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The Light Spectrum Matters When Growing Cannabis


The light spectrum is very important to the cannabis growth cycle. The type and color of light given to your cannabis plants determines how well it grows. Can you use just one light throughout the whole process? Sure, but you aren’t likely to get the best results possible.

This simple guide will help you give your cannabis plants, if homegrowing is permitted where you live, the right light at the right time in its growing cycle.

Blue Lights

If you need your plants to be short and stocky, blue lights will help you achieve that. They are cooler lights, which also help with terpene and trichome production later in the flowering stage. Using blue lights close to harvest time, along with a cooler grow temperature, can help you produce crops with purple hues. These are attractive to market consumers.

Red, Far Red and Infrared Lights

Red lights tell your plants its summertime. These make your plants grow taller (stretch). Since this spectrum promotes budding, if your plant really isn’t ready for the flowering stage you may not end up with the best crop. Once your plant shows signs of starting the flowering stage, switch to red spectrum lights. It’ll help make the flowering stage go a little faster for you too.

Yellow Lights

Yellow lights promote germination and long stems. They also help throughout the flowering stages and may increase bud production slightly. Plants that are kept mainly under HPS lighting end up having yellow or gold color hues to them, even in the buds. It doesn’t mean it’s a bad crop; it’s just due to the lighting given to the plant.

Purple Lights

Most LED lights emit a purple hue. What this does for your cannabis plants is help them grow fatter buds. That’s always a good thing. Using a mixed spectrum light, such as a purple grow light, helps penetrate your plant to give it more energy for stronger growth and bigger yields. The crops harvested from purple light use can have a better flavor as the blue inclusions help produce more flavonoids (terpenes), enhancing the flavor.

Green Lights

Lights in the green spectrum help your plants grow because it penetrates further into the plant than blue or red lights. Fluorescents with a small amount of green spectrum included will work if you really can’t scrape the pennies together for an actual green spectrum light.

But, you only want the exposure of green light to be minimal because your plant needs other spectrums of light more.

All lights, except some LED lights have some green spectrum in them.

Final Thoughts

Many cannabis growers are switching to LED lighting setups for their efficiency and low energy costs for indoor cannabis growers. Cutting growing costs is important for commercial growers and caregivers to ensure that they can maintain their business. Producing the biggest yields of the highest quality cannabis is a must, using the right lighting at the right stages of growth helps meet those goals. The more consistent a grower is with their lighting setup, the better the entire climate will be for the cannabis plants to grow strong and full of buds.

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