How to set the right cannabis light schedules | Groplanner Tips

Everyone know that lighting is very important for growing Marijuana, but how does it affect the plant's growth? So getting a right light schedule is an important part of growing cannabis. Actually, the size and the quality of your harvest depends greatly on the amount of light cannabis plants absorbing and its timing. The seedling, vegetative and flowering stages all requires for unique lighting conditions. Different growers have their own technique for breeding, and we have tried to capture a wide range of successful strategies for implementing marijuana light schedules. In a short: Knowing about how lighting schedules influence cannabis plants is essential for growing success. In this post, we’ll talk about how to set up the cannabis light schedules.

Photoperiod Strains And Their Light Needs

The growth cycle of cannabis is only 3-5 months, and it is often grown indoors. The natural growth cycle for cannabis is to begin life in spring as a seedling, then to ''veg'' all spring and most of the summer, after which it ''flowers'' and grows buds in order to propagate the next generation. Because of this heritage, photoperiod cannabis will ''flower'' when exposed to the right darkness conditions. Each stage of a cannabis plant's life cycle has its own unique lighting requirements.

 

PPFD for Stages

Generally, cannabis plants will need approximately 100 PPFD during their clone stage, 100-300 PPFD during seedling, 300-600 PPFD during vegetative stage, and 600-900 PPFD during flowering. During its flowering stage, it could potentially take even higher PPFD(about 1000PPFD) levels if all other conditions (nutrients, CO2, temperature, humidity) are ideal. For beginner growers, 800 PPFD is a good number to aim for.(The Photosynthetic Photon Flux Density (PPFD) measures the light that actually arrives at the crop canopy in the Par zone. The amount of light that actually reaches your plants within the PAR region or the number of photosynthetically active photons that fall on a given surface each second. And the unit is in µmol/m2/s (micro moles [of photons] per square meter per second). )

 

Grow light hanging height

If a plant receives too little light (low PPFD), it will stretch towards the light source. A less-than-ideal amount of light will limit photosynthesis and total mass production will not reach maximum.

If a plant receives too intense light, the tip of its leaves will burn (turn yellow). This should also be avoided.

Keep in mind that as the plant grows taller, the lamp needs to be raised further.

We want to stimulate our plants’ photosynthesis as much as possible. It is through photosynthesis plants grow and bear fruit (buds). The right light intensity and light quality have a big impact on photosynthesis so it’s important for every grower to understand how his or her grow light should be hung to give plants the best possible conditions for maximum yield.

 

In the following article, I will combine the Groplanner grow lights, recommend the best suspension height and light schedule.

 

  • Clone Stage

Rooting clones require a steady supply of low intensity light. You want to provide a long duration of light to entrain them to stay or transition into a vegetative state. We recommend a 24/0 light schedule, with the lights remaining on full time throughout the rooting process. 24/0 lighting provides more energy for faster rooting and it also allows a consistent and stable climate during the sensitive process. However, since there is no active root system, you do not want to expose cuttings to high intensity light which can exhaust the plants beyond their capacity.

 

One of the main causes of rooting failure is providing too much or too little light. Too much light will stimulate plants to transpire more water and possibly dehydrate the cuttings. Not enough light will slow rooting, as the primary source of energy is through photosynthesis. You want to provide just enough light to satisfy the plant’s CO2 compensation point. The compensation point is the amount of light required for a plant to make enough energy to carry out daily metabolic processes such as rooting. The hanging height of your grow light will directly affect the PPFD received by your plants.

 The following table is the recommended best light settings for your clone.

 

Modle of light

 

PPFD

 

Dimming

 

Hanging height

 

light schdule

 

Groplanner I Series 640W

 

100umol/s

 

10%-15%

 

14''

 

24 ON /0 OFF

 

Groplanner O+ Series 150W

 

100umol/s

 

10%-20%

 

14''

 

24 ON /0 OFF

 

  •  Seedling Stage

Once your seed has germinated (or your clones rooted), your plant is at the seedling stage. This will last for only 2-3 weeks indoors. During this stage, your cannabis plant will be exerting a lot of its energy to develop its root system. As a seedling, your plant will transition from growing single blade leaves to growing leaves with multiple blades (also known as “fingers”) - this is an indication that the seedling stage is over.

In this stage, cannabis in the seedling stage does not require intense lighting setup. The optimal marijuana light schedule for seedlings is 18/6, meaning lights are on 18 hours per day and off (giving the plant darkness) for 6.

Remember seedlings are tiny and fragile, so you should water them accordingly. Don't overwatering your seedlings that can wreak havoc on your whole operation. The temperature of the room you have set up to grow stays between 68 and 77 degrees known as the sweet spot. Important at this stage is humidity and some growers may use humidity domes to keep the seedlings in their comfort zone.

The following table is the recommended best light settings for your seedling.

 

Modle of light

 

PPFD

 

Dimming

 

Hanging height

 

light schdule

 

Groplanner I Series 640W

 

100-300umol/s

 

15%-30%

 

14''

 

18 ON /6 OFF

 

Groplanner O+ Series 150W

 

100-300umol/s

 

15%-30%

 

14''

 

18 ON /6 OFF

 

  • Vegetative Stage

The purpose of vegetative stage is to develop the root system until it is solid and strong, as well as strengthen the main stem of the plant.

That’s not all…During this time, it is also growing out the foliage as much as possible to catch more sun and converting that into useful energy (or rather into sugar, which plant needed for energy). It needs a significant amount of light at this growth stage. The vegetative stage hosts the chemical reaction that converts light (and carbon dioxide) into sugar. It called photosynthetic.

 

Everyone knows about the process of photosynthesis, but the little known process is called phototropism.

Phototropism is responsible for informing marijuana plants where light is coming from and, therefore, helping them grow so that they are best oriented toward it. On the other hand, this also means that a too-distant light source can cause stretching in your plants. When plants stretch, they will literally reach upwards, growing taller and slenderer, to “find” a good source of light. However, stretching plants are not a good thing, and they could lead to a disappointing harvest. Therefore, the correct hang height of the grow light is so important to the marijuana at this time.

The following table is the recommended best light settings for your vegetative.

 

Modle of light

 

PPFD

 

Dimming

 

Hanging height

 

light schdule

 

Groplanner I Series 640W

 

300-600umol/s

 

30%-60%

 

14''

 

18 ON /6 OFF

 

Groplanner O Series 150W

 

300-600umol/s

 

30%-60%

 

14''

 

18 ON /6 OFF

 

Groplanner WING Series 800W

 

300-600umol/s

 

30%-50%

 

14''

 

18 ON /6 OFF

 

  • Flowering Stage

The flowering stage is the third and final phase of a cannabis plant’s lifecycle. Indoors cannabis can be tricked into thinking it’s time to flower by shortening the light cycle to 12 hours of light and 12 hours of darkness.

Indoors, when the flowering stage, you’ll want to set up a light schedule of 12 hours of light followed by 12 hours of darkness (12/12). This stage lasts for 8 to 12 weeks. Your lights should be on a constant cycle of 12/12, as any interruption can cause havoc on your grow. In fact, too much light can cause your plant to revert to the vegetative stage (“re-veg”) or even turn into a hermaphrodite.

After two or three weeks, you’ll notice changes, and your marijuana plants will show their sex. Be sure to take out the male plants as soon as you can confidently identify them.

Even though the vegetation stage is turning into the flowering stage at this point, the growth of your plant will not stop. At flowering stage, you should give enough light to your plants. Note: Don't let the grow lights burn your plants. It is why choosing a good grow light for your plant is so important. (Click here to choose a good grow light for your plants.) This will achieve the most ideal THC content.

The following table is the recommended best light settings for your flowering.

 

Modle of light

 

PPFD

 

Dimming

 

Hanging height

 

light schdule

 

 Groplanner I Series 640W

 

600-900umol/s

 

60%-100%

 

14''

 

12 ON /12 OFF

 

Groplanner O+ Series 150W

 

600-900umol/s

 

60%-100%

 

14''

 

12 ON /12 OFF

 

Groplanner WING Series 800W

 

600-900umol/s

 

50%-100%

 

14''

 

12 ON /12 OFF

 

It also depended on the varieties and numbers of your strains. The right cannabis light schedule in this article is fit for most cannabis. But every plant’s genetics are unique, so don’t be afraid of experimenting with different light schedules to find out what works best for your needs. If you have any question about the plants grow and lignting, please feel free to contact us.


Leave a comment