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Keep the plant in a well-lit location (like near a window) away from direct sunlight too much heat and light can stunt growth and burn the leaves. It should also be away from drafts, heat vents, fireplaces or other sources of hot air. Move an indoors plant outdoors in summer to a shady location. It is best to keep in a normal house temperature range, about 65 to 75F (18 to 20C). That being said, cooler night temperatures can be used to initiate blooming. We'll discuss getting it to bloom in the final section. If it's in a north or east-facing window, you won't have to worry about light. But if it's in a south or west-facing window, diffuse the light with semi-transparent curtains or some other light-diffusing device. Put a tray of water next to the plant so that the water evaporates and provides humidity. Alternatively, you can make a humidity tray by placing the pot on a waterproof saucer that is filled with gravel and halfway filled with water. Make sure to not let the pot touch the water when it is sitting on the gravel; otherwise the pot will wick up water and make it easier for the roots to rot. 50 to 60% humidity is the ultimate goal. If your environment is close to that, you should be fine. For the container, some of the cheap nursery planters will work well, and orchid planters (the plastic basket kind) work well also. Pair this planter with a planter that will hold water and allow the basket to fit down into it. Then, place a few medium sized rocks into the bottom so that the basket container will be held about an inch above the bottom. Use a combination of 3 parts potting soil to one part sand for the potting medium. An alternative is one part potting soil, two parts peat moss or compost, and one part sharp sand or perlite. Whichever way you go, pour about two inches of room temperature water into the outer container and set the basket container inside. After about twelve hours, pour out any remaining water. Repeat this as often as the plant needs water; it will vary based on your home's condition. Monitor its need with a moisture prod and adjust accordingly. Plants that are actively growing should be given a blooming houseplant-type fertilizer. This is best done for a plant that is 2-3 weeks old. Follow the label directions for how much and how often to feed. Fertilizing is important to keep the plant in good condition; the joints are fragile and can break apart if the plant descends into poor health. Generally, it should be fertilized 2-4 times a year with a 20-20-20 feed, but stop feeding about a month before the buds appear (this usually means stopping by the end of October).

Summary:
Give your Christmas Cactus bright but indirect light. Provide the plant a source of humidity if you live in a dry environment. Use a well-draining container and well-draining soil. Add fertilizer to assist plant growth.