How to make a poinsettia turn red - the trick is putting it in the dark, but you must get the timing right

Adorably nicknamed ‘the Christmas flower,’ the poinsettia and its red flowers have long been associated with the festive period. But what do you do if your poinsettia leaves have turned green? And how do you make poinsettia turn red again?

Poinsettias are fairly low maintenance. Even if you do everything you can to follow the poinsettia care tips to a tee, though, it’s still possible to run into complications with this plant. You might ask yourself why your poinsettia is dropping leaves, or you might wonder why they’re a completely different colour from what you thought. 

To help you make your poinsettia turn red in time for Christmas, we’ve consulted with plant experts to give you all of the tips and tricks you need to make your plant merry and bright again. 

How to make a poinsettia turn red

‘To make your poinsettia turn red and thrive, give it some 'me time' in the dark’, says Alex Biggart, florist at 123 Flowers. But what does that ‘me time’ involve? Well, there’s no use giving your poinsettia a face mask and your Netflix password. This is a simple step-by-step guide on how to make your poinsettia turn red again.

What you’ll need

• Poinsettia plant 
• Cardboard box or plastic bag
• Watering can - like this Stainless Steel Watering Can from John Lewis
• Plant food - like this Baby Bio Houseplant Food from Amazon

Step-by-step

1. Choose the right time

If you want to ensure that your poinsettia is looking its best on Christmas day, the ideal time to start this process is in October. And while it is possible to make your poinsettia turn red again if you start later than October, it may be that the colour won’t be as vibrant as you’d hope. 

2. Put your poinsettia in the dark

Steve Chilton, garden expert at LeisureBench, explains the next step. ‘Around early October time, poinsettia requires uninterrupted darkness for at least 14 hours a day. To do this, cover the plant with a light-proof material, such as a cardboard box or black plastic bag, every evening until the following morning.’ 

However, if you have an airing cupboard or dark room with blackout curtains, this could also work. The aim is to keep your poinsettia away from any kind of natural or artificial light, as you essentially want to reverse the process of photosynthesis to turn your poinsettia red again.

Alex says, ‘Poinsettia 'flowers' are actually modified leaves called bracts. Reducing exposure to sunlight stops the plants from producing chlorophyll, which gives them a green pigment. This, in turn, changes the bracts to the signature red colour.’

Steve Chilton

Steve is a passionate and knowledgeable garden expert with several years of experience within the field and has developed strong expertise for all things nature and plants. Steve is a keen educator and loves to share this knowledge with others. He strives to simplify complex garden practices and encourage eco-friendly gardening.

3. Bring it out during the day

After putting your poinsettia to bed for the evening, it’s important to bring it out during the day. Place it on a windowsill or in a sunny area of your house so it receives sufficient sunlight, and aim to keep the temperature between 15 to 24C. 

4. Repeat the routine

You can then repeat this routine for the next few weeks, making sure you also maintain a regular watering and fertilising schedule to keep it as healthy as possible. 

‘Let the top inch of soil dry out between drinks and feed it some plant food every few weeks,’ Alex says. But make sure you don’t overwater it, as overwatering is one of the easiest ways to kill your poinsettia. 

The experts suggest continuing this routine until mid-November. 

5. Stop the darkness treatment

When mid-November comes around, Steve suggests stopping the darkness treatments, as the plant ‘should begin to show signs of producing red bracts within a few weeks.’ 

This step requires some patience, and it’s important to understand that turning your poinsettia red isn’t a quick fix. It’ll take a few weeks to see the results of the darkness treatment. So, all you can do is wait patiently and maintain a regular watering and fertilising schedule. 

6. Cut back any faded leaves

While this process is almost always successful in making your poinsettia turn red, that doesn’t mean that it’ll look like a perfect specimen when you’re finished. In fact, you may find that some of its leaves look a little worse for wear. Thankfully, you can give your poinsettia a little prune. 

‘Once the red colour appears again, you can get rid of any faded or yellowed leaves to enhance the plant's overall appearance,’ explains Steve. 

And while you may be worried that you’ve missed the boat on turning your poinsettia red, you’ve still got time. Steve finishes by stating, ‘You can do this later on in the year, but it's important to follow the same timeframe.’

FAQs

No need to throw your poinsettia away if the leaves are green. Just give it some ‘me time’ instead!