Why have my Christmas cactus leaves turned red? The 4 possible reasons and how to fix each of them

Christmas cacti are famous for their beautiful blooms. This festive plant is a relatively easy houseplant to take care of, but that doesn’t mean problems can’t arise. One of the most common problems is Christmas cactus leaves turning red, but why does this happen?

Caring for a Christmas cactus is one of the most important things you can do if you want to ensure your plant stays healthy over the festive period. The leaves of your cactus turning red is an indicator of stress - typically triggered by too much sunlight, extreme temperature changes, lack of nutrients, or underwatering.

According to the experts, these are the four main causes and below we've outlined the simple fixes for each that you can do to return your cactus to its usual green hue.

1. Too much sunlight

'Too much exposure to direct sunlight or bright, intense light can cause the leaves to turn red. Christmas cacti naturally thrive in indirect light conditions at home,’ says Jo Lambell, founder of Beards & Daisies.

The fix to this is easy, simply move your Christmas cactus. These plants are best suited to north or east-facing windows as there is less direct sunlight.

2. Exposure to cold temperature

‘If your cactus is exposed to cold temperatures for too long, particularly below 10°C, it can cause stress, leading to reddening leaves,' says Jo from Beards & Daisies.

Graham Smith MCIHort a gardening expert at LBS Horticulture agrees. 'Fluctuations in temperature can cause the leaves of the cactus to turn red, so ensure that the plant is placed somewhere where it will receive bright, indirect light and the temperature will remain consistent (between 15 and 24°C). Ideally, the plant should not be placed close to a heat source or somewhere draughty,' he recommends.

3. Lack of water

‘A lack of water can stress your plant, causing red pigmentation to appear as it tries to save as much energy as possible,' says Jo.

If you’re wondering how often you should water your christmas cactus, the answer is every two weeks - or when the soil feels dry to the touch.

Graham points out that 'overwatering can also cause stress to a Christmas cactus and make its leaves turn red. Check that the soil of the plant is well-draining, and water when the top inch or so feels dry.'

4. Lack of nutrients

‘If your Christmas Cactus isn't getting enough essential nutrients, particularly phosphorus (an essential mineral), its leaves may turn red. This happens because the plant struggles to photosynthesize effectively.’

As a fix, Graham recommends regularly feeding your Christmas cactus through the growing season to prevent nutrient deficiencies.

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By adopting these changes, you can enjoy a beautiful healthy plant for plenty of festive seasons to come.