When growing indoors, it’s essential to match the natural sunlight changes throughout the seasons to initiate the different growth stages of each plant. Different temperatures surrounding a plant and the intensity of the sun are triggers for plants that allow them to release chemicals internally that will start them off into the next stage of their lifecycle.
The size if your indoor garden space, as well as the plants you are planning on growing will determine the type of lighting, and the strength of lighting you should use.
High Intensity Discharge (HID) lights are the most popular choice for most indoor growers, and HID setups usually consist of:
- Bulbs – Usually Either Metal Halide (MH) or High Pressure Sodium (HPS)
- Ballast – This is used to allow the control a constant and consistent stream of electricity through the bulbs.
- Lighting Hood or Lighting Reflector – This is used to spread the light and the heat being emitted from the bulbs evenly around your grow room so that there are no “heat spots” and so that the light can be distributed further – reducing the need for multiple bulbs.
Traditional Grow Lighting Systems
MH – Metal Halide Bulbs
These bulbs emit wavelengths towards the blue/white end of the spectrum which imitates the hotter summer sun.
Metal Halide Bulbs should be used to during a plant’s growth phase. After the initial germination of your seedlings, your plant needs very warm temperatures to b able to grow to their full potential.
There are some plants that can grow to maturity just using MH bulbs, including leafy vegetables and herbs.
Most plants will flower in MH bulbs, but the yields you will gain from using this one bulb on its own is unlikely to be as high as using them in conjunction with HPS Bulbs.
Learn More: Metal Halide Grow Lights Explained and Reviewed
HPS – High Pressure Sodium Bulbs
HPS bulbs have an orangey red tint to them, imitating the warmer colours of autumn and fall used primarily for the flowering stage of a plants life.
This will be the time when your vegetables and fruits are starting to grow, and when plants should start flowering.
If you are planning on using HPS bulbs in on your plants, you will need to switch over to using these as soon as your plants start flowering.
MH & HPS bulbs are the choice for many indoor growers as their effectiveness for the vegetative and flowering stage of all types of plant growth has been proven.
MH & HPS are very cheap to buy, however both bubs do generate a lot of heat and therefore require a high amount of energy to run – so energy bills will potentially be higher than alternative lighting systems.
Wattage for MH & HPS
The wattage of the bulbs in your grow room will be determined by the size of the room as well as what you are trying to grow.
A general rule is that the larger the size of the grow room, the stronger the wattage that will be required.
Below is a guide for wattages based on room size, as well as the distance the bulb should be from the top of the plant.
The types of plants you are trying to grow will also determine the wattage in your grow room. High-light plants like tomatoes will need a strong bulb that low-light plants like herbs and lettuces.
New Types of Indoor Lighting Systems
Fluorescent lights give off a cool blue light which is ideal for seedlings and cuttings. Fluorescent lights provide a wide angle of light, and emit low levels of heat, which creates good conditions for the first stages of a plants lifecycle.
Compact Fluorescent (CFL) – Compact Fluorescent lighting is a type of fluorescent lighting that consists of a small fluorescent tube or multiple tubes, where the ballast is integrated into the lighting. Compact Fluorescent lighting is therefore ideal for very small grow rooms, or grow areas.
Because of their low output, fluorescent lights are relatively inexpensive to run, and choosing CFL’s means there is no need to purchase separate ballast – reducing your costs further.
Fluorescent lighting is only suitable to stimulate growth in seedling and young plants, as their output is very low they don’t generate enough heat to provide an effective lighting solution beyond this stage.
Learn More: T5 Grow Lights Explained and Reviewed
LED Lighting is a type of lighting system that is relatively new for indoor growing. The initial expense of LED lighting is high in comparison to other types of hydroponic lighting. However, they are highly energy efficient and the bulbs can last for years (in comparison to MH & HPS which may only last one season).
LED lighting also emits far less heat than traditional bulbs which means they are good for very small growing spaces where the bulbs have to be very close to the plants.
Just like traditional bulbs – LED lights can be bought that emit different spectrums of light which will help to produce optimum efficiency in the different stages of a plant’s lifecycle.
RGB or Multi-colour LED’s can also be bought, and these types of lights can offer any spectrum of light by “mixing” the primary colours. The same LED bulbs can be used at each different stage of the plants lifecycle by using different filters, eliminating the need to switch bulbs during the plant’s growth.
Sulphur plasma lighting systems are very new in the world of hydroponics lighting.
Sulphur plasma bulbs provide adjustable output that can simulate wattage from 100w to 1300w.
This means that you are able to use the lighting with multiple types of plants, in different sizes of grow rooms. These types of bulbs are highly energy efficient and manufacturers and many users claim that the bulbs can imitate the natural light to a much greater extent than traditional bulbs by delivering a full and continuous spectrum of light.
Because sulphur plasma lighting is relatively new in the industry, it’s yet not clear how effective these types of bulbs are for indoor growing. The bulbs are currently not easy to get hold off and are very expensive to buy.
Learn More: Plasma Grow Lights Explained and Reviewed
What’s your favorite type of lighting to use for hydroponic grows? Let me know in the comments!
I’m the founder of Epic Gardening, a website dedicated to teaching 10,000,000 people how to grow plants. I enjoy skateboarding, piano, guitar, business, and experimenting with all kinds of gardening techniques!