LED GROWING LIGHTS

  LED ECONOMICS

After decades of research and development the industry has emerged to address one of the planets most critical concerns: ENERGY.  Advances in lighting technology are allowing growers to reap the rewards of higher yields but with a significantly smaller footprint both in terms of immediate and long term energy savings.  Where HID lighting showed us that indoor gardening was possible the LED revolution advanced the industry to a higher leverl of efficiency and economy.

Although the initial investment of LED grow lights may still be higher than HID lighting, the long term benefits of currently produced LED lights far outweigh their initial costs.  One way to compare HID lights with LED  lights is the energy test.  If you are given 1000 watts of electricity, what can you produce with that 1000 watts using traditional HID lighting compared to modern high output LED grow lights?  (example: one 1000w MH grow light vs three 300w LED grow lights)  Current findings show that on a watt per wass basis a state of the are LED light can outperform HID by a full 2-3 increase in raw biomass.

USING LED GROW LIGHTS   

SEEDLINGS AND CLONES  LED grow lights should be placed anywhere from two to three feet above the growing tops of seedlings and clones.  This insures that the new starts will not be over stimulated by the intensity of the lights.  Once the plants produce a network of branches the lights may then be lowered to anywhere from eighteen to twenty four inches for the extensive vegetative period of growth.  Do not move LED grow lights any closer than twelve inches from the growing canopy as this will most likely burn the sensitive new growth due to the amount of  radiant heat produced by the diodes.  This problem could be accentuated if the ambient temperature of the grow room is relatively high. Also, when an LED is placed too close to the canopy the effective lighting footprint  is reduced leaving adjacent plants without adequate light to thrive.  Note that LED lights that are  placed too close to a plant will result in a diminishing returns effect whereby as the light moves closer it has an ever decreasing effect on growth.  Maintain the twelve inch rule.

TEMPERATURE The ideal temperature for plants being grown under LED grow lights is between seventy five and eighty five degrees.   If supplemental CO2 is being added then the upper limit of this estimate or slightly beyond the upper limit  is preferable.   Generally as the grow room temperature rises the ability of the plant to utilize CO2 increases up to as high as ninety degrees.

CO2 As with HID CO2 can increase plant growth dramatically.  Ambient  levels of CO2 stand at about 400ppm.   A growroom at seventy five degrees can make use of CO2 up to 1000ppm.  From this point temperature may be increase up to ninety degree with a corresponding increase in CO2 peaking at 1500ppm.  After this the plant will reach CO2 saturation and any increase  will be wasted.  Note that when operating CO2 at these elevated levels it is recommended that  extended periods of time in the grow room  be avoided.

HUMIDITY The use of LED growing lights will tend to result in grow  rooms that are cooler than grow rooms equipped with HID lighting.  This difference in temperature can also have an effect on humidity levels which in turn have an effect on the growing rate of plants along with other considerations.  A conscious effort will be needed to maintain growroom temperatures along with an awareness of the resulting humidy levels. When humidity levels  are low, nearing 50 percent the result will be that the plant will produce narrow leaves which will prevent water in the leaves from evaporating at an acceptable level  This limitation will cause a slowing of growth.   As the humidity levels reach upward to sixty five to seventy five percent an optimum rate of growth can be maintained whereby the leave surface will increase and transpiration can effectively take place.  As the humidty levels are further raised again the plants rate of growth will decrease since now the plant leaf surface will find it difficult expelling water into an environment that is already saturated with humidity.  Another consideration for avoiding high levels of Humidity will be that  various molds and pathogens will find the environment more to their liking potentially resulting in disease. 

WATERING  Making the transition from HID to LED often times require that  old habits need to be modified.  The two most difficult areas of adjustment are water and fertilizer requirements.  Since LED growing lights produce less radiant heat the rate at which water is released from the plants leaves is reduced.  This accordingly will necessitate that the grower  become more sensitive to the overwatering potential especially in soil cultures.  There is often an erroneous tendancy  to maintain the same schedule that was established while growing under HID lighting. 

FERTILIZER Somewhat parallel to the watering issue is the fertilizer schedule.   By using LED lighting in the garden the grower may experience an increase, a decrease, or no change in growth rate.  So many factors will interact to determine the outcome.  The most important thing to understand is that this is a time when the grower can no longer rely on previously established patterns that were based on a light source  no longer being used.  How much fertilizer to use is purely a function of the plants ability to absorb nutrients and this can change dramatically.   A new fertilization schedule will need to be established based on the current environmental conditions in the grow room along with observable signs given by the plants such as their overall growth rates, the curling of leaves or the burning of leaf tips.