Can You Grow Dragon Fruit Cactus Inside?
You can grow the dragon fruit plant (Hylocereus undatus) indoors if your home has a location with plenty of sunlight, such as a sunroom or a large window where the plant gets six to eight hours of sunlight. To make an indoor dragon fruit cactus bear fruit might require hand-pollination, a job that is done by moths, bats, and bees outdoors. Dragon fruit cactus is a vine that can grow up to 20 feet tall. Varieties suitable for indoor growing include ‘Edgar’s Baby,’ ‘Alice,’ ‘Seoul Kitchen,’ ‘Yellow Dragon Fruit,’ and ‘Zamorano.’
How to Grow Dragon Fruit Cactus Indoors
As a climber with aerial roots emerging from its branches and latching onto objects, the plant needs support to grow upright, such as a trellis. Make sure that it is sturdy and strong enough to support the branches with fruit, which can get heavy.
Sunlight
Dragon fruit cactus needs six to eight hours of full sunlight per day to develop flowers and fruits. Morning sun from an east-facing window and evening sun from a west-facing window is ideal. If your window is south facing, the light might be too intense and scorch the plant, especially in the summer. One workaround is to rotate the plant 180 degrees at regular intervals, so it gets even sun exposure on all sides.
Artificial Light
Instead of six to eight hours natural light year-round, you can use supplemental grow lights. To mimic strong sunlight, they should be full-spectrum LED lights. Gradually adapt the plant to the light, especially if it has been in the shade for a while, for example during shipping. Start by placing the light about 30 inches away from the plant and move it closer over the course of a few days.
Temperature
The ideal room temperature is between 65 and 85 F. The plant does not tolerate temperatures over 100 F and should not be kept in rooms that get overly hot during the summer. The dragon fruit cactus is not frost-tolerant. During winter, keep it away from cold windows.
Humidity
Usually, 30% to 50% room humidity is adequate for the dragon fruit cactus. During the heating period in the winter, place a humidity tray with pebbles nearby, use a room humidifier, or mist the plant from up above.
Watering
Water dragon fruit cactus carefully, as the plant is very sensitive to overwatering but can withstand some dry conditions, as its phylloclades—the leaf-like branches—retain water. During the active growing season in the summer, water when the top of the soil feels dry. In fall and winter, cut down on the watering, which induces plant dormancy.
Air Circulation
Dragon fruit cactus is a vigorous grower that needs to be cut back and thinned out at least once a year to ensure good air circulation. Poor air circulation makes it more prone to fungi.
Fertilizer
Despite it being a tropical plant, dragon fruit cactus only grows during the summer. Fertilize it about once a month with a low-nitrogen fertilizer. Too much nitrogen leads to excessive vegetative growth and should be avoided.
Pruning and Maintenance
The goal when pruning the plant is to cut it back to a single stem or a few thicker stems as the main vines. Also, thin out the smaller side branches, on which the flowers and fruit will develop. This not only improves air circulation but also increases the quality and size of the fruit.
Pollination
If the variety is not self-fertile, it needs cross-pollinating by hand with the pollen from the flower of another dragon fruit cactus. Collect the pollen from the stamen and gently dab it onto the stigma of the plant you want to pollinate. Make sure to use a fresh cotton swab for every plant. Dragon fruit cactus is a night bloomer, so you need to pollinate it between dusk and dawn.
Container and Size
Use a five-gallon container that is at least 10 to 12 inches deep, with adequate drainage holes. It is a tall plant. A container made of a heavy material such as ceramic or terracotta is better than plastic, as it is less likely to topple over.
Potting Soil and Drainage
When it comes to soil, dragon fruit cactus is a cactus in name only. It needs to be planted in nutrient-rich, neutral to acidic potting soil, and not cactus soil, as the latter does not provide enough nutrients. To improve drainage, you can add some sand to the potting soil, and place pebbles, stones, or bark at the bottom of the container.
Potting and Repotting Dragon Fruit Cactus
Repotting becomes necessary when the plant appears root-bound. Depending on the initial container size, that could be as soon as after one year. The roots of the dragon fruit cactus are very small and hairy and repotting it requires extra caution in order not to damage the roots. If you have the space to let the plant grow to its mature size, it is best to repot the plant right away in a 25- to 30-gallon size container with a depth of 20 to 24 inches, to cut down on the repeated repotting.
Moving Dragon Cactus Fruit Outdoors for the Summer
Once all danger of frost is past and the daytime temperatures are consistently above 70 F, you can move the plant to a patio, porch, or balcony. Bring the plant back inside when the daytime temperatures drop below 65 F and there is any danger of the first frost. In hot summer weather with temperatures over 100 F, the plant will suffer heat damage, and too strong sunlight will lead to sunburn. If moved outdoors for the summer, like all outdoor container plants, it requires more frequent watering than indoors.
