If you're faithfully watering a poinsettia plant from last year, it's almost time for the payoff. Work on it now and it'll bloom again for Christmas.
It's a photoperiod-sensitive plant, along with the chrysanthemum, kalanchoe and Christmas cactus, which means it begins to set buds and produce flowers as nights become longer. The key is to keep the plant in continuous and total darkness for 14 hours a day until mid-December.
Put the plant into a dark closet at 6 every evening and leave it there until 8 the next morning. Or, put a cardboard box over the plant for 14 hours. Unless it has darkness for the 14-hour period, it will not set a bud or produce a flower.
If you turn the light on, even for only a few seconds in the room where it is, it will delay blooming. The night temperature during the dark period should be from 60 to 65 degrees. In high temperatures, the setting of buds may be delayed or halted.
During the other 10 hours of the day, give the plant as much light as possible. Dim light during the 10-hours shortens its life.
Some plants may need watering every day. Water thoroughly when the soil feels dry to the touch. Use tepid water and pour it on until it comes out the drainage hole. Wait 15 minutes for excess water to drain and empty the saucer.
If the plant was outdoors for the summer, check it carefully for insects. Take a good look, too, at those that remained in the house. Use a magnifying glass so you can see pests on the leaves.
If plants are badly infested, spray them outdoors. But first try sponging the leaves with warm, soapy water twice a week. Or put the plant in the bathtub and give it a shower while rubbing the leaves with your fingers.
Cotton pads soaked in rubbing alcohol will destroy mealy bugs. Treat weekly for two or three months to get rid of bugs hatching from eggs.