The poinsettia is a plant that lifts the Christmas spirit with its bright red appearance. Many of you may have bought one during the winter and are taking good care of it.
However, come the next Christmas season, many might be troubled by the thought, “Why isn’t my poinsettia turning red?”
In this guide, I will thoroughly explain the reasons why poinsettias don’t turn red and the methods to make them red.
If you’re worried that making a poinsettia red is something only a professional can do, fear not. While it does take some effort, even beginners can turn a poinsettia red with a little preparation in advance.
Why Doesn’t a Poinsettia Turn Red?
You’re probably aware that the green pigment chlorophyll gives leaves their vibrant color, but did you know that another pigment, called anthocyanin, is responsible for the bright red hue we see in plants like poinsettias?
To achieve that stunning red, you’ll need to take specific steps to induce this pigment. Let’s dive into the reasons why poinsettias might not turn red and explore how you can make them shine in your garden or pot.
1- The Poinsettia Doesn’t Turn Red Because the Bracts Aren’t Present
As you may know, the red part of the poinsettia is its flower.
However, not all the red parts are flowers. The buds in the center are flower buds, and the red parts surrounding them are called “bracts”.
Bracts are a type of leaf that protects the flower buds. Therefore, if the flower buds are not present, the poinsettia’s characteristic red bracts will not appear.
In the case of a poinsettia not turning red, the plant likely does not have flower buds attached.
2- Poinsettias and Short-Day Plants
Poinsettias are considered “short-day plants” because they bloom when they receive less sunlight.
You might think, “If I take good care of it, it will eventually bud.” However, poinsettias rarely bud if you just let them grow as they are.
Why? Because Poinsettias are “short-day plants.”
Note: Poinsettias might bud around January or February when the days are shorter.
Short-day plants are those that bud when they receive less sunlight. These plants sense the shorter sunlight and produce a special substance that triggers budding.
In other words, poinsettias won’t easily bloom if you just let them grow; they won’t turn red.
Professionals make poinsettias red for the Christmas season in December through careful management (making them bloom).
Making Poinsettias Bloom: Lengthening Nights, Shortening Days
To make poinsettias bloom, you must make nights longer and days shorter. This process is known as “short-day treatment.”
To make poinsettias red (bloom) around December, you need to perform a short-day treatment. Of course, you can do this at home.
However, without short-day treatment, poinsettias may still bud in January or February when the days are shorter.
But if you want to color poinsettias red for the Christmas season in December, short-day treatment is necessary.
In the following section, I will introduce simple ways to make poinsettias red, even for beginners.
Note: Turning poinsettias red takes effort and patience, but the process itself is quite simple.
How to Turn Poinsettias Red?
Let’s look at how to make your poinsettias red. As previously mentioned, you need to “lengthen the nights and shorten the days.”
This is known as “short-day treatment.” Start the treatment one to two months before you want to make your poinsettias red.
Step 1: Lengthen Nights, Shorten Days (Every day from mid-September)
If you want to turn poinsettias red around December, start reducing their exposure to light from mid-September. Work on it daily for about a month to a month and a half.
Focus is key. Even one day of forgetting to shield from the light, or not completely blocking it, can lead to failure.
Prepare something to completely block the light, like:
- Cardboard (cover the plant entirely, sealing any gaps with tape)
- A few black plastic bags (put the pot in and clip it shut)
Note: As poinsettias react to even slight light (fluorescent light or street lights), ensure complete darkness beforehand.
Step 2: Block Light Completely from 5 PM to 7 AM (Evening)
From mid-September to early October, adjust so that the poinsettias get less light. From around 5 PM to 7 AM, use cardboard or black plastic bags to completely shield them.
You might think, “I’ll just move it indoors,” but poinsettias react to fluorescent lights, so you must completely block the light.
- Using cardboard: Seal any gaps with tape, and cover with a black cloth to prevent any light.
- Using black plastic bags: Use several layers to block the light completely.
Note: For about two months, you’ll need to do this daily at 5 PM and 7 AM. Set a timer on your smartphone to remind you!
Step 3: Care in a Warm Place
Even during the short-day treatment, expose your poinsettias to as much sunlight as possible during the day. Keep them in a well-ventilated, semi-shaded spot.
However, be mindful of the “cold.” Poinsettias prefer warmth. Make sure they stay above 50°F (10°C).
If exposed to cold, the leaves will gradually turn yellow and fall. Be mindful of the roots getting cold through watering, too.
During the cold season, the golden rule for watering poinsettias is to “keep the roots as warm as possible.”
Water Generously When Soil is Dry: Water generously when the soil is dry but avoid watering during chilly mornings and evenings, as it can cause the roots to cool and weaken the plant.
Water During Warm Daytime: Provide water during the warm daytime, preferably lukewarm or room temperature water (around 30 degrees Celsius [86 degrees Fahrenheit]).
Dispose of Water in the Tray Regularly: Regularly discard any water that accumulates in the tray and be mindful not to create a damp environment.
Tip: After watering, place the potted plant on folded newspaper or layered cloths to absorb excess moisture, which also helps keep the roots warm.
Poinsettias Dislike Cold and Damp Conditions: Poinsettias are averse to cold and dampness.
Method Step 4: Manage in a Warm and Bright Place After Short-Day Treatment
Short-day treatment alone won’t immediately turn the poinsettias red.
They won’t begin to turn red right after short-day treatment but rather start budding and gaining a reddish hue about a month later.
Are Poinsettias Strong Against the Cold Because They’re a Christmas Flower? Many people may think that “poinsettias are strong against the cold” because they are known as Christmas flowers.
However, the opposite is true. Poinsettias love heat. Native to Mexico, they are not resistant to cold and need at least 10 degrees Celsius (50 degrees Fahrenheit).
Key Takeaways
I’ve shared the reasons why poinsettias don’t turn red and the methods to make them red. Making poinsettias red is simple, but it does take effort and time.
However, when you see the poinsettia you’ve worked on turning red for the Christmas season, there’s no doubt you’ll feel great accomplishment and joy. I hope you’ll give it a try, using this article as your guide!
Poinsettias don’t turn red Because there are no flower buds (bracts are not present) ⇒ A little effort is needed to induce the formation of flower buds to make poinsettias red.
How to Make Poinsettias Red [Steps]
- Adjust Light Exposure: Starting from mid-September, reduce the amount of light exposure (about 2 months, every day)
- Block Light Completely: From around 5 pm to 7 am, ensure no light gets to the plant
- Keep in a Warm Place: Manage it in a warm place, and provide moderate sunlight during the day
- Continue Care After Short Day Treatment: Even after completing the short-day treatment, keep it in a warm spot that receives as much sunlight as possible