How to grow and care for your Christmas cactus
Christmas Cactus are in the genus Schlumbergera and can bloom in shades of red, pink, peach and white. They seem to thrive on a certain amount of neglect which makes them good for beginners. They are very long lived and can grow to be over 100 years old. I've seen huge woody plants that have been passed down through the generations.
With the following tips, you too can grow your own indoor Christmas Cactus.
If you are good about not over-watering, regular potting soil is just fine for these plants, otherwise you may go with a mixture of one part potting soil, one part peat moss and one part sand.
Christmas Cactus like to be on the cool side especially when it's time for them to form buds. Keep temperatures between 55 degrees and 65 degrees at night and below 70 during the day for best results. Keep away from heat vents and cold drafts. Do not expose your plants to frost as they can not survive these types of temperatures.
Christmas Cactus prefer bright filtered light for the majority of the year. Intense light during spring and summer months will likely burn the leaves, so I usually move mine to a window that has a sheer curtain in front of it. Then in October I move it to a south facing window with no curtain. Refrain from using fluorescent lights for long periods of time as Christmas Cactus require 14 hours of darkness to form buds.
Christmas Cactus like to be on the dry side, especially when they are not blooming. You may not need to water your plant but twice a month during late winter through early autumn. It will depend on the type of soil and humidity, but in general, they don't need a lot of water unless they are setting buds. Check the top inch or two of the potting soil and if it feels dry, water the pot until water runs out the bottom and then remove any water that remains in the saucer. Leaving a plant sitting in water will eventually rot the roots and kill the plant. Despite their common name of cactus, Christmas Cactus cannot go without water for long periods of time, so if you notice that the tips of the plant are starting to shrivel, water the plant. It may take a few days for the plant to perk back up, but it should.
Christmas Cactus don't need a lot of fertilizer. In fact, too much nitrogen will prevent buds from forming, so fertilize only once a month with an all-purpose water soluble fertilizer from Spring through Summer. To be honest I don't fertilize mine very often. I may put a little compost tea on them in the summer when I have leftovers from the garden and the potting soil I use has a slow release fertilizer in it, so adding more fertilizer hasn't been necessary.