bonsaiTALK Community - View Single Post

Jerry's site, the link in the previous post, is excellent and I encourage you to read it. His setup is pretty complicated, though, and not what most people can accomplish. Even so, I dream about a setup like his. Anyway, to answer your question:

The distance depends on what your artificial light source is. Factors to consider are heat output and light intensity. If it is a metal halide, it should be quite a distance away or you will burn foliage with the heat it produces. Most incandescent light sources produce heat.

The problem is, the farther away you move the light source from the site of photosynthesis (each leaf), the lower the light intensity on the leaf. In fact, it is an exponential relationship. Therefore, you need to keep your plants as close as possible to the light source without burning them.

Fluorescent light is a good compromise in that it produces much less heat than incandescent, and therefore you can place your trees quite close to the bulbs without fear of damage. I use 4-foot shoplights with GE Daylight bulbs which have a color temperature of 6500 K, or just a bit bluer than midday sun. I supplement these with "twisty" compact fluorescent bulbs (incandescent replacement bulbs that fit into normal, "screw-in" sockets) for more intensity. I place three shoplights side-by-side which gives me a bank of six bulbs. You can find similar set-ups intended for indoor growing, but they will usually be more expensive, compared to $8 for a pre-wired shoplight. I can place my trees within an inch or less of the bulbs and have no damage.

This setup is in an area of my basement that receives no natural light, and yet I find that my trees winter quite well there. That is, as long as I don't prune or pinch heavily, which will result in new, leggy growth. This is because even with all that light, it still isn't even close to what the sun provides. If you like, I'll try to get a photo of the setup for you.

30-Oct-2007	#4
Salvelinus Bonsai Remedial Join Date: Dec-2003 Location: Cincinnati Country: USA USDA Zone: 6a AHS Heat Zone: 6 Posts: 108	Jerry's site, the link in the previous post, is excellent and I encourage you to read it. His setup is pretty complicated, though, and not what most people can accomplish. Even so, I dream about a setup like his. Anyway, to answer your question: The distance depends on what your artificial light source is. Factors to consider are heat output and light intensity. If it is a metal halide, it should be quite a distance away or you will burn foliage with the heat it produces. Most incandescent light sources produce heat. The problem is, the farther away you move the light source from the site of photosynthesis (each leaf), the lower the light intensity on the leaf. In fact, it is an exponential relationship. Therefore, you need to keep your plants as close as possible to the light source without burning them. Fluorescent light is a good compromise in that it produces much less heat than incandescent, and therefore you can place your trees quite close to the bulbs without fear of damage. I use 4-foot shoplights with GE Daylight bulbs which have a color temperature of 6500 K, or just a bit bluer than midday sun. I supplement these with "twisty" compact fluorescent bulbs (incandescent replacement bulbs that fit into normal, "screw-in" sockets) for more intensity. I place three shoplights side-by-side which gives me a bank of six bulbs. You can find similar set-ups intended for indoor growing, but they will usually be more expensive, compared to $8 for a pre-wired shoplight. I can place my trees within an inch or less of the bulbs and have no damage. This setup is in an area of my basement that receives no natural light, and yet I find that my trees winter quite well there. That is, as long as I don't prune or pinch heavily, which will result in new, leggy growth. This is because even with all that light, it still isn't even close to what the sun provides. If you like, I'll try to get a photo of the setup for you. __________________ Namaste, --Scott ><> "There seems to be no survivors to interview, but I suspect [kamakazi pilots] did not shout 'traytree' the moment before their personal sacrifice." -Herb Gustafson