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Journal American Rhododendron Society

Current Editor:
Dr. Glen Jamieson ars.editor@gmail.com


Volume 24, Number 4
October 1970

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Natural Outdoor Light - Indoors?
Eldred E. Green, Chicago, Ill.

        Growing plants under controlled conditions has long been a goal of plant growers everywhere. While great steps have been made in controlling humidity, heat, and even watering, the problem of adequate light has remained.
        Artificial light has had drawbacks in excessive heat from incandescent bulbs, unbalanced wave lengths from fluorescent tubes, damage from some types of lights, and cost of electricity, fixtures, and tubes or bulbs. Various ways have been used to overcome the deficiencies of artificial light such as combining fluorescent and incandescent lamps in various ratios. using a warm white and daylight type of fluorescent tubes as pairs in fixtures, using daylight and supplementing it with artificial light during dark weather or the short days of winter.
        One of the persons faced with artificial light problems was John Ott. Mr. Ott had developed a hobby of photography into a commercial business of time-lapse photography. This is the taking of pictures in a controlled time sequence so that a flower will burst into bloom within seconds on the screen or an apple will go from flower to ripe fruit in a few minutes. This type of photography relies on controlled conditions; adequate light for making the photograph at the proper time, a set-up of the camera that does not change position, and many other problems. Controlling conditions for the cameras was solved. However, when plants were grown under fluorescent tubes other problems arose. Some color tubes induced leaf growth, others produced staminate flowers, a different type produced pistillate flowers, some did not cause normal colors to develop in fruit.
        Mr. Ott tried all the various sources of artificial light that he possibly could but each had some drawback and was not totally satisfactory. A few years ago he learned of a fluorescent tube that had been developed by a industrial lighting manufacturer for use in color matching fabric dyes and printing ink in industrial applications.
        The tube was being sold under the trade name of Optima by the Duro-Test Co. of New Jersey. The company sells primarily through salesmen and architects and similar outlets. However, the company does have stores throughout the country where small numbers of bulbs of all types can be purchased.
        Mr. Ott got in touch with the Duro-Test Co. and tried the Optima tubes. The Optima tube is made so that a balance of wave lengths of lights is given off that approximates those of natural sunlight within 10%. Mr. Ott suggested that an addition of a slight amount of ultra-violet rays be added to make the tube even closer to natural light as Mr. Ott had discovered that some of the effects of growing plants under glass could be controlled by using glass that passed ultra-violet rays. The Duro-Test engineers experimented and came up with such a tube. They named it Vita-Lite. It has a spectrum that is 92% that of natural daylight. Mr. Ott immediately started using the tube and has unqualifiedly endorsed it as being far superior to any source of light that he has used.
        My own work with artificial light has been on a small scale mainly in growing seedlings for outside use during the dark weather of late winter. I had tried some of the so-called plant growth tubes with no apparent benefit and even some positively harmful effects. When I learned of Vita-Lite I immediately obtained tubes for my own use. The results have been good. Two of the objections to the plant growth tubes are overcome. There have been no harmful effects even with plants touching the tubes. The light does not produce eye strain or distort the colors. Plant growth has been excellent. This seems to be the replacement for daylight that we have been hoping for. Now completely controlled conditions can be created.
        Vita-Lite tubes can only be obtained from Duro-Test. The initial cost is about twice that of the regular standard fluorescent tubes but the guaranteed life of the tubes, 20,000 hours at 90% output, far exceeds that of any others. The tubes come in standard sizes and fit regular fixtures.
        Vita-Lite is obtainable from Duro-Test Corporation, North Bergen, N.J. There are sales offices in Chicago, Atlanta, Omaha, Dallas, and San Francisco and exhibit rooms in New York, 6 E 53 St., and in Chicago at 324 N. Michigan Ave. In these centers comparisons can be made with the standard fluorescent tubes.
        While my own experience with VitaLite tubes has not been aimed at comparing them with other kinds of tubes but with ascertaining their value in growing plants, I have found that Vita-Lites are much easier to work under. There is no unusual color distortion that is found with all other kinds of artificial light. There is no injury even if plants touched the tubes such as occurred with some of the advertised plant growth tubes. Growth maintains a natural color and size and is healthy in all ways. It just occurred to me that I have had no damping off in several thousand seedlings of various kinds which I have started this year under Vita-Liter. Whether this is coincidence or not I cannot say as I did not run any checks but I have always had some little trouble along this line in previous years using the same methods. It's conspicuous that I haven't had any since using Vita-Lite.
        Rhododendron growers may do well to investigate the possibilities of this source of light for growing seedlings, lighting cuttings, and in other applications where artificial light may be preferable to sun.
        There are a number of other side effects that have been found with experiments using Vita-Lites. Mr. Ott has found increased longevity and better growth in animals, better health in people working under them, better spirits or mental attitudes, and indications of control of certain diseases. As yet much of this is still in the experimental stage as Vita-Liter did not become available until late in 1967.
        Mr. Ott has told me that he is using Vita-Lite exclusively for his time lapse work. He is enthusiastic about the results he has obtained with them. For myself, I am going to replace my present fluorescents with Vita-Lite as soon as they need replacing. At the present I am using the standard tubes to handle the overflow from the VitaLite areas. And the plants are rotated so that they do receive light from various types of tubes.
        Incidentally, color film of the outdoor type can be used under Vita-Liter with no filters. Film balanced for daylight reacts the same under Vita-Lite.
        While I have known Mr. Ott for many years I was unaware of his interest and connection with Duro-Test when I tried using Vita-Lite. Actually the connection was discovered when I attended a meeting where he was the speaker. I was "sold" on Vita-Liter before talking with Mr. Ott. That was just additional confirmation.


Volume 24, Number 4
October 1970

DLA Ejournal Home | QBARS Home | Table of Contents for this issue | Search JARS and other ejournals