But can you simply stick a cannabis plant in a nice sunny window and let it do its thing? Read on to understand what to expect if you choose to grow cannabis indoors au naturel, along with a few tips and tricks from experts to help your indoor plant thrive in a minimal setup.
One reason indoor growers work so hard to manipulate the growing climate with light-, temperature-, and humidity-control systems is that different cultivars have different needs and preferences.
Successfully growing a cannabis plant indoors is all about covering the plant’s basic needs: air, light, temperature, water, and nutrients. So, if you get those things right, your homegrown cannabis plant could provide much more than a fun experiment. And considering that indoor cannabis plants can grow a few feet tall and equally wide, you should anticipate young plants to take up more space by the time they reach maturity.
During the vegetative growth phase — when plants are establishing the foliage that’ll drive photosynthesis over the course of their life cycles — indoor growers make sure to give their plants lots of blue light. In the past, that meant using metal halide (MH) lamps that were rich in blue wavebands. Now, growers can select an optimized LED spectrum or an LED fixture with tunable wavelengths. Spectrum tunability allows cultivators to increase — or decrease — the amount of blue light they’re providing their plants as the production cycle changes.
When cannabis isn’t getting enough blue light, it’ll compete for exposure by growing longer shoots and eventually exhibit leaf hyponasty (an upward curl of the leaf surface). That’s not a good thing — at least not in the opinion of indoor cultivators who want short, manageable plants. Without any blue light, plants get unruly, tall, and poorly adapted for flowering. Because they’re busy stretching for light, they fail to develop the root system that’ll support their nutrition when it’s time to bloom.
Blue Light for Cannabis
But when we look at horticultural lights, pure blue light won’t seem as bright as other colors. Our eyes are less sensitive to blue and more sensitive to mid-spectrum wavelengths like green. That’s why a light with lots of blue will seem less powerful than it actually is. If light were to produce only blue light, it’ll appear dimmer than a light-producing only green or amber light. Yet blue light matters to plants, even though we can’t see it that well.
When we talk about colors of light, we’re really referring to their wavelength; it’s the wavelength of a light source that makes it appear blue, or red or green. The visible light spectrum spans from violet/blue light which has short wavelengths (ranging from 400-500 nanometers) to red light, which has the longest visible wavelength of around 700 nanometers.
How Blue Light Effects Cannabis
At the end of flowering, in the final 3-7 days, growers return to a spectrum with lots of blue light. Sometimes, they switch bulbs from HPS back to MH (if their ballasts are compatible). Or — if they’re running tunable LEDs — they can simply change the settings on their controller.
Providing Insufficient Lighting
It is important to consider the scale of your operations. Think about how many plants you’re growing and how many LED lights you’ll need in order to illuminate them properly. You should also be aware of the luminosity of the lights you’re using. For example, a 200W LED light is said to be sufficient for a yield of about 100 grams. Make sure that you have enough lamps but still look for a good balance between providing sufficient lighting and not overdoing it.
In this article, we’ll provide you with the 10 most common things you should pay attention to when using LED grow lights so you can grow healthy looking plants and avoid any unnecessary hassle. This information is extremely relevant to beginners.
Setting the Lamps at an Improper Distance
Overheating or insufficient lighting can result from having too many or not enough lights, but it can also result from placing the lights too close or too far from the plants. There is no universal rule for setting the distance but it’s recommended that LEDs are placed 12 to 18 inches away from the plants.
Source: Maximum Yield, May 31, 2019
Overwatering When Switching from HIDs to LEDs
Regular HID lights produce a lot of heat and generate lots of infrared light. This dries out the plant and the soil and results in the need to water the plant more often. However, LED lights generate no infrared light and don’t emit nearly as much heat, so there is no need for abundant watering.