I Have Heard that LEDs are Great for the Vegetative Phase but can they be used for Flowering?
The simple answer is YES, if you have a high enough light intensity.
The key to a healthy bloom and good yield is having the right level of PAR (photosynthetically active radiation) light for the type of plant you are growing. The standard way to measure PAR light is in micro-moles per square meter per second (µmoles/m2/s). On a sunny day at noon in California, the sun delivers around 2,000 µmoles/m2/s. Different plants require different levels of light for healthy flowering. For example, lettuce and potatoes can grow under only a few hundred µmoles/m2/s. Red peppers require higher levels and tomatoes need light levels 1,000 µmoles/m2/s or higher. Too much light does not necessarily help: Plants only absorb a certain maximum level of light and the rest is reflected back. This maximum level is called the "light saturation point" and it varies from plant to plant. In order to achieve good flowering, the leaves of your plants need to receive PAR light levels that approach their light saturation point.
Well designed LEDs lights concentrate their emmited light in the deep blue and deep red part of the light spectrum where absorption by plants is highest. Thus, LEDs allow you to achieve good bloom with a lower PAR light value compared to HID lights. If the LEDs are delivering light in the right parts of the spectrum (deep blue 430-460nm and deep red 650-670nm) where absoption is at its maximum, the PAR value required for bloom can be 40-50% below that of HID type lights.
Many Chinese made LED grow lights use low power one or two watt LEDs with common colors used for traffic lights, etc. not well suited for horticulture. Companies importing and marketing these lights make all kinds of claims about results and show pictures of various plants growing as proof. Just because you can grow lettuce under UFO type lights does not mean you will get tomatoes to bloom.
However, SolarStorm LEDs use the latest 5 Watt LEDs which are the most powerful single die LEDs on the market. The light is concentrated in the right parts of the light spectrum deep blue (430-460nm) and deep red (650-670nm) where absorption is highest. SolarStorm LEDs grow lights deliver PAR light levels that are at or above the light saturation point of the most demanding plants. This produces excellent results in flowering when the light is positioned 18" to 24" from the plant canopy.
What are the Advantages of LED Grow Lights Over Other Types of Lights?
Indoor horticulture adopted HPS and MH (HID) type lights a long time ago because they were the only systems that delivered a high enough level of PAR light. Even though HID lights were developed for outdoor street lighting applications, they delivered good results when used for indoor growing. However, HID lights suffer from a few drawbacks. First they are not the most efficient at delivering PAR light and thus lose most of their energy as heat rather than useful light for plants. This results in huge energy bills as well as the need for supplemental cooling of the lights with fans and ducting. Fluorescent lights do a good job for vegetative growth but are not powerful enough for flowering. These traditional types of grow lights cannot be designed to deliver the specific light wavelengths that plants absorb the most. LEDs are much more efficient and create much less heat to generate high intensity light for indoor growing and therefore do not require supplemental cooling. Also, LED technology makes it possible to select only the light frequencies most absorbed by the plants further reducing energy waste and improving growing results. SolarStorm lights can typically reduce energy costs by 50% or more.
Are LEDs More Expensive to use Than Other Grow Lights?
When looking for a grow light solution, you need to take a look at the full cost picture: Price of the light, price of the system and cost of electricity over time. LED grow lights are more expensive than traditional lights when first purchased. However, when you include the full cost of an HID system including cooling, ducting, wiring, installation, etc... the cost can be about the same. The big savings come when you factor in energy cost: By reducing energy usage by 50% or more, LED's deliver major dividend, often within the first year. Additionally, LEDs never require bulb changes and are rated to run for over 50,000 hours. This represents a 12 to 15 year life span in most growing situation. Traditional light bulbs are only rated at 10,000 hours and most growers change these every six months to a year. Over a 12 year period this represents a bulb cost of over $2400.00 for each 1000 watt HPS bulb! When considering the energy savings and bulb replacement costs, LEDs are much less expensive than traditional grow lights.