It may be hard to believe, but beautiful holiday cactus blooms begin in summer. So the way you treat your Christmas or Thanksgiving cactus now is vital for strong, long-lasting plants that produce tons of colorful flowers at the end of the year.
August is the last month before you have to start giving your holiday cacti special care to encourage flowering. There’s no need to move them into the dark quite yet – save that for September – but there are a handful of key tasks to do now to get them ready for next month.
I’ll walk you through how to care for holiday cacti in August to ensure your plants are bursting with bright blooms for Thanksgiving and Christmas. Plus, I’ll reveal the number one summer care mistake that can ruin flowering.
1. Provide Bright, Indirect Light
Light is the key to making a Christmas cactus bloom. These unique plants need 12-14 hours of total darkness in the fall in order to form flower buds. This light and dark period mimics their native environment and forces the plant into blooming. But don’t put your holiday cactus in the dark just yet!
In August, holiday cacti still need bright, indirect sunlight. Place your Christmas or Thanksgiving cactus in an east-facing window or behind a sheer curtain on a south or west-facing windowsill. If you moved your cactus outdoors for summer, make sure it’s not getting too much light as the sun shifts throughout the season. Too much sunlight can end up turning Christmas cacti foliage purple or reddish.
2. Fertilize Before Buds Form
August is a good time to give your Christmas or Thanksgiving cacti a dose of bloom-boosting fertilizer. This plant food from Amazon is made specifically for Christmas cacti and is heavy in phosphorus, which encourages flowering.
Fertilizing holiday cacti now provides them with the essential nutrients for buds to form before you begin forcing buds in the fall. This should be your last feeding for a while. Don’t fertilize Christmas cacti while they’re forming buds and blooms in fall and into winter.
3. Slowly Cut Back on Watering
In August, you still need to water your Christmas cactus regularly so the soil remains moist but not soggy. However, as the month goes on and plants get closer to bud formation time, you can start cutting back on how much you water.
If you moved your Christmas cactus outdoors for the summer and it’s still outside during the month of August (which is totally fine), you shouldn’t cut back on watering quite as much as if your plant was indoors. Container plants dry out faster outdoors in the summer heat and wind, so keep an eye on plants to make sure they’re getting enough moisture. You can use a simple soil moisture meter from Amazon to check if your plant needs more water.
The #1 Summer Mistake
There is one task you should take off your to-do list this month. Don’t repot your holiday cactus right now. Christmas and Thanksgiving cacti are plants that actually prefer to be root bound, so they don’t often need repotting – only once every 3-5 years or so.
Repotting Christmas cacti in late summer or early fall is also the wrong time for this task, even if your plant does need a bigger container. It may seem logical to move them into a new pot when you bring your plant inside around this time of year, but it can cause too much shock to your cactus just as it needs to store up its energy for blooming. Plus, root bound plants flower better.
The best time to repot plants is right after blooming. Wait until the end of the holiday season to move your cactus into a bigger pot. Only increase the pot size by 1 inch (2.5 cm) in diameter and use a well-draining cacti potting mix, like this one from Miracle-Gro.
