How often should I water my Christmas cactus?

If you are wondering how often you should water your Christmas cactus, it's likely that you're new to caring for this festive staple, and haven't quite got its watering routine right yet.

The signs you're getting it wrong? Overwatered Christmas cacti go limp and the leaves might yellow; underwatered Christmas cacti might shrivel and go brown.

As a rule, Christmas cacti only need watering every two to three weeks. However, knowing when to water Christmas cactus and when to hold off can vary household to household.

The crucial factors that will help you pin down exactly how often to water your Christmas cactus are listed below, with advice from top plant experts. 

How often should I water my Christmas cactus?

The secret to growing Christmas cactus successfully is getting the conditions just right. Your watering routine is an important part of this, and doing this every 14 to 21 days should guarantee a healthy plant. However, these are the factors which might affect how you adjust your watering schedule.

1. Every 14-21 days when conditions are right

Ensuring the potting soil is well-draining and loose will mean that you can stick to the 14-21 watering routine for your Christmas cactus. 

'A blend of two parts compost, with one part fine bark and one part grit or pumice, will ensure no excess moisture or residue hangs around the delicate roots after watering,' say Keira Kay, Bloom & Wild's plant expert.

'Christmas cactus likes its soil to be gently moist,' continues Rachel Martin, of Patch Plants.

The size of your container, the light levels and room temperature can also affect how healthy your Christmas cactus will be and how often you will need to water it. 

'Holiday cacti grow best when they are placed in a location with partial shade, such as an east or west facing window, with a temperature between 70° and 80℉,' say the plant experts at the University of New Hampshire. 'Exposure to too much bright sunlight, especially in the summer months, can burn the foliage and not enough light can slow growth and cause the soil mix to dry too slowly. When in doubt, err on the side of under-watering as opposed to over-watering.'

2. When the top half of the soil feels dry

Christmas cacti aren't dessert cacti, but tropical forest cacti, so they shouldn't be treated as drought-loving.

'Your Christmas cactus needs watering once its soil feels dry,' house plant expert Jo Lambell, founder of Beards and Daisies and author of The Unkillables advises, who suggests performing the finger dip test: 'Pop your finger into the soil and if it feels dry, then it’s time to give your plant a drink.'

3. Not at all while the pot is waterlogged

The ideal when watering your Christmas cactus is to soak the soil and allow the water to run through and out of the bottom of the pot. Once that's done, ensure the cactus does not sit in water; allowing it to do so will over-saturate the roots, which will make them liable to rot. 

If you discover that your Christmas cactus has been sitting in water, lift it out of the pot, snip off rotting roots before washing the remaining roots. Then repot and allow the plant to dry out a little, before performing the finger dip test ahead of watering again.

What does an overwatered Christmas cactus look like?

Signs that your Christmas cactus is overwatered are black or red spots, yellow leaves and a limpness to the plant that's noticeable. If the roots are sitting in water, this is also a sign of overwatering. 

How do you tell if a cactus is underwatered?

Wrinkled, calloused and puckered leaves, and discoloration (browning) are all signs of a Christmas cactus being underwatered.