How to Grow Bonsai Indoors

Bonsai require temperatures above 20 degrees F to thrive.

The first bonsai trees were not the artistic creations that we see today. In fact, during the 13th century, Japanese collectors potted native trees that nature created smaller than normal. As interest in bonsai trees grew, artisans began to trim full-sized trees down to smaller versions. While bonsai tradition has always lent itself to outdoor growing, regions that experience winter temperatures lower than 20 degrees F require indoor bonsai growing.

Things You’ll Need:

• Watering can with fine spray head
• Horticultural lighting
• Fertilizer
• Insecticidal soap
• Sharp scissors
• Fungicide

1. Maintain moist soil at all times. Use a watering can with a fine spray head to water the foliage along with the soil. Allow the water to flow through the layers of soil and out the drainage holes in the bottom of the container. Water whenever the top ¼ inch of soil begins to dry out.

2. Display the bonsai in the brightest window of your home. If a bright window is not available, set the bonsai under horticultural lighting. Two 40-watt fluorescent bulbs set 6 inches above the bonsai will do an adequate job of mimicking sunlight.

3. Feed the bonsai a water-soluble fertilizer. Check the packaging label for allocation amounts and application frequency. Bonsai species appreciate fertilizing every two weeks, but do not fertilize during dormancy.

4. Allow the bonsai to enter a six- to eight-week dormancy once a year. Dormancy gives the bonsai a chance to rest and re-energize. Move the bonsai to a cool area, such as a basement, root cellar or potting shed, that has a constant temperature of between 30 and 40 degrees F. Move the bonsai back into bright light after the dormancy period.

5. Remove pests by hand or apply an insecticidal soap to the bonsai. Bonsai are prone to scale, mealy bugs, and aphids. An insecticidal soap applied according to label instructions will help kill the pests on the plant while keeping new pests at bay.

6. Prune the bonsai using a pair of sharp scissors to keep it looking neat and tidy. Wait for the bonsai branches to produce two sets of fresh leaves. Cut the branches back to one set of new leaves at the time of trimming. Never remove both sets of new leaves during a single pruning