Let There Be Light – the Right Light

For Robust Plant Growth and High Yields: Let There Be Light – the Right Light

If you want healthy, robust plants that give you the best yields, you need the right humidity, temperature, and light. Too much or too little can mean plant stress – and lower yields. In this last article in this series, we’ll talk about light.

Plants need light – but not just any light

There’s a lot to consider when you need to buy grow room lights. First is type:

• High Intensity Discharge (HID) lights

High-Pressure Sodium and Metal Halide lamps used to be most common of the HID lamps used; Metal Halide lamps produced “blue spectrum” light to promote plant growth, and High-Pressure Sodium lamps’ orange-red glow increased flowering in plants.

These have become less common in recent years in favor of first, Compact Fluorescent lights (CFLs) and now, Light Emitting Diodes (LEDs).

• Compact Fluorescent lights

Newer 6400 K (blue) and 2700 K (red) took the place of the HIDs because they were safer to use and cost less. You’d need both blue and red lights for your grow room: blue for the growth phase, and then a gradual switch to more red when plants move into the flowering phase.

• LED (Light Emitting Diode) lights: Your best option?

Until a couple of years ago, CFLs beat out LEDs, but today, LEDs are favorites in the grow room market. They have advantages over CFLs, because:

They cost much less to operate

1. Your energy bill could drop as much as 80% versus HID lights.

2. LED lifespans are much higher, up to 50,000 hours, as opposed to an average of about 8,000-10,000 for the average CFL; that means less frequent replacement.

They don’t emit much heat

HIDs especially have heat concerns, but LEDs don’t. This has several advantages:

1. No unavoidable temperature fluctuations

It’s easier to control the temperature of your grow room.

2. Your thermal footprint is much smaller

…and therefore much less intrusive.

3. LED fixtures can be constructed to cover the full spectrum

CFLs require you to switch from blue to red light at the appropriate stage of growth. By contrast, red/blue LED combination fixtures are available, so that there will be no need to switch colors from one stage of growth to the next.