Christmas cactus care guide

Just received a Christmas cactus?

1. Keep it wrapped, never below 10 °C (50 °F)A plant in bud reacts to sudden change. Take the sleeve off as soon as you are inside.
2. Bright, without hot midday sunAway from heaters, vents and cold drafts. Leave it there and do not turn it while it is in bud.
3. Lift it out of the foil to waterLet it drain before it goes back. Soggy roots make buds drop.
4. Keep it evenly moistWater when the top 2 to 3 cm (0.8⁠–⁠1.2 in) is dry, then empty the saucer after a few minutes.

When and how much water

Water when the top 2 to 3 cm (0.8⁠–⁠1.2 in) of soil feels dry, until water runs out of the bottom, then empty the saucer after a few minutes. In Botanicaly’s plant data that is about every 10 days in summer and every 18 days in winter, but the soil decides.

Unlike a desert cactus, it should never dry out completely. Give a little less water in early autumn until buds appear, then keep the soil evenly moist while it is in bud and in flower, because dry soil at that stage makes buds drop.

Work out your own rhythm with the watering calculator.

Light and placement

Give it bright light without hot midday sun. An east window is ideal, or a spot within about 2 meters of a south or west window. Too much summer sun turns the segments pale or reddish.

Christmas cactus not blooming: how to get flowers

A Christmas cactus that stays green usually had too much light or warmth in the evening. Street lights, car headlights or a lamp in the room can break the long dark nights it needs, and nights that stay warm have the same effect. Feeding late into autumn also means fewer buds.

Flower buds form in autumn, when nights get long and cool. Either one works, and both together work best:

From mid-September or early October, give it about 14 hours of complete darkness every night for six weeks, for example from 18:00 to 08:00 in a spare room with the lights off, a closet or under a box. Street lights and a lamp switched on for a couple of hours can stop the buds forming.

Or keep it somewhere cool, about 10 to 15 °C (50⁠–⁠59 °F) at night, for about six weeks. At those temperatures it sets buds even with normal day length.

Water a little less during these weeks, and do not feed.

Buds usually show after three to four weeks. Once you see them, bring it into normal room warmth and keep the soil evenly moist.

Then leave it where it is. Moving or turning a plant in bud is a common reason the buds drop.

Why the buds fall off

Buds fall when something changes suddenly: a cold draft, a heater or vent nearby, a move to a new room, soil that dried out, or soggy roots. A plant with a great many buds may also shed a few on its own. Find a steady, bright spot before the buds open and keep it there.

Christmas vs Thanksgiving vs Easter cactus

Three holiday cacti are sold under similar names. The edges of the flat stem segments tell them apart better than the calendar does.

Thanksgiving cactus (Schlumbergera truncata) has two to four pointed, claw-like teeth along the edge of each segment. It flowers from late November, about a month before Christmas cactus, and the anthers at the tips of the stamens are yellow.

Christmas cactus has rounded, scalloped segment edges and purplish-brown anthers. It flowers about a month after Thanksgiving cactus. Most plants sold as Christmas cactus in shops are really Thanksgiving cactus, and both take exactly the same care.

Easter cactus (Rhipsalidopsis gaertneri, also sold as Hatiora) is a different plant. Its segments are the most rounded of the three and edged with tiny soft bristles. It sets buds as the days lengthen in late winter and flowers from late March to May with flat, star-shaped flowers. It is fussier than the other two and drops segments if it gets too much or too little water.

After flowering

From late January to late March, let it rest a little cooler, about 12 to 15 °C (54⁠–⁠59 °F), and water less, letting the top few centimeters dry between waterings. In spring, prune it, repot if needed and start feeding again. It can spend the summer outdoors in a sheltered, shady spot, out of full sun and safe from slugs, as long as it comes back in before nights drop below 10 °C (50 °F).

When flowering ends, the faded flowers shrivel and drop, or you can twist them off gently. That is the end of the season, not a sign of trouble.

Do not expect a new round of buds soon. The main flowering comes after the long or cool autumn nights described in “Christmas cactus not blooming: how to get flowers”, so the work toward next winter’s flowers starts in September or October, not now.