Light Cycle Basics for Growing Weed
There are articles and tips everywhere on the web giving advice on the right light cycle basics — understanding lighting spectrum for your plants during each growth phase, and also on the right amount of light to give your plants during each growth phase. Unfortunately, many of these articles seem to disagree with each other or proving a conflicting answer. So, what is the right answer? First it is important to make sure you have the light cycle basics correct:
- Buy good quality LED grow lights, not cheap spots
- Use full spectrum lights that also have the right red and blue spectrum
- Make sure your lights deliver enough Lumens for the size of your room
- Mount them so you can keep them the right level above your plants
Without these basics you will not succeed, no matter what lighting cycle you set!!
Once you have the right equipment in place and set up correctly, there are basically three growth phases that each require slight adjustments in the lighting cycle:
Seedlings – The lighting intensity is not as important during this phase as the plants are building their root system and as long as they are getting 16 hours of light daily and 8 hours of darkness they will grow fine and the light cycle during this phase is not critical in determining the quality of your plants during the flowering stage.
Vegetative – During this phase your plants are growing fast and developing the strong stems and leaves that they need to develop the buds your are aiming for. During this phase you want to deliver full spectrum lighting for your plants, but blue lighting in the 400-500 nm range is critical to support the plants photosynthesis process. During this phase you can maintain 18-24 hours of lighting daily, for at least 4-6 weeks depending on your setup. Eighteen hours is fine for a few plants,but you may want to go to 24 hour lighting for a “screen of green” setup. As long as you maintain that consistent 18-24 hours of light daily your plants will continue to think it is summer and continue to grow strong and large leaves and stems. This will be great for the mother plant you are cloning from but will be a problem for the plants you want to develop great buds.
Flowering – Once your plants show signs of being ready for flowering you will need to modify the light cycle to initiate the flowering phase. Go to twelve hours of light and twelve hours of darkness for the entire flowering phase. Also, make sure your red light spectrum is strong and if available this is when ultraviolet lighting is sometimes added. The lighting quality and spectrum is most important during this phase as this is the phase when the buds you are growing develop and mature.
Seedling – 16 hours of full spectrum light
Vegetative – 18-24 hours of full spectrum with strong blue spectrum
Flowering – 12 hours of full spectrum with strong red spectrum