Best colour for cannabis flower only (2024)

FAQs

What is the best color spectrum for flowering cannabis? ›

The blue light spectrum between 400 and 500 nm is optimal for cannabis plants throughout their vegetative phase. At 460 nm, plants receive the signal to produce resilient, broad leaves. During flowering, red light with a wavelength between 620 and 740 nm can be used to maximize yield.

Red light encourages flowering, which makes it important for plants grown for their fruit or flowers.

Anywhere between 2700K and 3500K is generally what people use for flower. Often people go in the range of 3000-4000 for an all-around light, but if flowering is the only use planned for the light 2700K will work great.

That stands to reason, because the majority of cannabis is green in its optimum state. However, you might be shocked to realize that it isn't the only color you could find in your weed grow. You can find buds in vibrant orange and red colors, or you may stay with colder hues like purple, blue, and even black.

Therefore, blue light is one of the most important lights for vegetative growth, and most growers recommend blue light during the earliest grow stages. Blue light has a massive effect on chlorophyll formation, which helps plants absorb light.

Blue light has many similar effects as the UVA light. Blue photons however carry less energy compared UV, therefore the responses of blue can be milder than those of UV. However, blue light has been shown to increase cannabinoid concentrations, especially THC, as demonstrated in the article by Magagnini et al.

Red light, when combined with blue, allows plants to flower. Knowing that different colors of light can affect what a plant does is important in a world that depends on plants for food. Advanced LED technology is now making it possible to control the kinds of colored light we provide plants in controlled environments.

The colours of visible light form a colour wheel. Within that wheel the colour an object appears to be is the colour complementary to the one it most strongly absorbs. As such, plants look green because they absorb red light most efficiently and the green light is reflected.

Blue promotes root development and strong, stocky plant growth. When you blast your young plants with blue, you prepare them to sustain a ton of buds in the future. Red light, on the other hand, does its best work in the flowering phase. A higher intensity of red promotes a higher yield.

The outside temperature for cannabis plants should remain above 40 °F (4 °C) for optimal growth.

Is 81 degrees too hot for flowering cannabis? ›

Best grow room temperature for the flowering stage

You can have daytime temps of 72-81 if you supplement with CO2. Growers should reduce the relative humidity to 65-70% during early flower, 55-65% in mid flower and 45-50% for the last two weeks before harvest.

Flower Room Humidity and Temperature

The ideal cannabis flowering humidity is between 40% to 60%. During flower, lowering your relative humidity level can help prevent mold and mildew from forming. To accommodate the lower RH, cooler temperatures will also help you maintain your ideal VPD.

For most cannabis harvests, growers look for a certain ratio of cloudy trichomes to amber trichomes. Many expert growers believe that the best time to harvest a plant is when the trichomes are 70 percent cloudy and 30 percent amber.

Quality cannabis has a healthy green color and can have touches of red, orange, and purple all depending on the strain. Bad buds look old — it's a muted green, brown, tan or even yellow, and if you spot anything that looks like mold, don't buy it.

Excellent Bud Structure

If you want to know what good weed looks like, look for buds or nugs that look springy rather than flat and aren't full of stems and seeds. An ideal trim job will ensure that you get as much of the good stuff as possible without any excess leaves, stems, or shake.

Flowering Stage

Turn your red light spectrum—that's red and deep red—up to 100%. This maneuver helps you get those higher-than-ever yields.

Red light, with wavelengths ranging from approximately 600 to 700 nanometers, is a critical component for plant growth. Red photons are the most photosynthetically efficient of all and therefore indoor growers want to maximise the amount of red in the grow light spectrum.

Red light promotes production of buds and flowers and decreases maturation time, while blue light promotes more leaves, better bud quality and tighter, sturdier growth. Plus, with overhead-only lighting, the lower parts of the plants are usually looser and less lush than the canopy.

In conclusion, full spectrum grow lights may be effective for vegetation, but they're not always the best choice for blooming and fruiting. If you want to maximize your yield and produce high-quality flowers and fruits, invest in a grow light that's designed specifically for these stages of growth.