Don’t be fooled by the name, the Christmas cactus (Schlumbergera) isn't actually a desert plant at all. Originating from the coastal mountain rainforests of Brazil, it grows on tree branches and shady rock ledges rather than in sand and scorching sun. This means that caring methods differ greatly from the spiky cacti you might keep on a sunny windowsill.

It's made up of flattened, segmented stems that arch outwards and, in late autumn, the tips of those segments produce buds that open into tubular flowers in shades of pink, red, white, orange and purple. The challenge when growing a Christmas cactus doesn’t come from keeping it alive, but getting it to flower at exactly the right moment. While Christmas cacti usually bloom between November and January and are known for their festive colours, if the right care is provided, a Christmas cactus should be able to bloom again in spring, so it’s important to take proper care of them.

Mistake #1 - Overwatering

It’s important to ensure you’re watering a Christmas cactus, as these plants need moist soil to thrive, so it’s recommended to water them at least once a week once the top inch or two of soil is dry - meaning you can sometimes wait up to 2 weeks to water it again!

Make sure the soil is dry before watering each time as the roots and bottom of the Christmas cactus can start to rot with an excess of water, which can also lead to fungus gnat infestations. Check out our guide on getting rid of fungus gnats for more advice if this does occur.

However, a Christmas cactus is a succulent, and often grows better when bottom-watered. To do this, simply place your Christmas cactus in a container that can hold enough water to cover half of the pot. 

Leave it there for around 5-15 minutes or whenever you can see that the top layer of soil is moist, and ensure that you allow the Christmas cactus to sit for a couple of minutes to allow it to drain any excess water out before putting it back in its outer pot to avoid root rot.

Mistake #2 - Choosing the incorrect soil

Using the correct soil is also important for the growth of your Christmas cactus, and using the incorrect mixture can affect growth, as well as causing other problems such as rotting the roots and stems quicker.

Use some decomposed compost or peat, as well as some gravel, sand, or coarse perlite, to help with airflow and water drainage.

Mistake #3 - Incorrectly potting and repotting

Picking the right pot for the Christmas cactus is important, and you must make sure to repot it over the years to ensure it has enough room to grow, and avoid becoming root-bound.

If it does look like it’s drooping, or falling to the side, then it’s telling you it’s too big for the current pot, and needs to be changed to a larger one.

When it comes to Christmas cactus repotting, this should be done after it has stopped blooming and the flowers have wilted - typically in late winter or early spring.

Remove the plant from its pot, along with the surrounding soil ball, and gently loosen the roots. If the potting mix is compacted, gently wash it away from the roots with a little water.

Put the Christmas cactus in a new, larger pot so the top of the root ball is about an inch below the rim of the pot. Then, fill around the roots with fresh soil and pat gently to remove any air pockets inside. Continue to water as usual.

Mistake #4 - Not giving it enough light

A Christmas cactus will be far more likely to bloom when it’s kept in the optimal conditions, and despite its festive, wintery name, it will need lots of bright indirect sunlight, relatively humid conditions, and warm temperatures.

The cactus will need around 4-8 hours of bright, indirect sunlight, followed by a period of continuous darkness - ideally around 13 hours.

The best place to locate your Christmas cactus is in a place with indirect sunlight, such as an east-facing window or even a bright bathroom. However, if you’re keeping your Christmas cactus in the bathroom, ensure to move it to a darker place at night. Alternatively, you can place it in a room that doesn’t see the sun in the evening.

When following this process, flower buds will usually begin to show in around 6 weeks, at which point you can put the Christmas cactus back on display - still avoiding direct sunlight however, as this could scald the leaves.

Mistake #5 - Not using fertiliser

It’s equally as important to feed your Christmas cactus with a premium fertiliser, or a 20-20-20, or 10-10-10 plant food diluted with water, to ensure it receives all the necessary nutrients it needs to grow.

A balanced fertiliser will have an equal ratio of the main three nutrients for plants on their packaging - nitrogen:phosphorus:potassium, or N:P:K. 

A Christmas cactus requires more magnesium than other plants, so you can also use magnesium sulphate, such as Epsom salt, mixed with water, to add more nutrients to your cacti.

We want our plant to last beyond the big day, so knowing how to care for your Christmas cactus through the rest of the year is crucial.

Follow these tips for best results:

• Light: Find a bright spot with indirect sunlight. East or north-facing windowsills will work nicely. Strong sun through glass can scorch the segments and turn them red.
• Watering: Watering Christmas cactus correctly is where most people slip up. Unlike a desert cactus, it likes its compost kept lightly moist during spring and summer. Water when the top couple of centimetres feel dry, let the excess drain away and never leave the pot standing in water. Ease off the watering as autumn arrives.
• Temperature: During growing season you’ll want to keep the temperature between 18 and 24°C. The biggest issue you might face is central heating, keep it well away from radiators, as well as cold draughts from doors and windows.
• Feeding: A balanced houseplant feed once a month from spring to late summer is plenty. Stop feeding by early autumn, as this helps nudge the plant towards flowering rather than leafy growth.

This is what is key to understand in order to get your timing just right. Christmas cactus (Schlumbergera) sets its buds in response to two things: shorter days and cooler nights. Give it both for around six to eight weeks and it will reward you with a mass of buds.You’ll want to start this from mid to late October and this will get your buds showing by late November and open flowers by Christmas week.

Follow these tips:

• Place in a cool spot. Somewhere unheated where night temperatures sit between 10 and 15°C is ideal. If that's not possible, simply move it to the coolest room you have.
• Give it 12 to 14 hours of darkness. From early evening until morning the plant needs complete, uninterrupted darkness. Even the light from a television can interrupt this, so if needed, pop a cardboard box or a dark cloth over it and remove it again in the morning.
• Keep the days bright. Short days, not dark days. During daylight hours it should still get plenty of indirect light.
• Reduce watering. Water sparingly during this period, just enough to stop the segments shrivelling.
• Stop feeding entirely.

If you follow these caring instructions you should start to see pea sized buds forming at the tips of the segments. When this happens, bring the plant back into a warmer, bright spot, return to normal watering and resist the urge to move it or even turn it towards the light. A half-strength high-potash feed (tomato feed works well) every couple of weeks will help the buds develop.

The most common Christmas cactus problems can usually be fixed pretty easily, see below:

• Buds dropping off: The most common complaint. It's almost always caused by a sudden change in conditions once buds have formed, such as moving the plant or a blast of heat from a radiator. Avoid this by keeping conditions as consistent as possible once those buds appear.
• Limp, wrinkled stems: This usually points to overwatering and root rot rather than thirst. Check the roots and, if they're brown and soft, repot into fresh houseplant compost mixed with a few handfuls of grit or perlite.
• Red or purple segments: A sign of stress from too much direct sun or very cold conditions. Move it somewhere brighter but out of direct light.
• No flowers at all: Nine times out of ten the plant is simply too warm at night or is getting light in the evenings. Even a lamp in the corner of the room can be enough to interrupt its dark period.

Once the last Christmas cactus flower has dropped, let the plant rest. Cut watering right back for around six weeks and keep it cool and bright. In spring, pinch or twist off a segment or two from the end of each stem to keep it bushy; those pieces will root easily in a small pot of gritty compost if you'd like more plants to give away. Repot every two to three years into a pot only slightly larger than the last, as it flowers best when its roots are a little snug.

A Christmas cactus is one of the few houseplants you can genuinely schedule. Give it cool nights and long, dark evenings from now until late November, keep the watering light and leave it well alone once the buds appear, and you'll have a windowsill full of colour just as the decorations go up.

Better still, with a little care through the rest of the year, the same plant will do it all over again next December, and for many Decembers after that.