The Secret To A Thriving Christmas Cactus Might Be Hiding In Your Bathroom

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It can be a little bit tricky to care for a Christmas cactus (Schlumbergera x buckleyi) — these plants must spend at least 14 hours a day in complete darkness, and they need to grow in an environment that's about 68 degrees Fahrenheit. Like its similar-looking cousin, the Thanksgiving cactus, a Christmas cactus also needs more magnesium than many other houseplants. You can help yours thrive by giving it a taste of a magnesium-rich product from your bathroom's medicine cabinet: Epsom salt. Your Christmas cactus is likely to benefit from just a few doses of this bath soak during its growing season, and it'll be more than worth the effort when the plant welcomes the yuletide season with a profusion of red or pink flowers.

Tending to your plant's nutritional needs is almost as crucial as maintaining the correct temperature and light levels. From early spring through the end of summer, a Christmas cactus requires a monthly application of a balanced fertilizer. Generally speaking, the best fertilizers for cactuses are relatively low in nitrogen but abundant in root-supporting phosphorus. A Christmas cactus should also receive a magnesium infusion each month, but this should be given during weeks that you don't feed the plant its regular fertilizer.

Sprinkling a handful of Epsom salt onto your potted Christmas cactus isn't the best way to meet its magnesium needs, however. Instead, these crystals of magnesium sulfate should be dissolved in water first. You'll need about a gallon of water for every teaspoon of Epsom salt that you use. Be careful not to overwater your Christmas cactus when delivering its magnesium boost, as this can cause root rot. Even a little standing water in the plant's drip tray can lead to problems. 

Though applying your diluted Epsom salt with a watering can is just fine, try spraying it on the foliage of your Christmas cactus if it's showing signs of magnesium deficiency. This ailment often causes yellowing between the veins of leaves as well as lackluster growth. Applying the Epsom salt directly to the leaves of your Christmas cactus helps the plant absorb its nutrients faster. If you take the spray route, be sure to spritz the bottoms of the leaves, starting at the bottom of the plant and then moving upward and outward.

Have some diluted Epsom salt left over after fertilizing your Christmas cactus? Share it with some of your magnesium-loving vegetable plants, such as tomatoes. You can also use Epsom salt on many other houseplants, from peace lilies to miniature roses. For best results, perform a soil test to determine exactly how much feeding your plants need. Some soil nutrient tests only measure nitrogen, phosphorus, and potassium levels, so be sure to get one that measures magnesium levels as well — for example, the MySoil Test Kit.