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One of the fun things about keeping indoor plants is that you can regulate their environment. Because plants grow even better under LED grow lights.
We have noticed that some newbies are asking questions about indoor grow lights LED. Plants grow faster if they can get a full day of light, right? Can I leave my grow light on 24 hours?
Honestly, it is definitely not recommended to keep the LED grow lights working 24 hours a day. Firstly, too much light is not good for plants. Secondly, it will make you consume more electricity, even if it’s a small wattage bulb, but it’s not necessary.
While continuous light may increase the production of greenhouse food. But plants also need periods of darkness to properly regulate their growth and repair damaged tissues, produce hormones and store energy. If a plant doesn’t have any dark periods, it will experience stress and damage, leading to stunted growth, wilting, and even death.
Have you ever thought about how long to leave a grow light on?
How Many Hours Should Grow Lights Be On?
The standard answer is that the operating time of LED grow lights depends on the light required by the plant. In general, plants need about 12-16 hours of light and 8-12 hours of darkness per day.
The range interval of 12-16 hours may be baffling.
- Some plants only need 12 hours. If your grow lights work for 15 hours, the plant will wilt and die from too much light.
- Conversely, some may require 16 hours. If your grow lights only work for 12 hours, the plant will suffer from a lack of light and its growth will be stunted.
Light Requirements for Plants
The amount of light a plant needs depends on the plant species.
Many plants need about 12 hours of light per day to grow and thrive. Most plants need a certain amount of light for photosynthesis, which converts light energy into chemical energy to promote their growth and metabolism.
LED grow lights are definitely essential for where there is not enough light indoors.
- Roses. In general, rose production can be increased by using continuous light. Shade-tolerant varieties grow well in less than 6 hours of sunlight per day.
- Tomatoes. Tomato plants need a lot of light to produce healthy, tasty fruit. They usually need 12-16 hours of light per day.
- Cucumbers. Cucumber plants also need 12 hours of light daily to produce healthy, tasty fruit.
- Peppers. Like tomatoes, peppers need about 12-16 hours of light per day to thrive.
- Cannabis. During the growing stage, cannabis plants need 18-24 hours of light per day from indoor grow LED lights. During the flowering stage, cannabis plants need 12 hours of light and 12 hours of darkness per day.
- Succulents. Your clip-on grow lights for indoor plants can work for 14-16 hours per day during the active growing season of your succulents, reducing them to 8-10 hours per day during the dormant season.
- Herbs. For outdoor growing, most herbs need at least 6 hours of direct sunlight per day, while basil requires 8 or more hours of light. Growing indoors allows LED grow lights to work 12-16 hours per day.
- Lettuce. Under indoor grow light kits, seedlings need about 14-16 hours of light per day. As plants mature, they may require slightly less light, about 12-14 hours per day.
- Strawberries. For outdoor growing, you will need about 10-12 hours of light per day. For indoor growing, keep your lights working for 14-16 hours.
Growth Cycle of Plants
The amount of light a plant needs depends on the growth stage of the plant.
Plants require different light or spectrum intake at each stage. It is a good understanding that humans require different nutritional requirements at each stage from infancy to adulthood.
The same goes for plants. Each stage of growth, flowering and fruiting requires a different amount of light. Let’s go on to learn more about how much light is needed for the following stages of plant growth.
Cannabis
Vegetative Stage
Your growing weed indoors light needs to work for 18-24 hours during the period when the plant is growing leaves and stems. This extended period of light allows the plant to photosynthesize and produce the energy needed for the growth and development of leaves and stems.
In terms of light intensity, hemp plants require 1000-1500 micro-moles per square meter per second (μmol/m²/s) during the growth phase. The specific light intensity required may depend on factors such as the genetics of the plant, the growing environment and the specific growing method used.
Providing the right amount and intensity of light at this stage is crucial to ensure healthy plant growth and development. That’s why choosing the right LED grow lights for your plants is a key point for growing cannabis indoors.
If the plant does not receive enough light, it may become weak and skeletal and not produce optimal yields. Conversely, too much light can cause the cannabis plant to experience light stress, which can damage the leaves and negatively impact growth.
Flowering Stage
As cannabis begins to produce buds, it needs a specific light cycle to trigger the production of flowers or buds that will make it produce flower buds. Cannabis plants require 12 hours of light and 12 hours of darkness per day.
In terms of light intensity, cannabis plants require 600-800 micro-moles per square meter per second (μmol/m²/s) during the flowering stage. This level of light is slightly lower than that required for the growth phase, as the focus of the plant has shifted from asexual reproduction to flowering production.
Tips
- It is important to maintain this 12/12 light cycle throughout the flowering stage. This is because any interruption in the light cycle may negatively affect the plant’s ability to flower or bud.
- Today, growers know that UV light can increase the cannabinoids in cannabis plants and also improve the plant’s resistance to pests and diseases and improve their overall growth, odor and yield.
- Some R&D LED grow lights manufacturers will produce plant lights that are more conducive to cannabis growth based on the customer’s requirements and the specific spectrum of the plant. And you can see there are also full spectrum plant lights with UV light on the market. If you care about this, you can try to talk to Auxgrow.
Strawberries
When growing strawberries indoors with commercial greenhouse lighting, also has different light requirements for each stage of the growth cycle.
Germination Stage
Starting from the seed, strawberries need low to medium light. It is best to provide them with about 12-16 hours of light per day.
Vegetative Stage
During the growth stage phase, strawberries require higher light levels. It is recommended to provide them with 14-18 hours of light per day.
Flowering Stage
Strawberries need more light than in the growing stage, ideally 16-18 hours of light.
Fruiting Stage
Strawberries rushing into the fruiting stage need moderate to high light levels. Please keep your lights working for 12-14 hours.
Tips
- You will eventually have to monitor the actual growth of the plants and adjust the light level or the height of the LED grow lights accordingly to meet their changing light requirements at each stage of growth.
- Both wild strawberries and June strawberries have different light requirements. So it is best to research the specific needs of your particular plants to ensure they receive the proper amount of light.
Succulents
A good rule of thumb is to provide 14-16 hours of light per day during the active growth period of succulents and reduce it to 8-10 hours per day during the dormant period.
Germination Stage
Succulents need bright, direct light for successful germination. Indoor house plant grow lights with an intensity of 200 to 400 micro-moles per square meter per second (µmol/m²/s) and a color temperature of 5000K to 6500K are ideal for this stage.
Vegetative Stage
In this stage, succulents require more intense light than in the germination and seedling stages. Indoor herb growing light with an intensity of 400 to 600µmol/m²/s and a color temperature of 5000K to 6500K is ideal for this stage.
Flowering Stage
At this stage, succulents need the most intense light. Indoor growing lights for plants with an intensity of 600 to 800µmol/m²/s and a color temperature of 2700K to 3000K are ideal for this stage.
Tips
- Some types of succulents can tolerate much less light. It’s best to research the specific needs of your particular plants to make sure they are getting the right amount of light.
- Be sure your succulents are not getting too much direct sunlight. If you notice signs of sun damage such as brown spots or burning on the leaves, you may need to move your succulents to a slightly shaded area.
Can Too Much Light Stunt Plant Growth?
Have you ever heard of the Chinese Analects of Confucius – Zilu, that if you want to be fast, you will not achieve your goal? When you see only small benefits, you will not achieve great things.
As we mentioned, some newcomers ask whether it is possible to leave a grow light on 24 hours a day so that the plants can quickly reach the development and fruiting stage. He only wants to reach the plant’s maturity quickly and ignores the problem that too much light can cause the plant to wilt or even die.
Photo-Oxidative Stress
Running LED grow lights 24/7 means that intense light exposure can cause damage to plant cells by producing reactive oxygen species (ROS). This can lead to reduced growth, stunting, and even cell death.
Degradation of Chlorophyll
Chlorophyll is the pigment responsible for capturing light energy in photosynthesis. Excessive light exposure can lead to the breakdown of chlorophyll in leaves, which may result in reduced photosynthetic capacity and slower growth.
Burnt Leaves
Leaves of plants may be burnt or scorched by leaving indoor grow lighting on 24/7. Reduced photosynthetic capacity of plants.
Less Efficient Use of Water
Plants exposed to too much light may also lose more water through transpiration, and plants will be at risk of drought stress.
Reduced Nutrient
High light levels can also cause damage to the roots of plants, which may reduce their ability to absorb nutrients from the soil and stunt growth and development.
Conclusion
The optimal operating time for LED grow lights depends on several factors, including the type of plant being grown, the growth stage of the plant and the intensity of the light source. In general, most plants require 14 to 18 hours of light per day during the Vegetative stage and 12 hours of light per day during the flowering stage.
It is important to monitor plants and adjust lighting schedules as necessary to ensure they receive the right amount of light for their specific needs.
Likewise, it is essential to note that excessive light can be harmful to plants, causing stress and stunted growth. We recommend using a timer or LED grow light controller to ensure consistent light and provide enough dark time for plants to rest.
