Dr. Grow: For poinsettias, it's beginning to look a lot like Christmas

A bonita poinsettia plant shows lateral branching with lighter-colored leaves after being "pinched." The process provides more but smaller bracts.

I've been playing a lot of Christmas carols in my head lately. I know the weather has recently been very hot and extremely humid -- not weather that would put you in the mood for Christmas. Yet, if you're in the greenhouse or retail business, you are already thinking about and preparing for Christmas.

Greenhouses that sell poinsettias have been feverishly potting up new cuttings during the last two months. They are also busy fertilizing, pinching and watering the 50,000,000 or so plants that are sold each year.

So why I am writing about poinsettias now? If you're like most gardeners I know, you have saved your poinsettia from last year.

(For you non-gardeners I'll explain something. Most gardeners can't toss any plant that shows even a hint of life in it.)

Here are some instructions on how to make that plant "bloom" again this year. You need to get started now or you'll have to watch it come into color in January, February or March, way past the holiday season.

Make sure your old poinsettia is well watered and fertilized. If it is root bound, then repot it into a pot that is only one to two inches larger than the pot it is in. Be sure to use a good grade of soil-less potting mix to supplement the existing soil.

Decide whether you want a few large blooms or several smaller ones. If you want a few large blooms then prune out several of the branches and leave only three to five main stems. If you want several smaller blooms, then leave all of the stems. Next, shear the plant by cutting the existing stems about halfway back. This is called a pinch.

Continue to grow your pinched poinsettia where is gets a lot of light. If you grew it outside during the summer, then bring it into the house for the winter when the night time temperatures begin to fall to 50 degrees. Place the plant in front of a window. You may need to supplement the natural light with a grow light to get enough light for the plant.

Adjust your watering habits once you have brought the plant inside. It will probably demand as much water inside as it did outside.

Around the first of October, give your poinsettia short days and long nights. Do this by covering the plant with a large box, or move it into a closet or a closed room each evening. Poinsettias requires at least 13 hours of darkness every 24 hours for a period of 9 to 11 weeks. These short days and long nights trigger it to "bloom."

These "blooms" are not flowers at all, but are bracts. The actual flowers are little yellow structures in the middle of the bracts.

Be sure that no pulse of light hits the plant during the night time phase. Don't open the closet to find something. If any light hits the poinsettia, the effect of the short day and long night is nullified.

Remember during the day, return the plant to a location in your house that receives a lot of light. Continue to fertilize and water as needed.

I know this sounds like a lot of trouble, but it is very satisfying to be able to coax that almost forgotten plant into a beautiful specimen again. It's also a fun thing do with your kids or grandchildren. Oh, by the way, Merry Christmas to everyone.

Paul Schnare of Cape girardeau has been in the lawn and garden business for more than 20 years. He's an adjunct professor in horticulture at Southeast Missouri State University.