Remember that poinsettias are tropical plants that require maximum light, warmth and humidity to survive. While blooming, your plant will do best under these conditions:
- Light: Poinsettias need at least six hours of bright, indirect sunlight a day. Choose the brightest window you can, but don’t allow the plant to touch cold glass.
- Temperature: The ideal temperature for poinsettias is between 65° and 75° F. They are susceptible to leaf drop and will become scraggly looking if exposed to cold drafts or extreme temperature changes.
- Watering: Thoroughly water the plant when the soil feels dry, then empty the drainage tray so your poinsettia doesn’t sit in water. Mist regularly, or add a pebble tray or humidifier to increase humidity.
- Nutrients: Don’t feed your poinsettia while it’s blooming. Food comes later — see below for instructions.
Poinsettia Care Calendar
The challenge of growing poinsettias lies in getting them to bloom again. Follow this care schedule to encourage years of growth and flowering.
- Winter: (January to March) Continue watering and enjoying your poinsettia in a sunny window for as long as it’s blooming.
- Spring: (March to May) After the blooms fade, the plant enters a resting season until summer. Prune your plant back to 6 to 8 inches tall. Reduce watering and allow the plant to get completely dry between waterings.
- Summer: (May to September) Repot, if needed, in light potting mix, moving to a slightly larger pot if it appears root-bound. When you see new growth, begin feeding every two weeks with a balanced organic fertilizer.
Pinch back the stems as they grow, to encourage branching. You can put your poinsettia outdoors for the summer, but bring it back inside before temperatures drop into the 50s F.
- Fall: (October) Poinsettias bloom in response to shorter days. For about 8 to 10 weeks prior to the desired bloom time, put your poinsettia in complete darkness for 12 to 15 hours per day.
You can cover it with a thick cardboard box or black plastic bag, or move the plant to a closet, but it needs TOTAL darkness for at least 12 hours per day — even indoor lighting will disrupt the process.
During the day, remove the covering and make sure the plant gets at least 6 hours of sunlight. Water and feed as usual.
- Holiday Blooms: (November to December) After 8 to 10 weeks of darkness treatment, you should see flower buds on your poinsettia.
Once you do, you can discontinue the darkness treatment and bring it back out to your window after Thanksgiving to enjoy.
Continue watering, but stop feeding until spring.
- Poinsettia (Royal Horticultural Society)