Poinsettias are a holiday staple, with their vibrant red and green foliage brightening up homes and public spaces during the winter months But these tropical plants are sensitive to cold temperatures, which can quickly damage or kill them if proper care isn’t taken In this guide, we’ll look at how cold is too cold for poinsettias and provide tips on protecting them when the thermometer dips.
Understanding Poinsettia Temperature Needs
Poinsettias are native to southern Mexico and Guatemala where temperatures remain warm and frost-free. They thrive in temperatures between 65-75°F during the day and 60-65°F at night. Anything below 50°F can cause poinsettias to drop leaves and suffer damage. Prolonged exposure to temperatures in the 40s or below can be fatal.
Sudden drops in temperature, even if still above freezing, can shock poinsettias Their tropical ancestry means they don’t tolerate cold drafts well. Keeping them in a stable environment is key to their health
Signs of Cold Stress in Poinsettias
It’s easy to spot when a poinsettia is getting too chilly. Initial signs include:
- Wilting or drooping leaves
- Curling or crinkling of leaves
- Faded coloration, turning from vibrant reds/pinks to paler washed-out hues
- Leaf drop as the plant jettisons leaves to conserve energy
These are clear indicators that action needs to be taken to warm up the plant. Left unchecked, the cold stress can worsen and may kill the plant entirely.
Ideal Growing Zones for Poinsettias
In the wild, poinsettias grow in USDA Hardiness Zones 10-12. When kept as houseplants, they can thrive anywhere provided they are protected from cold and frost.
If planting poinsettias outside, they will survive best in Zone 9 and warmer. Zone 9 covers parts of the southeast, Gulf Coast, Arizona, and California. Even in these warm zones, extra winter protection like mulch may be needed.
Before placing a poinsettia plant outside, double check your zone to ensure it will tolerate your winter temperatures. A sudden cold snap can damage an unprotected plant.
Tips for Protecting Poinsettias from the Cold
Here are some tips to keep your poinsettia cozy when temperatures get chilly:
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Site poinsettias away from cold drafts near windows, doors, and air vents. Choose a stable, well-insulated spot.
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Avoid placing poinsettias next to cold surfaces like windowsills. Use a plant stand to elevate and insulate the pot.
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Don’t situate poinsettias directly next to heat sources which can dry them out. Aim for 65-70°F temperatures.
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When transporting poinsettias on cold days, cover them and keep them in a warm vehicle. Don’t leave them in a cold car!
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Outdoor poinsettias should be heavily mulched and protected from frost and freezing. Bring potted plants indoors in winter.
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Monitor both indoor and outdoor plants for signs of cold stress like wilting. Take prompt action to get them warmer.
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Water poinsettias properly to avoid temperature fluctuations from overly wet/dry soil. Feel soil before watering.
Caring for Poinsettias Year-Round
With the right care, poinsettias can live for many years as houseplants after the holidays. Be sure to:
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Repot in spring using well-draining soil. Choose a pot just one size larger.
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Prune back stems in spring to encourage bushy new growth.
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Place in bright, filtered light indoors. Avoid direct hot sun which can burn leaves.
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Water when the top inch of soil is dry. Take care not to overwater.
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Fertilize monthly during the active growing season with a balanced houseplant food.
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Gradually introduce outdoor plants to increasing sunlight in spring.
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Bring poinsettias back indoors well before nighttime temperatures drop below 50°F.
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Protect from cold drafts and drastic temperature fluctuations indoors and out.
Keeping Poinsettias Cozy in Chilly Weather
Poinsettias require tropical warmth to put on their iconic holiday show of bright red and green leaves. Taking steps to protect them from cold drafts and temperatures below 50°F will help ensure they stay healthy and colorful.
With proper care, these festive plants can thrive as long-lasting houseplants beyond the holiday season. Just be vigilant about shielding them from anything too cold for their delicate tropical nature. A few simple precautions will keep your poinsettia going strong.
Keeping Your Plant Comfortable
Even in Zones 9 to 11, temperatures still sometimes fall below poinsettia’s lower comfort limit of 50°F.
To compensate for this, you may need to find a microclimate in your landscape, a spot that is warmer than others, such as in front of a south facing wall, to improve your Christmas star’s chances of surviving out in the elements.
Mulching over the plant’s roots during the cold months will also help ensure that it stays alive, even if the stems get bitten by a cold snap.
If your outdoor poinsettias are in pots or planters rather than in the ground, keep an eye on the weather during cold spells and be prepared to bring them indoors if temperatures are forecast to fall below 50°F.
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Yes, poinsettia, Euphorbia pulcherrima, can be put outside during the warm months. But it is a tender tropical plant, so wait until the temperature is consistently above 50°F at night before placing it outside.
You will need to acclimate it by taking it out gradually, not all at once. When the days start to warm up into the 50s and 60s you can put it out during the day and take it inside at night. Gradually you can leave it outside for longer periods of time. After a couple of weeks you can leave it out all night, provided the nights dont get too cold.
Continue to fertilize it and be sure to pinch back the growing tips to induce bushiness. Bring it back indoors before frost and subject it to 14 hours of total darkness each night until the bracts begin to show color. Then it can be brought into the light and treated as a houseplant. The darkness must be uninterrupted each night or the buds will fail to form. To ensure success, keep the night temperatures low and dont forget to expose the plant to light each day after the 14 hours of darkness.
You can find instructions on encouraging re-flowering, which includes a period of dormancy, in our Guide to Poinsettia.
– Courtesy of NYBG Plant Information Service
How cold is too cold for poinsettias?
FAQ
What is the lowest temperature poinsettias can tolerate?
Temperature: Indoor temperatures of 65 to 70 degrees F are ideal. Avoid placing poinsettias where the temperature fluctuates or may be drying, such as near cold drafts, heat ducts, fireplaces, fans, space heaters, etc. Poinsettias will suffer damage if they are exposed to temperatures below 50 degrees F.
At what temperature should poinsettias be brought inside?
Place them in a light-filled room away from drafts. They do best in rooms between 55 and 65 F at night and 65 to 70 F during the day.
Can potted poinsettias be outside in the cold?
Poinsettia plants should not be exposed to cold temperatures. Poinsettia is best placed in a paper plant sleeve to protect the plant from the cold as well as to prevent it from breaking. If temperatures are well below freezing, all parts of the plant should be protected from the cold.
How sensitive are poinsettias to the cold?
Poinsettias are sensitive to cold temperatures. Even temperatures in the low 40s can cause leaves or petals to drop. If it is a long distance from store to the car, cover the plant with a bag or sweater. More poinsettia plants are damaged by overwatering than underwatering.