Part 2: The right way to use grow lights
In the previous post, we have learnt the different types of grow lights which are available. In this post, we will learn how to use them in the correct way to gain maximum benefits from them.
We have established why plants need light to grow and survive. They need light in a proper wavelength and for a specific duration. Now comes the next question –
Where to position the lights?
The first thing that comes to our mind is where to place them, at what angle, and what should be the distance etc. So here are all the answers to all your questions. You are using these lights to replicate the sun, kind of like an artificial sun. Place them directly above the plants so that the growth of the plants is upright. As plants are attracted to light and will grow in the direction of light, it is advisable to place them directly above the plants. In the case of creepers, it doesn’t matter as they will grow in the direction of support.
How much distance should be there between plants and lights?
Now, this depends on the type of lights. If you are using traditional or incandescent bulbs, better keep them at a safe distance from your plants. They emit a lot of heat and it can be harmful to the plants. If you are using LEDs or fluorescent lights, you can keep them close to the plants as they emit less heat. Fluorescent lights give out more heat signature as compared to LEDs, hence should be kept a little more away.
Traditional or incandescent bulbs – 24 to 30 inches
HIDs, LEDs or fluorescent lights – 6 to 12 inches
Which colour is best for my plants?
We all are familiar with the seven colours of the rainbow. In short, they are abbreviated as – VIBGYOR. This range of light is also known as PAR or photosynthetically active radiation which is required for photosynthesis. We need grow lights to provide PAR to plants with an appropriate wavelength for desired period of time. So, let’s see what colour of light plays what role in a plant’s life?
Violet/Blue light – This colour is important for growth, photosynthesis and cholorophyll formation. This colour is directly related to the vegetative growth of the plants so it will be required at all times and in almost all plants. Blue light is essential for germination of seeds and it stimulates growth of stronger roots too.
White light – When all the colours of a rainbow are combined it gives out white light. It is responsible for growth of leaves. So, if you growing any leafy veggies, salad greens or microgreens, white light is a must which can be turned on after germination. If you are using grow lights for ornamentals, then white light is necessary because most of them are foliage plants.
Orange/Red light – This spectrum is important for flowering and fruiting of plants. So after a few weeks of sowing, look up for the days to flowering for the plants you are growing and start giving them this spectrum of light 5 to 7 days before in order to produce flowers and then fruits. Basically, all the veggies, fruit trees and indoor flowering plants will require this spectrum.
Note: White light has all the colours of the spectrum but that doesn’t mean you need to just provide white grow lights. Certain colours are harmful and will inhibit many processes in a plant. This small yet important knowledge of lights will help you plan better and will keep your plants healthy. Green light is not at all useful as plants reflect them, that’s why they are green!