Grow Light Bulb Tutorial

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There are several types of grow lights that indoor gardeners use - These plant lights include:

Metal Halide (MH)
High Pressure Sodium (HPS)
Compact Fluorescents (CFL)
Fluorescent Tubes

Here's a brief description of these artificial plant light sources:

Metal Halide Bulbs (aka: MH)

Many gardeners recommend metal halide grow lights above all others. The reason being it's excellent spectral distribution. Metal halide bulbs emulate bright summer sunlight and contain all the energy peaks at wavelengths of the visible spectrum. To plants this means quality simulated sunlight and photosynthesis at a level much higher than that which fluorescent lamps can achieve.

Use MH bulbs during the green vegetative stage of your plants' growth cycle.

The spectral output of HID bulbs varies drastically. Metal Halide bulbs come in all spectrums, from specialized MH bulbs that are made specifically for early vegetative growth, to equally specialized bulbs that target the heart of your plants flowering cycle. The higher the "K" (kelvin units) number listed with the bulb, the 'cooler' the bulb spectrum is. Cool spectrum bulbs (6.4k-10k) are best used for different parts of vegetative growth, while warm bulbs (2700-3000k) are better for fruiting/flowering.

To keep it simple, start with bulbs that are in the range of 6400k (this applies to both T5's and HID lights), and finish with a bulb that's near 2700-3000k. (If you want to fully "explore" the science of indoor gardening, we've got customers that change their bulbs as many as 4 or 5 times during one growth cycle, but this is not necessary for good results.) Our best selling vegetative bulbs are Sunmaster Cool Deluxe, Hortilux Blue, Digillux MH, and our standard MH bulbs.

In addition, metal halide grow lights have good lumen maintenance and long life expectancy. Having good lumen maintenance means that as a lamp ages, its decline in lumen output is very gradual. After 12 months of use at 18 hours per day, a 1000 watt metal halide lamp should be replaced as it is only about 85% as bright as the day you bought it. Halide is the best bulb technology available for achieving the highest level of plant and flower growth. They allow the flexibility of multi-crop, multi-season indoor gardening.

High Pressure Sodium Bulbs (aka: HPS)

High pressure sodium plant lights are the only growlights comparable to metal halide bulbs. They have good spectral distribution, but sodium lights cannot compare to halide in the blue end of the spectrum.

Use HPS bulbs during (or to initiate) the budding, flowering and fruiting stages of your garden.

Sodium grow lights are particularly high in the yellow and red regions of the spectrum. This is the type of light fruiting and flowering plants like best. Because of the focus on red light, some varieties of plants grown with sodium lights alone can become elongated and leggy.

Sodium grow lights do, on the other hand, stimulate flower and fruit production more efficiently than metal halide bulbs, making them an important light source best used in conjunction with metal halide either in addition to, or cycled together. High Pressure Sodium bulbs also have a much longer life expectancy than metal halides, lasting up to two (2) years!

Our best selling HPS (flowering) bulbs are: Hortilux Super HPS, Sunmaster Super HPS, Agrosun Red, and Digilux HPS bulbs.

Conversion Bulbs

If you have one of these types of grow light systems, but need to move into the other type, you don't have to buy a whole new lighting system!!! We've got conversion grow light bulbs to accommodate your every need!

HID Conversion bulbs make it possible to run a halide bulb from your sodium ballast or a sodium bulb from your halide ballast. So you could run a halide to bring your plants through the vegetative stage then switch to a sodium conversion bulb to finish 'em off through flowering.

Dual-Spectrum bulbs

The newest addition to the HID bulb category is the "Dual-Spectrum" bulbs.

These are very intricately designed bulbs that contain the inner workings of both MH, and HPS bulbs, both artistically installed into the same glass outer housing of a single bulb.

This is a growing category, and we'll be adding more dual-spectrum options over time. When you light one of these bulbs, it's a thing of true beauty. Even with all of the advancement in bulb spectral output technology, this is still the clearest example of a true full-spectrum bulb. Dual-spectrum bulbs can be used in all stages of growth, and will give you excellent results every time. Plants love these bulbs, and grow and develop very nicely as a result.

LED Grow Lights

We've found that plants respond to LED lights similar to T5 fluorescent fixtures. They result in tight inter-nodal growth, and short stocky, strong plants. The plants do look a little different - the leafs tend to curl down. But the leaves are thicker and a more healthy shade of green.

Vegetative growth is a little slower compared to a 400 watt HPS light but are healthy and progress normally. Fruiting and flowering is also slightly slower but healthy and strong, with surprisingly dense development. The fruit and flowers are more realistic in color and are beautiful.

Fluorescent Tubes

Fluorescent bulbs have come a long way! The old T12's are being phased out of the marketplace, and replaced with T8, and T5 bulbs and fixtures.

T5's are the best quality fluorescent lights for horticultural purposes, and work great for everything from cloning or seedling germinating, to the early vegetative stages of growth for larger plants. T5's excel at vegetative growth up to about 12" tall.

For leafy green and herb gardens, they simply can't be beat. They also work great for bonsai trees, houseplants, and orchids.

The light quality from T5 lights is gentle, and doesn't produce much heat so they can be used in small areas. The best bulbs for vegetative growth are the 6500k bulbs, and for orchids, or other short flowering plants, the 2700k bulbs work best. You can also mix the bulbs to produce a full-spectrum light.

T5 fluorescents put out 5000 lumens per tube and have solid state electronic ballasts that do not emit heat, noise or vibration.

Compact Fluorescents

Compact Fluorescents are a proven success as horticultural lighting. In their first year on the market, they have proven themselves as a perfect grow light for seedlings, cuttings and small plants.

Compact Fluorescent bulbs are ideal for small spaces as they do not produce much heat or use much electricity. For fruiting or flowering plants, the 2700K warm bulb is superb. For plants taller than a foot, regular fluorescent tubes can be supplemented on the plant sides.

OK, now that we've got an idea about the kind of grow light bulbs we want, let's take a look at the grow light systems.

Or, if you just need replacement growlight bulbs, go right to our bulb page!

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