the temperature of the spot your Asparagus Fern is sat in to see whether it needs to be moved.
Those are all of the main reasons why your Asparagus Fern may be developing yellow leaves. The most common ones are direct light and overwatering so we recommend starting with those to see if you can best diagnose the problem. Check out our Asparagus Fern care guide for more information on general care tips, recommendations and advice to help your plant thrive.
Written by Joanna Turner