Direct sunlight is incredibly important for growing cannabis plants. While other plants may do just fine placed beside a window, cannabis won’t grow nor flower indoors without the help of artificial lighting. These plants need intense light.

When growing indoors, your grow lights act as the sun; in this section we’ll go through everything you need to know about indoor lighting.

Indoor Grow Lighting

The first thing that you’ll need to know is that the yield you’re going to get depends on the size of your grow. When we talk about a light being more potent, it’s because it covers a wider area. For example, a 600w HPS lighting system could cover a 120x120 cm grow tent, and a 400w lighting system could cover 100x100 cm.

Another factor to keep in mind is that the quality of your flowers depends on the climate conditions in your grow tent or grow room. The lights give your plants the light they need but they also increase temperature, which can increase humidity.

Excess heat when flowering your plants destroys the terpenes produced in the buds, which are responsible for cannabis flavour and aroma.

Humidity is another important factor; high humidity levels are an open door for fungi and other infections in flowers.

How to Pick the Best Indoor Lighting System for Cannabis

Before choosing your lighting system, keep in mind that you’ll be paying for your lighting kit once but your electric bills are monthly. Spending a little extra on a system that has a decent ratio between yield and energy consumption will allow you to save money in the long run.

After just a few months you’ll have made back your initial investment in flowers.

Another thing to keep in mind when choosing a lighting system is that, if you want to harvest high quality buds and large yields you’ll need to invest in decent lighting in your grow. If you don’t get the right kind of light, you won’t be able to make up for it with watering or fertilizing, you’ll end up ruining your strains and using materials for no reason.

What Types of Grow Lights Are There?

There are four types of lights used when growing cannabis indoors.

Energy-efficient Lighting for Cannabis

  • Fluorescent lighting is incredibly helpful, especially when it comes to the veg period of cannabis or for maintaining mother plants and clones.
  • You can also use this type of lighting for the flowering period in small grow tents – 60x60 cm or 80x80 cm. However, in larger grow tents they lose efficiency.
  • Energy-efficient grow lights are the best choice for those that don’t have much space.
  • Available in tubes and CFL lights – Compact Fluorescent Lighting.

HPS (High Pressure Sodium) Lighting

  • These are the most used when it comes to growing cannabis indoors.
  • Low-cost lighting.
  • These used to be the only types of lights that you could use in 1m2 and larger grow tents (although this has changed in recent years).

However, this type of lighting is the least efficient type. HPS lights use the most electricity and generate the most heat.

  • They require a ballast that matches their wattage in order to work properly.
  • If you’re going to be growing in spring or the summer, you’ll need to have a source of cold air in your grow room – a great way to facilitate this is by using an AC unit.

LEC/CMH Lighting

Also called ceramic metal halide lighting, these lights produce an optimal light spectrum that includes ultraviolet and infrared lights.

  • They need a reflector as well as a ballast and a special socket.
  • Efficiently uses electricity.

If, when using a HPS system you can harvest about 0.8g per watt used, LEC systems can produce between 1.5 and 1.8 grams per watt used.

  • A 315w LEC lamp is almost just as good as a 600we HPS light, using less electricity with a better light colour including UV and IR rays.
  • Produces less heat than a HPS system.

LED Lighting for Grow Tents

LED lighting has dramatically increased in quality in recent years. A few years ago they weren’t capable of producing the same yields as other systems, but now they’re the best option for home growers that need large yields.

  • LED technology allows you to grow in a 150x150 cm area using just 600w.
  • They generate less heat than other types of grow lights which reduces expenses including running the extraction fan and air conditioning systems.
  • There are LED panels for all grow tents from 80x80 cm onwards.

What Lights do I Need for my Grow Tent?

The strength of your lighting system is directly related to the size of your grow tent. Lighting for a small 60x60x158 cm grow isn’t going to be the same as lighting for a 120x120x238cm grow tent.

The difference in eight allows you to use more potent grow lights, which might end up burning the tips of the leaves of your plants in small grow tents due to the proximity.

  • For a small 60x60x158 cm grow tent you’ll need to use compact fluorescent lighting.
  • For a 80x80x180 cm grow tent you can choose between 400w HPS or 200w LED lighting.
  • For a 100x100x200 cm grow tent, 400w HPS or 300w LED lighting.
  • For a 120x120x200 cm grow tent or taller you can go up to 600w HPS, 4655-480w LED or a 315w LEC system.
  • For a 150x150x200 cm grow tent or taller you can use 1000w HPS, 600w LED or a 630w LEC light.

Grow Tent Reflectors – Which to Choose

Reflectors are used to make the most of the light in your grow room so that your plants can develop successfully. Light comes out of your lighting system in all directions, and a decent reflector can take that light and redirect it towards your plants.

There are various types of reflectors, from the most basic hammertone finish reflectors to those that have a winged structure that allow growers to increase the lit area.

When it comes to choosing a reflector, you’ll need to keep in mind its reflection percentage; the higher the better. The most advanced models come with a dissipator that distributes light while also getting rid of any hot pockets of air.


Some lighting systems such as sodium lighting (HPS) or metal halide lighting need ballasts to start up and be used efficiently – they can’t be plugged into the mains. There are two different types of ballasts.

Analog Ballasts

  • Analog ballasts are affordable and do what they’re supposed to, but they consume more electricity.
  • These ballasts were the first type to be used and were the standard ballast for many years.
  • They’re noisier and less safe than the electric models.
  • More advanced models have a fuse but they don’t have the same protective measures as electronic ballasts.

Electronic Ballasts

A few years ago, ballasts were simply something needed to grow cannabis plants indoors, although with the arrival of electric models they’re also used for other things; modern ballasts don’t just turn on and off, they also allow you to choose the wattage they work at.

For example, with a 600w ballast and lamp you can start growing at 25% and save on electricity because your plants are small and don’t need as much light. As your plants grow older you can increase the wattage used by the ballast and bulb.

All of this plus the fact that they use less electricity make electronic ballasts a great investment that you’ll make back straight away.

Other Accessories for Indoor Grow Lighting

  • Timers: in order to keep your lighting and other electrical systems on an automated timing system you’ll need to get a timer.
  • Control panel: this is handy for large grows that are running various systems at once.
  • Pulleys: In order to hold up your lamps and adjust their height whenever needed – make sure that you keep the weight of your system and strength of your pulleys in mind.
  • If you’re going to be working under HPS lighting for a long time or if you want to get into the tent with LEC and LED lights on, you’ll need to protect your eyes using UV protective glasses.
  • In order to grow efficiently using LED lights we recommend using a digital luxometer, which will allow you to set the perfect LED height.
  • Other electrical accessories such as plugs, cables and sockets.

Indoor Cannabis Grow Lights

Getting a full lighting kit for indoor growing is a great way to save both money and time. The kits on our web-page are designed in order to provide a balanced experience and to make the most of the materials used at quite a convenient price.

At La Huerta Grow Shop we stock Complete Grow Lighting Kits that come with everything you need to set up your indoor grow lighting.

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