Why are my peace lily leaves turning yellow? Plant experts reveal all

Why are my peace lily leaves turning yellow? It is a question that many plant owners have probably asked before now as the beloved low-maintenance plant is renowned for throwing the odd tantrum by way of yellow leaves. 

As one of the best fragrant plants to make your house smell good, lilies in all forms are a perfect choice when it comes to what greenery to have in your home. Unfortunately, peace lilies, which strangely don't belong to the Lilium family, can often produce yellowing leaves. 

"Peace lilies make beautiful houseplants, but yellow leaves often result in owners throwing them out," says Mark Lane, a gardening expert and BBC's Gardeners World presenter. However, he says this need not be the case because there are ways to resurrect your plant before calling it quits.

Why are my peace lily leaves turning yellow? 

Unfortunately, there are a few reasons that your previously thriving peace lily is showing signs of struggle and yellowing. It's not just a matter of knowing how to clean plant leaves properly, but actually, the number of times you're watering your plant can be the culprit for leaf damage.

Mark Lane

Not only is Mark a presenter on BBC's Gardeners World he is also an accredited gardening expert at stairlift and homelift company Stannah. Mark also runs his own gardening business when not providing useful tips and tricks for blossoming green thumbs. 

1. Overwatering and underwatering

More often than not you're plants are reacting to a water shortage or waterlogging, similar to why bay tree leaves turn brown, looking at how often you're watering the plant is a great first step. 

"These noticeable changes in the plant are frequently down to underwatering or overwatering," explains Mark. If you suspect that perhaps your watering hasn't been up to par then there is a quick way to check that this is the issue. Mark suggests lifting the plant and soil out of the pot, if the top half of the soil is completely dry then you need to water your peace lily, making sure all excess water can drain away.

It's important to ensure your plant has sufficient drainage, even more so for the peace lily as they are one of the plants that help with condensation in your home.  Should your plant be sitting in water then this can also cause the leaves to yellow.  Using a planter that comes with a saucer can help with drainage, or you can add pebbles or broken pieces of pot underneath your plant. 

2. Water quality

Another issue can be the quality of the water you're using to water your peace lily, Mark says, "Also, tap water may contain fluoride, which peace lilies are sensitive to. Filtered water or collected rainwater is best when it comes to watering your plants." 

You can easily collect fluoride-free rainwater by investing in a water butt or simply leaving a bucket outside to collect the rain when it's forecasted. Should you be tempted to take the plunge and invest in a water butt to help with your plant watering then we found a small 100L model that comes with a handy rain diverter kit on Amazon for £59.99.

3. Sunlight

It's not just water that can massively affect your peace lily's leaf health, where you position your plant in your home can also lead to yellowing leaves. Talking to Fiona Jenkins, a Gardening Expert at My Job Quote, she says, "Peace lilies prefer bright light, but this should be indirect. Too much direct sunlight can cause the leaves to burn and turn yellow."

Of course, too much sun can also be a problem too. Fiona says, "However, it does need sufficient sunlight for photosynthesis, or this can also lead to yellowing of its leaves." So it's best to try to find a bright spot in your home with diffused sunlight, so in front of a window with a sheer curtain would be perfect. 

Fiona Jenkins

With over 25 years of experience under her belt, Fiona is a trained gardener who offers advice and insight to several trade companies and homeowners. She has also been featured as a gardening expert for several publications. 

How do you fix your yellow leaves on a peace lily?

Unfortunately, the moment your peace lily's leaves have turned yellow, whether that be from over-watering, too much sunlight or water quality there is no way to fix the affected leaves. Mark says, "Simply remove the leaf and stem as low to the base of the plant as possible." 

Should your problem keep persisting then it's recommended that you also check the roots of the plant for water damage or rot. Mark explains that if the majority of the leaves turn yellow, especially if the yellow leaf and stem in particular are soft and squishy, then this is a sign the plant has been overwatered. 

Again, there is no way to return the yellow leaves to their previous green colour, but by improving drainage of your plant any new leaves that grow will be green and healthy. If you're struggling with drainage then Mark recommends adding some horticultural grit to the soil. 

Can a yellow leaf turn green again?

Sadly it's a definite no. There's no way to resurrect your peace lily's yellowed or yellowing leaves once they've turned. Fiona explains, "When a leaf turns yellow this process is called chlorosis, and can be caused by disease, pests, nutrient deficiencies, or plant care issues. The chlorophyll in plants absorbs light, typically sunlight, and turns it into chemical energy to feed the plant." 

"Once this process of photosynthesis is affected and the plant loses its green colour there is no way for it to produce energy," she continues. As Mark instructs above, you can remove the leaf yourself or the plant will over time discard any yellowed leaves itself.  

Knowing how to treat plants that are failing or are showing signs of rot is a great way of ensuring they thrive and stick around for a lot longer. Whilst peace lilies aren't a demanding plant and unlike how to care for orchids they can be given minimal attention, it's important to look out for signs of struggle and act fast.