There are two major reasons people buy a Christmas cactus plant: Its appearance and its holiday bloom time.
The latter is often a matter of some headache since growers will often sell Thanksgiving cactus or even Easter Cactus as Christmas cactus.
The good news is, all three of these succulents are closely related, so their needs tend to be very similar.
To be safe, it’s best to know the difference:
Christmas Cactus (Schlumbergera x Buckleyi): Inheriting features of Schlumbergera russelliana, the Buckleyi group of cultivars have rounded, symmetrical teeth. They bloom in December, bearing regular flowers that hang and have pink pollen.
Easter Cactus (Schlumbergera gaertneri): This plant (and its cultivar, Schlumbergera x gaertneri) has notched, toothless margins and blooms in spring. The scarlet blooms are regular and open from a funnel shape.
Thanksgiving Cactus (Schlumbergera x Truncata): This cultivar group is based on Schlumbergera Truncata and has pointed teeth that are less symmetrical than on Christmas cacti. The flowers bloom horizontally in November, with the upper half being shaped differently than the lower hand and yellow pollen.
These differences may seem minor, but are important in getting the care details right, as well as knowing if there’s an actual problem with blooming (as opposed to just having the wrong cactus).
In the case of Christmas cacti, fertilizing is one of the more confusing parts of care, because you don’t actually feed it when it blooms, unlike most plants.
While balanced formulas work, there are some variations to this rule which are worth considering.
That said, here’s everything you need to know about fertilizing your Christmas cactus (once you’re sure that’s what you have).
Best Fertilizer for Christmas Cactus
As mentioned, you don’t actually feed a Christmas cactus when it’s blooming.
We’ll get more into detail on that, but first it’s important to have the right fertilizer picked out.
Schlumbergas are epiphytes, meaning they’re a non-parasitic plant that grows on other plants but gets their nutrients and moisture from the air.
As a houseplant, they are generally planted in soil and watered in a manner similar to other potted plants, but it’s also a lot easier to accidentally over fertilize the plant.
One of the first things you’ll need to know before picking a good fertilizer is the NPK ratio.
This represents the percentage content of the three most important nutrients: nitrogen (N), phosphorus (P), and potassium (K).
In the case of Christmas cacti, a 20-20-20 mix works best.
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You can technically get away with a 20-10-20 mix and have a perfectly healthy plant, but the results won’t be as impressive as a balanced blend.
Liquid houseplant fertilizers are generally the best choice, as these are easily absorbed and less likely to cause burns if properly applied.
Some folks swear by granular (time-release) fertilizers, but these aren’t actually as efficient because there’s no way to control the ratio of nutrients being released at any given time.
Miracle-Gro makes an excellent liquid fertilizer that’s both trusted and cost-efficient.
Just be sure to dilute, even if using the foam formula.
Likewise, Espoma puts out a very good product called Plant Food Indoor! That comes in a small bottle but dilutes into 8 gallons of completely organic fertilizer.
Beyond the basic fertilizer, you will also need to invest in some Epsom salts, as these are a wonderful way to boost magnesium for your plant (and get rid of some aches and pains in the process!) without spending a lot of money.
When or How to Fertilize Christmas Cactus
Christmas cacti bloom during their dormant phase, which can really throw people off.
They should actually be fed monthly from April through October, diluting and applying the fertilizer based on any instructions on the packaging (different brands may need to be diluted or applied differently).
Avoid fertilizing in November through March – which is when the plant actually blooms.
Never get fertilizer directly on the plant, as this can cause burns no matter how much you dilute it.
Instead, always make sure to apply the fertilizer to the soil slowly so there’s no splashing and make your way around the container, lifting the stems as needed.
As for the Epsom salts we mentioned, you will want to mix 1 tablespoon per gallon of water.
Give this to your plant once per month OPPOSITE the feeding schedule.
For example, if you fertilize on week 1, you will want to give the Epsom salts on week 3.
Fertilizing your Christmas cactus is important, but you will also need to remember a few important rules.
The first rule is that you should flush the potting soil occasionally to prevent a harmful buildup of salts.
Using the soak-and-dry method of watering will help flush out the soil automatically, but other watering methods may require a manual flushing every few months.
Christmas cacti – like all other potted plants – will need fresh well-draining soil every few years or the fertilizer won’t be enough to keep your plant healthy.
This repotting process also allows you to increase the pot size when the plant becomes rootbound.
Proper fertilizing can not only provide healthy blooms and a generally healthier plant but when part of a proper care regimen can allow your Christmas cactus to live for decades.