Key Points
Christmas cactus like well-draining, rich, slightly acidic soil.Coffee grounds added to soil may retain too much moisture retention, causing root rot.Well-composted, dry coffee grounds should only be used in moderation.
Christmas cactus are houseplants loved for their evergreen foliage and colorful blooms. Since they don’t always bloom reliably every year, and have somewhat tricky care needs, houseplant mavens often seek tips to encourage Christmas cactus to bloom, and to keep them healthy and thriving, including the best light exposure, and tips on watering and soil amendments.
Coffee grounds are often used as a soil amendment for houseplants, to increase acidity and improve texture. But when we asked plant pros if they’d recommend adding coffee grounds to the soil of Christmas cactus plants, we were surprised to learn they didn’t recommend it. They also shared some other advice on caring for these popular plants just in time for the winter season.
Meet the Expert
Rhonda Kaiser is a Master Gardener and landscape designer and the author of the book The Vintage Farmhouse Garden.
Kelly Funk is a gardening pro and president and CEO of Jackson & Perkins, an online nursery and gardening supply company.
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Use Coffee Grounds in Moderation
As its name suggests, Christmas cactus (Schlumbergera x buckleyi) is a succulent, and prefers good drainage, so it needs a well-draining potting mix and a pot that drains well. Overwatering can be an issue for these plants, and the proper soil mix can help them avoid becoming waterlogged, which may lead to root rot.
Master gardener and plant expert Rhonda Kaiser agrees that coffee grounds can be beneficial used in gardening soil. However, she says coffee grounds are “not my preferred choice for Christmas cactus.”
She says this type of compost material can retain high moisture levels, which might cause soil to become packed and dense. Kaiser notes that such soil conditions can increase the risk of root rot, which she says is a real concern for Christmas cactus.
In nature, Christmas cactus tend to grow in crevices where there is some decaying plant matter, so they do best in a rich, loamy, slightly acidic potting mix.
Coffee grounds do add some acidity, but if you choose to use them, Kaiser suggests doing so in moderation, and using grounds that are dry, after they have already composted for a while.
Mixing a small amount of dry coffee grounds into the soil when repotting your Christmas cactus is a good balanced way to incorporate them with less risk of compaction. Kelly Funk, garden pro and CEO of Jackson & Perkins, recommends not having coffee grounds make up more than 1% of total potting soil volume, or using a very small amount (an 1/8th of a teaspoon) of composted, dry coffee grounds as a top dressing.
The Best Soil Amendments for Christmas Cactus
A proper mix of soil is crucial for many houseplants, especially somewhat finicky plants like Christmas cactus. Funk recommends replacing soil when repotting Christmas cactus, which should be done every three years or so, or sooner if the roots appear to be mushy. This plant doesn’t mind being slightly rootbound, as long as the surrounding soil still absorbs and drains properly.
She suggests a basic soil mixture formula for Christmas cactus to help them thrive, starting with 50% good quality potting soil. Then she recommends adding 25% perlite to improve drainage and prevent soil compaction, and 25% bulkier materials such as coconut coir, shredded pine bark, and/or orchid bark, all of which retain moisture without becoming soggy and break down to provide nutrients.
Additional Care Tips for Christmas Cactus
Christmas cactus can be somewhat finicky plants to care for, so it’s important to get their care needs right. They prefer indirect light, and regular but light watering, and misting is not necessary. Funk suggests watering only when the top inch of the soil surface is dry to the touch, and placing a pebble tray nearby for added humidity if the indoor air is very dry in winter.
These plants also like to remain relatively undisturbed during their bloom cycle, so Funk says you should try to avoid moving them or exposing them to any sudden changes in light or temperature at this time. Avoid placing your Christmas cactus in a spot that is near a cold draft or a heating source.
Both our experts recommend a dilute, balanced fertilizer to nourish your Christmas cactus. This should ideally be done in spring, and again in early summer, but not during the winter bloom season.
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