Grow lights are a great tool for making the growing process more efficient, but they can also be harmful to the plant if not used correctly. Here are 10 things you should avoid doing when using LED and other types of grow lights.
Using the Wrong Light Schedule
You should be careful not to leave the lights on all the time, or worse, the opposite – forget to turn them on. It might sound trivial but it’s quite easy to mess up the light schedule and even a minor change might have a negative impact the plant’s growth. Cannabis needs about 18-24 hours of light during the vegetative stage and 12 hours of light during the flowering stage.
Using Inferior Products
Light is among the most vital factors to consider when growing plants because it triggers the photosynthesis process. If you’re using regular incandescent lights, you’re not very likely to grow strong and healthy plants. Therefore, for best results it is recommended that you use full spectrum LED grow lights. They are specifically designed for the purpose and have the feature to deliver light in the exact spectrum the plant needs.
Compare a bulky HPS light with a parabolic reflector to a small sophisticated LED. The HPS is hot and heavy. An LED runs cooler, is often small and slim and won’t take up all the space in your tent. People with small grow tents often find LED is the best/only way to produce cannabis.
A 600W HPS bulb wastes around 450W (75%) of the electrical energy producing heat. A good quality LED light with a 400W power draw would produce around 200W of heat despite having the same productivity as a 600W HPS. So the best LED’s only produce about half the heat of an HPS.
For some growers that will allow a significant simplification of the grow room, such as no air conditioning in hot climates. Other growers will be able to turn down air extraction rates or use smaller extraction fans.
You may not notice this issue since soil (and many grow nutrients) already contain adequate levels of Calcium and Magnesium. Calcium/Magnesium supplemental nutrients are widely available in any grow shop.
Growing cannabis with LED is becoming a mainstream alternative to HPS. Although the initial purchase cost of an LED is still higher than an HPS, the ongoing running costs are lower. LED produces less heat than HPS and this affects many aspects of plant maintenance and grow room design.
Traditionally many cannabis growers fight grow room temperatures, their grow rooms usually running 3 or 4ºC above the optimum point. With LED grow rooms run naturally at a cooler optimum temperature.
The best LED growers have found that the lower levels of grow room heat and the cooler tent conditions with LED is allowing more of the delicate terpenes and flavonoids to remain in the plants tissues rather than being lost to the atmosphere in a hot HPS tent.
Growroom heat levels are totally different with LED
When light levels are too intense the tips of the plants are bleached, they look white instead of green. This can be a sign to raise the LED lights higher, or to tie down the tallest branches of your plants.
LED lights usually produce much less heat than a HPS light of comparable productivity. The lower heat levels from a LED means the leaves of a cannabis plant generally transpire (evaporate) less moisture under LED compared to HPS.