Selecting Grow Room Lights for Maximum Yields

One of the major perks to an indoor grow setup is that you get complete control over your plants’ light schedules, allowing you to manipulate their stages of growth and more importantly, the volume and quality of bud you get after a successful harvest.

Growing cannabis indoors can be tricky, especially for beginners, because there is so much to understand when it comes to lighting and grow lights, and such little margin for error.

Not to worry, Skyline Grow Shop has you covered with simple advice on how to choose the best grow lights for your needs and budget.

How Wattage Affects Yields

The right lighting is directly tied to plant growth and bud production, with that said, if you aren’t getting the yields you expect, looking to your light kit is generally a good place to see where you can make improvements.

600-watt HID lights generally provide the ideal light needed for a healthy and bountiful crop, but there is room for flexibility with regards to wattage and lighting type. 

Technically even a 250-watt HID can do the trick for small setups (though it is not recommended), while many growers prefer to use 1000-watt lights to improve results where large amounts are grown.

The point is that there is no straightforward answer to how many watts you should opt for, it depends on what you want to do, how large the grow area is, and how much you are willing to spend on running electricity costs.

A Formula for General Illumination

The following is a formula you can use to determine how many watts you need (with an HID grow light) depending on the size of the growing area:

• 250 watts = 0.5 meter X 0.5 meter area
• 400 watts = 0.9 meter X 0.9 meter area
• 600 watts = 1 meter X 1 meter
• 1000 watts = 1.2 meters x 1.2 meters

The yields also depend on the genetics of the strain being grown, if the genetics results in poorer yields, not even a 1000 watt HID will improve this, so the genetic quality of the plant is also something you should account for. Keep in mind, however, higher wattages mean more electricity consumption, especially in the case of HID and fluorescent lights.

Colour Bands & Plant Growth

The color temperature given off by a light is also an important factor to consider. Certain spectrums are better for growth, while others do nothing. On top of that, the plant will benefit from different colour temperatures at different stages of growth.

The following colour rendering index shows how different colour temperatures or CCT (measured in Kalvin) replicate certain types of natural light, and can be referenced when purchasing grow lights:

Colour Rendering Index

5000 K- 8000 K

Produces a blue light, ideal for encouraging healthy growth of leaves and stem.

4000 K – 5000 K

Emits a light-blue light, also ideal for the healthy growth of leaves and stems.

4000 K

Produces a neutral white light. Good for normal plant growth.

3700 K – 4000 K

Emits a warm neutral light. Ideal for promoting rapid growth.

3000 K – 3700 K

Produces a warm, yellow, neutral light. Used for promoting highly active photosynthesis during the growth stage.

1500 K – 3000 K

Produces a hot red or orange light. Ideal for promoting activity during the flowering stage.

Lighting at Different Stages of Growth

With this in mind, you might be thinking that you will require different grow lights for different stages of the plant’s life cycle, and for the best results and yields, you are correct. You do, of course, also need to consider the running costs of your lighting, because they can add up quickly.

HID and fluorescent lights are typically the most expensive to run at any wattage, so while they are often the lighting of choice for high yields, for smaller grow rooms, they can be remarkably impractical where costs are concerned.

LED lights, which are a far more developed and modern lighting technology, on the other hand, produce far less heat and consume much less electricity than just about any other type of grow light, making them ideal for cost-effective setups.

For Seedlings

Seedlings require little to no light at all, this is true whether they are placed in a growing medium or germinated from seed. 

Minimal light is required until the first leaves (cotyledons) show, and for indoor plants, you should avoid window light which will cause the seedlings to stretch. You want to keep those internodes short, so rather use low-wattage fluorescent or LEDs instead.

Avoid HIDs, even low-wattage ones, as they are far too strong for seedlings.

For Clones & Small Plants

At this stage you want to increase lighting while still keeping internode lengths short, so a high wattage fluorescent or a low wattage LED or HID is recommended here. 

This is also the case for clones that require a light source. 

For Vegetative & Mother Plants

Once about 4 leaves appear on the plant (not including the cotyledons) you can consider the plant to be in its growth stage, which means that it will need plenty of good quality light.

During this stage, high wattage HIDs and LEDs are your best bet for ensuring short internodal spacing and accelerated plant growth.

LEDs are a popular choice here because they are cheaper to run and produce much less heat, but veteran cultivators often opt for metal halide or high-pressure sodium HIDs for this stage.

Flowering Plants

Once the plant has matured to the point where it can flower, you will see that the calyxes (the portion in the nodes where the bud will grow from) have started to develop. 

Outdoor plants would generally wait for a change in seasons after this to start flowering, but indoor plants will change to the flowering stage when you manually reduce the hours of light it gets to 12 hours a day.

Indoor growers should consider what this means for changes to their grow lights. It is generally best to avoid fluorescents at this stage since they produce too many lumens and too much heat.

Because of this, high wattage LEDs and their gentler touch are far better, while experts often prefer to use high-pressure sodium HIDs at this stage.

Find the Right Grow Lighting at Skyline Grow Shop

Implementing the right grow lights for your needs doesn’t have to be complicated, although a little knowledge can go a long way towards producing the perfect yield every time.

Of course, you want to invest in grow light kits that you can rely on to perform dependably and give your plants the best they deserve. For great deals on quality light kits for grow rooms of all shapes and sizes, be sure to visit Skyline Grow Shop Instore or visit the Skyline Grow Shop online store today.