The vegetative light cycle of cannabis is when plant growth truly takes off. Much like a human adolescent, the plant will achieve most of its vertical growth during this time. Lasting between 3 to 16 weeks, the vegetative stage requires full-spectrum light for 18 hours and 6 hours of darkness.
' plants do require a daily respiration period of at least 6 hours per day (for seedlings) and ideally 8-10 hours for more mature plants. Therefore we do not recommend providing more than 14-16 hours per day of light, even if you are growing long-day-loving varieties and trying to induce flowering/fruit from them.
A: In general, you should not leave grow lights on 24/7. Plants need a light-dark cycle to develop properly. It's believed that they truly do “rest” during periods of darkness, and probably use this time to move nutrients into their extremities while taking a break from growing.
Height of plant: Depending on the strain, plants will generally double in size during flowering. So, if 'room' height is limited, the switch to 12/12 will need to be done no later than when the plant has reached 50% of the 'available' height (remember to consider the minimum gap distance between lamp and foliage).
If the light is too close to your plant, it may get too hot and can damage your plant. If your plant's leaves start to turn yellow or brown, or are starting to curl up, your light may be too close to your plant any may be burning your plant!
In the vegetative stage, LED grow lights should be between 12-24 inches away from the top of the canopy. During this stage, more light is needed for photosynthesis, so the light source should be located closer to the plants. As the plants progress through the flowering stage, their demand for intense light decreases.
While some plants need less darkness time than others, too much light will impede any growth schedule over time. Too much light can also refer to the intensity of the light. Intense, direct light is great for some plants, but it will damage (or even kill others).
Cannabis in the vegetative stage (when it is growing at a rapid pace) needs at least 13 hours of light per day. In fact, indoor growers commonly use an 18/6 light to dark ratio to encourage faster growth.
Increased light duration allows the plant to make sufficient food to survive and grow. However, plants require some period of darkness to properly develop and should be exposed to light for no more than 16 hours per day. Excessive light is as harmful as too little..
Even though plants are in their bloom stage and thrive off the "RED" light emitted by the Bloom mode they still require some blue and green light to really thrive. Always have both switches ON (VEG and BLOOM) once you plants are in the Blooming stage.
To be effective, grow lights really need to be on for at least 8-10 hours a day. This can vary up to 16 hours, depending on the conditions. That's why LED grow lights are so popular – when they have to be left on all day, it's best to use an energy efficient type! Always position a grow light above the plant.
Seedling Daily Light Needs
Leave the grow lights on for 14 to 16 hours per day to provide light for the young seedlings. It's best to turn the light on early in the morning and turn it off around dusk. Your seedlings will still thrive if you deviate from this schedule.
Plants, shrubs and trees use sunlight for photosynthesis during the daytime, but at night they need darkness to regenerate a key compound - phytochrome. Nighttime lighting can reduce vegetation's ability to properly create this compound.
LED grow lights typically last for 50,000 hours or more, whereas HID bulbs generally last 10,000 to 18,000 hours, depending on the specific type of bulb. When it comes to longevity, there's really no competition. A major advantage of using LED grow lights is the huge spectrum of energy they provide.
Cannabis plants are happiest when they get between 10–12 hours of direct sunlight per day. As you'll likely have witnessed with your own eyes, weed plants grow really vigorously, and hence need a ton of solar energy to fuel their growth.
The main reason why green light is purportedly not useful to plants is because it is poorly absorbed by chlorophyll. However, absorption of chlorophyll is usually measured using extracted and purified chlorophyll, in a test tube (in vitro), and not using an intact leaf (in vivo).
Although different species have varying light requirements, no plant can tolerate continuous light exposure for 24 hours a day. Like nature's cycle of light and dark, plants need a daily period of darkness and rest to remain healthy.
Vegetative
Lasting between 3 to 16 weeks, the vegetative stage requires full-spectrum light for 18 hours and 6 hours of darkness. Some argue for 24-hour light cycles during this stage, but that choice may lead to nutritional deficiencies and stunted growth in the final flowering stage.
You can remove fan leaves during flowering in much the same way you do during veg. Prune away large leaves that are overshadowing bud sites, as well as dead or dying fan leaves. One thing to keep in mind is that you should prune in intervals, giving at least a couple weeks between each session.
The last three weeks is when your buds can actually gain the most weight – that is if you feed them Overdrive®. After your peak bloom phase, your plants enter their late bloom phase (the precise timing and length of which depends on the strain of cannabis you're growing).
At a high enough intensity, any type of light, regardless of the source has the potential to harm the eyes or skin through prolonged thermal exposure or photochemical effects of ultraviolet, blue light &/or infrared emissions.
One common LED myth is that these grow lights contain dangerous heavy metals such as mercury. While this is incorrect, it is a myth based on a former truth. With the advancement of LED technology, neither of these things are true today. Nowadays, diodes emit light directly and they don't contain mercury.
UVA and UVB radiations are present in the sunlight and the light produced by LED grow fixtures. These two types of radiation are dangerous to humans. They can also cause various skin diseases, including skin cancer.
If you're planning on growing veggies, a full spectrum light with a color temperature in the blue range (5,000 – 7,000K) is recommended, and for fruits and flowers, the red range (3,500 – 4,500K) is the guiding light.
600W – Between 18 and 30 Inches.