Pointers on poinsettias

In a couple of recent columns, I wrote about the culture and care of poinsettias. At that time, I promised another column to give some pointers on how to care for your plants now that the holidays are over. If you want to keep your poinsettia around for a long time, and especially if you are interested in trying to get it to bloom again, this is the article for you.

First of all, you need to heed the advice that I gave in my previous articles about where to place your poinsettia, optimal temperatures, lighting requirements, watering, and other cultural considerations. If you don’t have those articles, you can find them on my web site or call the Daviess County Extension Center and I’ll be happy to send them to you.

Your poinsettia comes to you from the greenhouse with some fertilizer in the potting media. But that will soon run out, so now it’s time to start thinking about adding fertilizer from time to time. By mid-January, you should start fertilizing them, using a fertilizer meant for house plants. This needs to be done on a monthly basis.

If you would like to keep your poinsettia around until next Christmas, and see it bloom again, there are a number of tasks that you will need to perform. Around the end of April or beginning of May, prune the plant back to around six to eight inches or so, keeping the shape that you want to see later on. Place it near a sunny window, and let it re-grow.

You may want to re-pot the plant in June, to a slightly larger pot. The soil mix should contain a high percentage of organic matter, such as peat moss.

After the night time low temperatures outside are staying well above 50 degrees F., it’s a good idea to take your poinsettias outdoors. A sunny spot makes an excellent location, with a little light afternoon shade. Be sure to turn the pot or move it around every once in a while so that roots do not grow through the hole in the bottom of the pot into the soil. When it’s time to bring them back inside, inspect your plants closely so that you don’t bring along unwanted insect pests into your home.

In August, you may want to pinch off terminal buds to encourage side branching. This will result in a shorter, bushier plant, with more blooms.

To insure that your poinsettia blooms for Christmas, you do need to follow a special procedure. Poinsettias are short-day plants, which means that they need long hours of darkness to bloom. On Oct. 1, you should start covering your poinsettias for 14 or so hours per day. One guide suggests covering the plants at 5 p.m., and uncovering them the next day at 8 a.m. The cover should exclude all light. They need total darkness. Even a small amount of light will be enough to inhibit flower formation.

This process needs to continue until the bracts have started developing their color. It won’t hurt to keep the process up until the bracts are fully expanded and showing good color.