Indoor Bonsai by Bob Fisher For those of you who are new to indoor bonsai, fortunately there are a number of goods books available including Bonsai for Indoors produced by the Brooklyn Botanical Garden. One of the key features of this booklet is a listing of 100 tropical plants suitable for indoor bonsai. Another book I have is simply called Indoor Bonsai written by Paul Lesniewicz. Also, the Toronto Bonsai Society has a number of books which have articles on indoor bonsai and they are available from our library free of charge. The T.B.S. produced a very good article on indoor bonsai by Jennifer de Four in the May 2000 edition of the Toronto Bonsai Journal. In addition, there was an article on Providing Humidity for Indoor Bonsai published in the December 2000 T.B.S. Journal. One of the best articles is in the International Bonsai magazine, Volume 22, Number 4, Issue #88 2000/No.4. The publisher and editor is William Valavanis and his e-mail address is wnv@internationalbonsai.com. Since it is obvious there is a wealth of information available for reading . . . for this discussion I will be giving you my ideas and what has worked for me, rather than giving you a dissertation of what you can read in the books. Why keep indoor bonsai? Sometimes it is out of necessity because for several years I lived in an apartment and indoor Bonsai was my only choice. Now I own a home, but I still enjoy indoor bonsai because I can work on them during the winter months, and most importantly, I enjoy bringing some of my better trees up from the basement to the family room for a day or two during the winter blahs to appreciate their beauty and tranquility. Indoor bonsai can be kept successfully in a south of west window during the winter, but come the hot summer, they should be moved outdoors, or if this is not possible, then shade them with a curtain or move them to an east window. My wife successfully keeps her ficus collection in a west window and moves them outside during the summer and has been doing this for over 10 years. My indoor collection is kept under fluorescent light stands during the winter, and then moved outside in the spring. I have two fluorescent light stands with two tiers on each stand. One stand uses 2X40 watt fluorescent bulbs on each tier, and I keep my lower light level plants such as ivy, ficus and boxwood on this stand. These stands are not cheap. I would guess the 2-light units are in the $300 range. The other stand I have is what they call an "Orchid Stand" and carries 4X40 Watt bulbs on each tier. Prices on these stands run from $300-$400, and because of the higher light levels I use this stand for my myrtle, pomegranate, bougainvillea and portulacara. Humidity is important, so make sure the humidifier is operating properly on your furnace. I have a hygrometer to measure relative humidity and it normally shows just over 50 on the scale (which is in the normal range). We also have a programmable thermostat on our furnace which turns the house temperature down to 65-deg. at night. The trees enjoy this, as it approximates the drop in night temperature in their natural habitat. I use 40-watt fluorescent bulbs with a warm white or deluxe warm white designation. There are more expensive bulbs on the market which have a higher red spectrum, but they have normally a lower light output. Frankly, I would rather have a 4-bulb orchid stand with 40-watt warm white bulbs than a 2-light stand using the most expensive 40-watt "Sho and Gro" bulbs. There are mercury vapour and metal halide bulbs available and are excellent, but are also very expensive and create difficult installation problems. Perhaps we could have a discussion on these alternative light sources at a future meeting. I do not want to get too technical in this discussion, but as a further note on fluorescent bulbs, and in fact bulbs in general, be they fluorescent, high pressure or low pressure sodium, quartz halogen or mercury vapour, be very, very aware of the "CRI" (the colour rendition of the bulb). Or, in simpler terms, the light spectrum. Light is made up of all the colours in the rainbow, and in the lighting business, this is referred to as colour rendition. The fluorescent bulbs which have worked best for me are in the 4500-6500 CRI, and this information is available from the various bulb manufacturers such as G.E., Osram, Sylvania, etc. I usually move my bonsai outdoors in mid-May when any chance of frost is over. This is the time for root pruning and repotting. In fact, it is the only time I would consider any major root pruning and/or repotting. Normally I use the same soil for both my indoor and outdoor plants. Most importantly for indoor plants, make sure your soil drains very well, as root rot is always a problem when you bring them indoors for the winter. Be careful of leaf burn in the early spring when you bring them outdoors because of the much higher light intensity outside. Normally I feed my plants with 20/20/20 fertilizer. I give full strength outdoors every 2 weeks, and one half strength indoors about every 4-6 weeks. Come the fall, I usually bring my plants indoors in mid to late september. This is a very critical time for indoor trees because they are being subjected to far lower light levels and much drier air. Consequently, when I first bring my trees inside I am very, very careful when watering. At this time and at this stage, you should be aware of the growing habits of your specific trees. Here are the observations on my plants: Ficus: Many species tend to drop their leaves (eg. Toolittle and Nerifolia) when brought indoors, so don't over-water during this period. Ficus do not like wet feet! Be cautious in watering, and in approximately two weeks buds will show and new leaves will appear in another week. Ivy: No major problems here, but they prefer over-watering rather than under-watering. Bougainvillea: Prefers to be under-watered versus over-watered. By under-watering, I mean the soil should become dry for ficus and bougainvillea. I will often do the 'finger test' - that is, stick your finger down into the soil to get an idea of its dryness. The other method is to lift the plant after watering and then lift it daily, as the lightness is a good indication of how dry it is. I use a fairly porous soil, so I water some plants daily and others get a thorough watering every two days. Boxwood: Boxwood isn't too difficult . . . just don't over-water. Pomegranate: Seems to use a lot of water, so check them daily. Myrtle Communis: This is one of my favourite plants, but also one of the most difficult. Because of its small leaf it dries out very quickly, so I would rather see you over-water rather than under-water. It is also difficult in re-potting and appears to have a symbiotic fungus growing with it, so I only change 1/2 the soil when repotting. Where to Buy Suitable Plants for Indoor Bonsai: Check our "Vendors" section on th TBS web site as well as your local nurseries for suppliers of indoor bonsai.