By Scott Misener

That great big fiery orb in the sky is the reason there is life on this planet. Plants need light to turn nutrients into energy. The leaves of the plant act as solar panels, harnessing the sun's energy and storing it to withstand the rigors of the vegetative and fruiting/flowering cycles.

If you were lucky enough to own an atrium or a greenhouse, you would be foolish not to take advantage of the natural light that is at your disposal. No light system available on the market today can come close to the intensity and spectrum that natural sunlight provides. Not to mention that it's a lot cheaper. Depending on what kinds of plants you are growing, you may want to consider some kind of light system for supplemental light. Tomatoes and bell peppers, for example, need a certain number of sunny days to fulfill their developmental needs, a number we don't get up here under the fog belt. Plants will vegetate, or grow in size and structure, as long as it is exposed to at least sixteen hours a day. A plant will fruit and flower when it is restricted to twelve hours or less. These are Mother Nature's rules. Indoor lighting tricks Mother Nature and forces plants to follow your schedule.

There are two commonly used bulbs, or lamps, used in indoor gardening - Metal Halide (MH) and High Pressure Sodium (HPS). MH provides a blue spectrum simulating the spring and early summer spectrum, which plants naturally use during the vegetative phase of their growth cycle. High Pressure Sodium provides the red side of the spectrum, which imitates the sun's spectrum in late summer and autumn. That wild and crazy red spectrum plants crave throughout the fruiting/flowing phase. If you purchase a switchable ballast, "switchable" meaning a ballast that will fire both MH and HPS bulbs, you will have a growth advantage because you are providing the plants with the specific spectrum they need. There is a catch. It will cost you $100 more for this luxury. If you're going to use one type of bulb only, make it a HPS. HPS delivers more intensity than MH, and intensity makes all the difference during fruiting/flowering. Hortilux and Grolux are examples of superior bulbs enhanced with extra blue light not found in those standard, cheaper HPS bulbs. The lamp is the delivering component of your system, so it pays to spend the extra $30 to upgrade. If you want to see the color difference in the light output of these two bulbs, look out your window. MH and HPS fixtures have been used for years in lighting fixtures and street lamps. They just so happen to have a spectrum that plants can use.

Incandescent bulbs have a very small amount of spectrum that plants can use and usually require a wattage of 150 watts or higher to have any beneficial effect on plants. That means you have a very hot bulb in a regular light fixture. Be careful!

Fluorescent lighting provides an excellent alternative for indoor gardeners on a budget. These lights provide a cost effective, cooler burning light system. Newer fluorescent fixtures like the Tek-light T5 fixture offers a spectrum made specifically for plants. Just make sure to drop those fluorescent fixtures down on those plants. Fluorescent lights are nowhere near the intensity of MH or HPS lighting systems, and the light intensity dramatically diminishes the further away the lamp is from the plants. For example, one foot away from the lamp is 100% of the lamps intensity. Move another foot away and the intensity becomes 22%. Make the most out of your light! You're paying for it.

In gardening, like in all other aspects of life, you're only as strong as your weakest link. You can pack your atrium or greenhouse with as many high-tech lighting systems as your budget will handle, but without the proper ventilation and air exchange, you will have dismal results. Light systems create heat. Plants will stress and stretch when temperatures climb past ninety. Pests love hot dead air. Only a couple of things you will face if you brush off your ventilation. Air is everything. . We'll finish this next week.

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