How to Grow a Bonsai Tree Indoors—and Actually Keep It Alive
The first time you see a bonsai tree, it's easy to fall in love. These diminutive trees are awe-inspiring. Gardeners and black thumbs alike delight in the magical quality of a tree that has remained tiny all its life.
The word "bonsai" translates to "grown in a tray or container" and it refers to any type of tree that is forced to remain miniature. The tradition dates back thousands of years in Japan, where depictions of bonsai can be seen in ancient art. Today, bonsai are popular around the world. Growing bonsai remains a specialized niche, but with the help of books, YouTube tutorials, and dozens of public collections, learning the art of bonsai is more accessible than ever. We've gathered tips for growing an indoor bonsai tree, including advice from the head curator of the celebrated bonsai collection at the Brooklyn Botanic Garden. Here is the best advice for how to care for a bonsai tree indoors—and actually keep it alive!
Pick your plant carefully
The art of bonsai was traditionally practiced on hardy plants outdoors, which is part of the reason they have a reputation for dying indoors. "Tropical bonsai, such as ficus, schefflera, dwarf jade, and serissa, are the best bonsai for the beginner," says David Castro, the curator of the Brooklyn Botanic Garden's bonsai collection. "If you can take care of houseplants, then you have a good chance of keeping tropical bonsai happy, healthy, and alive."
Skip the evergreen bonsai indoors
Many other bonsai, including evergreens like juniper, pine, and spruce trees will not thrive in an indoor environment. "Common garden juniper bonsai that are potted up and typically styled with a curved shape are not, I repeat, not indoor trees!" says Castro.
Shop at a bonsai specialist
When figuring out where to buy a bonsai tree, it's wise to seek out a nursery that specializes in bonsai (there are more than 100 in the U.S. alone). Castro notes that specialized bonsai nurseries tend to do most of their business from their websites and by appointments to their facilities. Castro also encourages shoppers to avoid what he calls "mall-sai" trees (bonsai trees found in shopping malls and big box stores). "They look tempting and inexpensive, but they are potted up in a very cheap soil mix, with decorative pebbles glued to the top of the soil," cautions Castro.
Position your plant in the light
Find a place for your bonsai in an area of the house that has plenty of bright, indirect sunlight. Be alert that many spots immediately adjacent to windows are problematic: Direct sunlight is too harsh, and bonsai should be kept away from cold drafts and also from direct heat from radiators, which are often positioned below windows.
Keep it moist
Gauge your bonsai's water needs the way you would with any other plant: Poke your finger in the soil. If it feels dry, water thoroughly. Ideally, you want to water just as the soil begins to lose its dampness, which might be every day during the growing season and every other day or even less frequently when the tree is dormant in winter. Castro also recommends misting your tree daily.
But don't overwater!
While sufficient watering is key for a plant in such a small container, overwatering is one of the most common bonsai killers! If you notice the leaves yellowing or turning black at the tips, it's possible the roots are drowning. Let the plant dry out completely, then rewater again and allow the plant to dry out partially before the next watering. If the problem persists, the soil may not be draining well and you'll want to try repotting.
Repot with confidence
Bonsai need repotting every year to three years, depending on the plant, so you shouldn't need to do this right away. However, if your bonsai was sold in a pot without drainage holes, you should repot it into one that has them as soon as possible. You'll need to buy or mix free-draining soil for the new container. Eric Schrader, a bonsai expert in San Francisco, recommends the popular mix of one-third each of pumice, scoria (lava rock), and akadama (a claylike particle mined in Japan). He notes the size of the soil "rocks" should be relative to the size of the container or plant. When you water the tree, the water should go straight through the soil.
Fertilize if growth weakens
Bonsai, while tiny, are still trees, so they get most of their nutrients from the sun and air. However, because bonsai are confined to a tiny container with low-nutrient soil, they will eventually need fertilizer to replenish their soil. In The Little Book of Bonsai, author Jonas Dupuich recommends looking for fertilizers with nitrogen, phosphorus, and potassium (N-P-K) with up to 5 to 6 percent of each nutrient.
Don't go bananas with the tools
To maintain a bonsai, some books will tell you, you need a list of two dozen tools, but for the beginner starting out, you need a pair of pruning scissors, like ARS Steel Blade Cultivation Scissors, and tweezers to remove dead leaves and tiny weeds. "Over time, you can acquire tools made specifically for bonsai that are designed to help you work quickly and comfortably," Dupuich writes.
Take a bonsai class!
Before you go in for your first extensive pruning or a big repotting project, the experts recommend seeking out a class—either online or in person. There are more than 200 bonsai clubs in the United States that host workshops. Online, your options are endless.
"The biggest lesson we learn from the bonsai hobby is patience," says Castro. "Let it grow. Do not be in a rush to try things that have taken seasoned hobbyist years to learn." He adds: "The rewards of keeping a bonsai are personally invaluable to your soul and wellbeing under these stressful days."