Plants need light to grow. The light must have the proper spectrum and intensity to ensure strong and healthy growth. Light is made up of a variety of spectral colors, each of which provide your plants a signal for a particular kind of growth. Outside, the sun’s position in the sky changes throughout the course of the year and as a result the color of it’s light changes. In the summer the light is more in the red spectrum and in the winter it is more in the blue spectrum. Plants have evolved with the earth and their growth patterns will change in relation to this. Growing indoors under artificial lighting is pretty much the same.
The bulbs that you will use in your fixture(s) also come in different spectrums. Generally HPS (High Pressure Sodium) bulbs produce an orange light, if you live in the city you see these everyday. MH (Metal Halide) bulbs produce a light more in the blue spectrum. However, indoor growing has evolved greatly over the years and these general rules don’t always apply. You can buy bulbs today that range from 2k to 10k that will cover every stage of growth. To learn about indoor lighting in more detail select from the menu below, where we have provided a lot of very specific information to help you calculate how much light you will need based on the square footage of your space.