LED grow light developers have hit the indoor horticultural scene with a storm of new and innovative products. They offer growers new benefits that they have not had access to before. They are small, highly efficient, emit perfectly customizable spectrums, last over 20 years, and emit virtually no heat.
LED lights are incredibly customizable, and come in a variety of colors, sizes, and light intensity. Some are designed to offer only one spectrum, intended for specialized use during one plant life stage, while others can be changed and customized to offer different light spectrums during different life stages of plant development.
What is an LED Light?
LED stands for “light emitting diode”. This refers to a small electrical diode that converts electrical energy into light energy. They are very small, and extremely efficient. When combined in an array of a few hundred, or a few thousand, these small diodes can emit an impressive amount of light, with very little electrical energy.
What's so special about LED lights?
LEDs are special because they offer this customization that HID and CFL lights simply can’t, and they are also incredibly efficient with how the energy is converted from electricity into light. LEDs currently convert around 1 watt of electricity into 100 lumens. Compare this to the CFLs which convert 1 watt into around 50-70 lumens, or HIDs which result in only 30-80 lumens per watt depending on temperature, and individual bulbs/ballasts.
LEDs are so efficient, that nearly no heat is released from their housings. An LED can be used in a small grow room or tent with little or no ventilation or cooling needed. In any grow environment, it is beneficial to have an extraction fal pulling new air into the room, and removing old stale air. With LEDs however, the rate at which these fans run can be reduced as they will not need to work nearly as hard in order to keep the room coo when compared to HID lamps.
The other thing that makes LEDs so incredible are their extremely long working life. A good quality LED grow light, loses only about 20% of its efficiency over the course of 20 years! That far outlives HID lamps and even the long lived CFL lighting.
Photomorphogenesis: The Science of how plants use light
Photomorphogenesis is the study of how a plant's growth pattern responds to different light spectrums. Nearly all plants have specialized proteins contained within the leaves of the plant that pick up and measure the light spectrum that it sees. It uses this information to decide how it's going to grow, and what to spend its stored energy on.
This can vary greatly in different plant species but generally results as follows:
1. Red light spectrum
Light spectrums containing mainly red light will cause most plants to begin spending its energy on the development of flowers, fruits, and stem growth. This causes the root growth to slow down, and tells leaf production to slow or halt altogether.
Blue spectrums usually cause plants to focus more on root and new leaf production, and tends to halt or slow the production of flowers and fruits. It also helps to keep the plants stems shorter which keeps them from growing too tall and thin and flopping over.
Green light is not generally seen by plants, and is reflected off the leaf surface as a result. This is why plants appear green to our eyes. The other colors in the light spectrum are absorbed by the plants, leaving only the green behind to bound off and reach our eyes.
How this information is applied
Keeping photomorphogenesis in mind, we can now combine this information with the technology of LED lights. Since these lights are so efficient, and so customizable in what color they emit, we can optimize this for the spectrum of lights our plants prefer. This means that if a redder spectrum is preferred by our plants in their current life stage, we can provide a larger amount of that particular spectrum for our plants to soak up and use as energy. By doing this we waste less energy by producing the light that are plants are not going to use anyway.
LEDs can also be customized to emit nearly any spectrum of light. The higher ratings, around the 6000K range is viewed as a blue heavy light. For the vegetative phase of growth, this spectrum is perfect for telling the plant to spend its energy on new leaves, and roots instead of the energy thirsty flowers and fruits. LEDs can be optimised in this range to deliver the best spectrum possible for any given species of plant.
What is the future of LED lighting?
LED is a fast evolving field of research. The current efficiency is about 100 lumens per watt for most LEDs. This has grown substantially in recent years, and is projected to reach the 150 lumens per watt range by 2020. As more companies like Philips lighting spend money on researching the best spectrums to use for different species and life stages of plants, the field of LED lighting is likely going to dominate the growing scene. The incredible energy efficiency and long working life makes them an attractive option for growers looking for long term savings.
This ever developing technology will likely become the standard of the indoor growing industry, and is becoming more affordable and energy efficient than ever before.
Even today, more and more large scale, and hobby grows alike are choosing to go with LEDs for their incredible benefits and long-term cost effectiveness as a source of light.