By Jerry Meislik  (Whitefish, Montana)

The Importance of Light for Indoor Bonsai Growers

           Knowing how to water a bonsai is critical. Most bonsai die in the short term due to poor knowledge of proper watering. Under or over watering are both detrimental to proper bonsai health and survival and in fact a bonsai can be killed in only a week or two of poor watering.  In the longer term light comes to the forefront. Light is the energy source for all of a plant’s functions. The basic metabolic mechanisms of life including respiration, growth, flowering etc. are all fueled by light. Light and not bonsai “food” is the key factor. I have been growing plants indoors for about 30 years. In the last half of that time I have used metal halide light supplementation along with window light.

My indoor growing room and metal halide lights

           Plant food while providing the basic blocks for forming plant tissues, enzymes etc. does not provide energy to drive these processes. Plant food only provides the minerals needed by the plant to build tissues and to perform its metabolic processes. Plant food is not the same as “people food”; people food provides energy as well as the minerals and nutrients needed for animal life.

           If a photosynthesizing plant does not have adequate light it draws down its energy reserves stored in branches, trunks and roots to provide the power to fuel its needs. Eventually these reserves are depleted and the plant dies. This decline can be slow and plants rarely can survive as long as a year or two in dim light conditions.


            The plant on left is a Ficus benjamina 'Too Little' under indoor low light conditions. Plant on right is the same cultivar grown under high light conditions. The increase leaf mass, and twig density on the right are signs of more health and vigor.

             Light of the proper wavelength, duration and intensity are needed to maximally drive photosynthesis. Plants grown outdoors generally have adequate sunlight and the bonsai will thrive. In some areas the sun may be too bright and this actually burns the plants. This can occur with plants that are not adapted to full sunlight, as with indoor bonsai moved directly to full sunlight or growers in high temperature desert growing areas.

             It is necessary to realize that bonsai traditionally were all grown outdoors. China, the originator of bonsai, and later Japan which popularized bonsai in the west grew their plants outdoors and never indoors. Their selection of materials included temperate species like pines, junipers, and maples. These plants will not grow in a typical home environment as they require cool dormant periods. Growing bonsai indoors is a much more recent phenomenon and plants that can be grown indoors are few and far between. These are typically tropical or sub-tropical species and then only those with low light tolerances.

            Tropical/sub-tropical plants can be grown indoors, outdoors or a period of time indoors and outdoors. Growers of tropical/indoor bonsai grow their plants outdoors in tropical areas. Northern growers can keep their bonsai outdoors in the warmer months to benefit from sunshine and rain and move their plants indoors for the cooler months. Most tropical and sub-tropical species must be kept above 50-55F or the plants will suffer. Many growers because of unsuitable location, lack of outdoor growing areas, or for security reasons keep their trees indoors 365 days a year. Fuku-Bonsai has devoted its business to easing the burdens for full time indoor growers.

            Plants vary in their tolerance to low light. Most species require rather high intensity light. Indoor light is often too dim to allow most plants to survive. Giving plants access to southern and western light exposure often is helpful but many indoor growers still have light that is too dim for many plants to thrive. Fuku-Bonsai has pioneered True Indoor Bonsai, using selected clones of Schefflera that can thrive in most home environments without supplemental light. However, even low light trees will have stronger growth, faster maturation, heavier trunks and denser foliage if artificial light supplementation is used.

            Most economical are fluorescent lights easily obtained at most home supply stores. Two to four foot fluorescent lights kept as close as possible to the trees is really helpful. A simple electric timer set for an 18-hour day simplifies the setup. Normal daylight and warm daylight fluorescent bulbs will work nearly as well as special costly plant bulbs.

Simple cart with two foot fluorescent light fixture

           Compact fluorescent lights can be used if there Is only one tree to illuminate but their light is too focused to grow more than one or two plants.   Incandescent bulbs are inefficient, producing lots of heat and relatively little useable light.  Higher intensity lights such as metal halides can provide even brighter light that will allow high-light requiring plants to be grown. These lights are costly to run and are quite warm.

Metal halide light allowing high light requiring plants to be grown indoors

              LED lights are becoming more available for growing plants. They have higher initial costs vs. other lights and may one day become the standard for growing plants. Their initial cost will be paid off over time because of lower electrical consumption. Some LED lights may in fact have poorly balanced frequencies for plant growing. For more information on LED grow lights, go to  and

Home made LED light board

                Successful indoor growers must select plants that will tolerate home growing conditions or modify the home conditions to suit the selected bonsai plants. Plants that tolerate normal home conditions are very limited and Fuku-Bonsai has selected plants and clones that can succeed indoors.


                EDITOR NOTE:  Author Jerry Meislik is a rare bonsai hobbyist who has a strong understanding of the various aspects of bonsai.  He has been a friend, a minor Fuku-Bonsai stockholder,  and one of a relatively small group of bonsai hobbyists who are very involved. He is a travelling instructor who is continually researching and gaining knowledge which he generally shares with bonsai publications and his circle of correspondents and contacts.  The very nature of bonsai requires long-term planning to be able to manage a bonsai collection.  Jerry is limited in the number of trees that he can personally train but also by the capacity of his growing area.  So he's very selective when he acquires new trees and may do so only if he also culls out or removes plants. Like others, we are both developing long-term plans where our personal collections will go. 

               Jerry has grand bonsai goals and is seriously involved in the Bonsai Gardens at the Matthaei Botanical Gardens in Ann Arbor, Michigan as an educational display repository for high quality memorial bonsai. We believe that this is the future of bonsai as in American,  it is less likely that our family heirs will assume responsibility into moving a major bonsai commitment into future generations as is expected in Japan where bonsai nurseries can pass down through several generations. But even in Japan, there is a growing trend to create public bonsai gardens as major bonsai collections are increasingly broken up and sold upon the passing of prominent bonsai collectors and hobbyists.  Jerry's is one of the largest and highest credibility bonsai websites and is highly recommended.

               Fuku-Bonsai, its collection, and all bonsai resources will likely be controlled by the Mid-Pacific Bonsai Foundation and its our hope that they become the largest Fuku-Bonsai stockholder with its board of directors having a major say in running the for-profit Fuku-Bonsai Inc. in a manner that will benefit bonsai, our staff, the Hawaii visitor industry, and the Big Island community.  We invite everyone interested in participating in our future to write to founder David W. Fukumoto at


The Mid-Pacific Bonsai Foundation Journal of Tropical and True Indoor Bonsai is published monthly by email and is a benefit of Foundation membership.  Annual dues are just $12 per year.  For more information about becoming a member, go to