Why You Should Be Adding Eggshells To Your Christmas Cactus Soil

Given the easy plant care of the Christmas cactus (Schlumbergera bridgesii), this succulent truly can be the gift that keeps on giving. In fact, Christmas cacti can live over a century and be passed down in families. This tropical plant has long been a favorite among plant parents, with its vibrant reddish-pink blooms, typically timed with its namesake holiday. Christmas cacti aren't too picky about light conditions, although they'll reward you with more flowers if you give them enough sunlight. They also need well-drained succulent potting mix and don't mind being slightly rootbound. If you're wondering how often to water your Christmas cactus, do so only when the top inch of the soil is dry. 

If you really want to get on your Christmas cactus' good side, offer it plant food that can be found among your food scraps. Eggshells have long been added to garden and houseplant soil as an easily accessible, affordable, and effective source of calcium. A 2022 study from Scientific Reports also found that, in addition to being rich in calcium, chicken eggshells contain sulfur, sodium, and magnesium — the latter of which is a mineral that Christmas cacti actually need more of than most plants. 

Just as humans need calcium for strong bones, most plants need it for a strong structure. Calcium also builds the plant's immunity against disease, helps its cells process nutrients, and promotes overall healthy plant development. One sign of calcium deficiency is stunted and deformed stems and leaves, particularly on new growth. In succulents, this might look like distorted, discolored, burnt, or curled leaves. 

Eggshells can be used either as a tea or as a powder to fertilize your Christmas cactus. Regardless of which method you choose, you will need to thoroughly clean and dry the eggshells. Rinse the shells or soak them while scraping out any remaining egg or membrane with your finger. Boiling the shells also is an effective way to kill bacteria. If you are making a liquid fertilizer, crush 10 to 20 dry eggshells into small pieces with a mortar and pestle or by hand. Steep the shards in a gallon of water overnight, strain, and then hydrate your Christmas cactus as needed with the eggshell tea. 

If you're making powder, grind down the shells as finely as possible using a coffee bean grinder, blender, or food processor. The powder can then be sprinkled over the surface of the soil or mixed into the dirt when you repot your Christmas cactus. For a 4-inch pot, you'd need to use 1 teaspoon of eggshell powder. As you water the plant over the subsequent months, this will slowly release nutrients into the soil. Because the ground eggshells take time to break down, use this method of fertilization every two to three months.