According to each stage of plant growth, plants need different levels of light. In order to know exactly how far a plant should grow, it is important to consider the different growth stages. It is also important to consider the power output of the LED grow light, which is usually related to the power of the light source, which is the main factor that determines the optimal distance of the LED grow light when the growth process begins.
Plant growth can be roughly divided into three parts-nursery, nutrition and flowering
Seedling stage
At the early stage of seedling, LED grow lights should be placed above the plants to avoid dry soil.
Some growers may try to use high-intensity light to explode the seedlings to promote faster growth, but it will not help until the plant is established. At this early stage, the seedlings are too fragile and require gentler methods. Once the plant matures, it needs higher light intensity to promote photosynthesis.
Vegetative period
During the vegetative phase, plants respond well to strong light-during this period the plants gradually mature and grow rapidly through photosynthesis. In order to increase the light intensity, the LED grow light should be located closer to the plant canopy. Firm, healthy stems and roots are the key to successful repeat yield.
Increasing light intensity can promote nutrient growth, but it is important to monitor plants closely to ensure that you pay attention to adverse symptoms caused by excessive or insufficient light.
Flowering
Flowering is the final stage of the plant's growth cycle-during this period fruit production and stem growth accelerate. With the transition from the vegetative stage to the flowering or flowering stage, the best method is the "stage" transition process. For this reason, gradually increase the height of the LED grow light away from the plant ceiling (use the height recommendations outlined above). Monitor the distance closely and keep in mind the height and flowering requirements of the specific plant/crop.
For seedlings, LED grow lights should usually be installed between 24-36 inches above the plant canopy, but this depends on the power (watts) of the light source. Keep the LED grow light as far away as possible (about 36 inches) from the seedlings-this will keep the heat and light intensity low and help prevent the seedlings from drying out. Once the root system is established and begins to sprout, the light can be moved closer (usually within the first 2-3 weeks).
During plant growth, the LED grow light should be 12-24 inches from the top of the canopy. At this stage, photosynthesis requires more light, so the light source should be located near the plant.
As the plant enters the flowering period, the need for strong light decreases. The leaves at the top of the canopy should be 18-24 inches from the light source to bloom. It is at this stage that the plant grows tall and bears fruit. Depending on the light and how you want your crop to grow, you don't have to change the height of the light during flowering, especially when you don't want tall plants.
How far should the LED grow light be when cloning cannabis?
Cannabis cloning is the process of using cuttings or cuttings of mature plants to grow another plant of the same species. The light distance of the LED above the clone is different from the height of the seedling. For cloning, they need strong light to start. Depending on the light intensity and maturity of the plant, the difference between 14 and 36 inches from the top of the canopy can be significant.
The adverse effects of excessive light intensity
When plants such as cannabis receive too much light at any stage, they usually show painful symptoms. Since LED grow lights do not emit too much heat, the main issue that requires close monitoring is any signs of "burn out". Other side effects associated with grow lights that are too close to the plant canopy may be discoloration or interrupted growth/irregular growth. Both must be quickly identified and the height of the grow light must be adjusted accordingly.
Cannabis plants have signs of mild burning, including upward leaves and so-called "bleaching." Bleaching is the white or yellow on the leaves closest to the light. When the plant's veins turn green and the rest turn yellow, mild burns can also be recognized.
Increase the distance of light-cannabis and other plants
As growers move crop production indoors, the use of LED grow lights to produce hemp has become more and more common. LED grow lights also benefit growers because they can use a specific spectrum to provide more targeted lighting for different crops. Compared with traditional light sources, other benefits of considering the use of LED plant growth lights include lower power consumption, lower forward heat and increased output in a shorter period of time.
The distance of the enhancement should reflect the height and uniformity expected by the grower, and spread with leaves and healthy flowers. If we look at the crop demand of salad vegetables or lettuce compared to hemp, we will find that salad vegetables and lettuce are suitable for short-term, wider growth, while hemp is more suitable for taller and narrower growth.
Pay attention to the light time
1. Determined according to the degree of light-loving of the plant
Not to mention that LED grow lights do not rest, almost all living things need to rest, so it is impossible to use LED grow lights to fill the plants with light, which will have a bad effect on the plants. Studies and experiments have proved that the best time to add light to plants is controlled at about 12 hours, and it is necessary to leave enough time for plants to rest for 4-6 hours.
For light-loving plants, it is necessary to use LED grow lights to supplement light for plants at 6:00-10:00 and 17:00-00:00, because 10:00-17:00 is the sunlight that meets their growth needs Time period, so it takes about 11 hours for the plants to fill in the light.
For plants that don't like light, they can meet their growth needs when there is sunlight. The time for supplementing light with LED grow lights only needs to be set according to the local sunrise and sunset time, and the light supplement time should avoid plant rest time as much as possible.
2. Set according to the planting environment
The planting environment mentioned here includes the difference between the north and the south, the difference between spring, summer, autumn and winter, and the difference between indoor and outdoor sunlight. Regional and seasonal differences can be set according to the light law, the closer to the equator, the stronger it is to set the lighting time with LED plant lights. Strong in summer and weak in winter, set the lighting time with LED grow lights according to local conditions. There is a big difference in the light that indoor and outdoor plants can accept. It takes 16-18 hours to fill up the light with LED grow lights in the room, and the LED grow lights for outdoor plants are based on the difference in the illuminance of sunlight.
LED grow lights will generate a certain amount of heat. If they get too close, they will burn the plants and cause some damage to the plants. If the distance between the LED grow light and the plant is too far, it will greatly reduce the light utilization rate, thereby weakening the light supplement effect. Although LED grow lights generate less heat than other plant lights, they will generate a certain amount of heat. But the distance is too far, it will also affect the effect of fill light.
