Last month, I wrote about post-holiday care for amaryllis and paperwhites. But I know Christmas cactus and poinsettias also are taking up residence in many of your homes. Here’s how to care for them.
I’ve heard a story or two of folks keeping these plants under fluorescent lights in the office year-round, watering regularly and being rewarded with annual blooms. I do not know any of these people personally.
If you want to guarantee a holiday show, follow this admittedly annoying protocol. If you love Christmas cactus, it will be worth it.
Repot the plant into the next-size container in March using one-third each of ordinary houseplant potting mix, coarse sand and perlite (repeat every two years). Place the pot by a window where it will receive indirect sunlight, and water regularly, incorporating African violet fertilizer diluted to half strength every second watering.
In early July, move the plant outdoors to a bright, sunny spot, letting it rely on rain except during dry spells. Bring the plant indoors in September and keep it in a cool spot (50 to 60 degrees), misting twice a week and watering sparingly.
To form buds, these plants require a period of complete darkness from 5 p.m. to 8 a.m. daily for eight to 10 weeks before the desired bloom time, typically the end of December. Simple math places the beginning of this window at mid- to late-October. You must remember to move it out of the closet or other blacked-out location daily, and keep it in the main part of the house from 8 a.m. to 5 p.m. (Yes, you’ll need to rush home each day as if you had a dog to walk.)
The madness will end when you spy buds forming. Move the plant to a sunny spot in the house and resume watering regularly.
Do. Not. Move. Or. Even. Touch. The. Pot. Buds will drop at the slightest provocation. Really.
To ensure a holiday show, continue watering poinsettias until they stop "blooming." (Of course, a poinsettia’s “flowers” aren’t flowers at all, but modified leaves called bracts. For simplicity's sake, we refer to them as flowers that “bloom" — until the bracts fall off and you’re left with green leaves.)
Allow plants to dry out, and when they go dormant, move pots to a cool, dark spot, such as an unheated cellar, and place pots on their sides. Leave them there until April, checking periodically and misting if stems begin to shrivel. Move back into the main part of the house in April; trim each stem by 2 inches and set by a sunny window. Keep the soil consistently moist but not soggy.
Around Memorial Day, if you wish, you can move them outdoors until September. Otherwise, continue to care for them indoors, keeping in mind that they thrive best when daytime temperatures are between 70 and 75 degrees (and 60 to 65 at night). Regardless, fertilize once a month with one teaspoon of a 20-20-20 fertilizer dissolved in a gallon of water.
To form buds, poinsettias should be deprived of light for 15 hours daily for 40 days. For holiday blooms, this should begin on Oct. 1. During this period, keep plants in a bright, sunny spot from 8 a.m. to 5 p.m. daily, and move into a dark closet from 5 p.m. to 8 a.m. If you skip this for even one night, buds may not form.
Bracts should begin turning red in early to mid-November. That's your cue to move them back into the main part of the house (and tell your boss you're free to work overtime again).