Miniature roses, begonias, a birdbath, and ground cover made this charming little formal garden.
The distance between the tubes and your plants also affects intensity. The closer they are, the stronger the light. If possible, hang your fixtures on chains so that they can be raised or lowered. Adjust them to accommodate the taller plants and then raise your “little fellers” on upended pots, bricks, or boards so they will not be cheated of their share of light. Please remember, the greater the distance between light and plant, the more tubes you will need. Distance determines the number of tubes!
For greater intensity, and efficiency, forty-watt tubes (four feet long), or even larger, are usually recommended. If these are to be hung from the top of a case or cabinet, the simple strip fixtures are sufficient. If there is to be no “ceiling” directly above the lights, or if it is a decorative arrangement where glare might hurt the eyes of those who see it, use the industrial fixtures with shield-like reflectors. (In planning your light-garden, please don’t forget that the fixtures are a few inches longer than the actual tubes.)
If the case which you may be planning can be enclosed, at least on three sides, it will be easier to maintain the needed humidity. If the enclosing sides are opaque, they—and the “ceiling” above the lights—should be treated so the light rays are bounced back and the plants receive the extra benefit. In our cabinets we usually applied several coats of flat white paint on the inner surfaces. But once, under the blandishments of the aluminum industry, I lined a cabinet with their foil. It was plain foil, not the crinkled sort, so I did my own crinkling. Then I smoothed it out and fastened it in place with a staple gun. Plain foil, like high-gloss white enamel, seems to reflect the light every place except where it should be, on the plants.
In one of the installations we had at our place on Long Island I found it impossible to put in enough fluorescent tubes for the plants we wished to grow. Since they were day-neutral varieties, we made up for the lack of intensity by increasing the length of time the lights were used. Up to a point, increasing the light-hours will help to compensate for the lack of intensity—just to a point, however, and then the old law of diminishing returns takes over. Plants must not be under light so long that they fail to get their necessary periods of darkness. It is as essential as sleep is to a human being—perhaps more so.
OPERATION
In planning a light installation try to squeeze out a few extra dollars for an automatic timer. It will help to guarantee success for the operation. You’ll have a certain peace of mind if you tend to be absent-minded. No more will you fret through a P.T.A. meeting, a movie, or a concert wondering if you turned off the lights on your plants. The timer will have done it for you. If you happen to have an enclosed case—one tight enough to conserve the humidity—you can very easily go away on a short trip (a day or two at most) and feel confident your pets will not suffer. If you have postponed buying a timer—actually, they are not expensive—and have to leave your plants for a day or so, it is better to turn off the lights completely. They’ll suffer less than if the lights are going full blast. But for peace of mind, particularly that of the plants, we’ve always used automatic timers. At one time we had three of them. When I was ordering one from a mail-order company, my husband was buying me one as a birthday gift. And at the very same time the electrical contractor who redid out light system donated one in the interests of our begonias. We had them popping on and off at all hours of the day and night. We even hooked a percolator into one for the morning coffee.
As I look back over our experiments of a few years ago, I find there are more plants which are day-neutral (night-neutral if you prefer) than plants which are short-night or long-night. For these day-neutrals, fourteen to sixteen hours of fluorescent light (of sufficient intensity) every day, all year round, will keep them happy and thriving. They won’t know the difference between winter and summer, spring and autumn, Florida or Long Island. That has been our experience, but now I find opinions vary on whether hours of light should be lengthened or shortened in spring and autumn for these seasonal changes. (There is still plenty of room for experimentation. For instance, the light requirements for many plants are still to be worked out—even for closely related plants within various types.)
Some growers, those who specialize in plants for which they know the light requirements, turn on the lights at dawn and turn them off at nightfall. This is a year-around schedule. Others who have plants of assorted types, or of undetermined light requirements, maintain a constant fourteen-hour growing day. And they are often surprised by even second, or third, bursts of bloom. A nice surprise, if you ask me.