Setting Up Your Cannabis Grow Lights

Setting Up Your Grow Lights – An Expert Guide

how to set up cannabis grow lights

If you’re growing marijuana plants indoors, it’s important to be aware that too much light can cause just as much damage to your growing crop as not enough light. In this expert guide, you’ll find out all you need to know about how to set up your grow lights so you can maximize your indoor harvest.

Which Grow Light Is Right For Me?

There are three popular types of artificial grow lights that you can choose for your indoor setup: LEDs, CFLs, and HIDs. Of those three, light-emitting diode lights (or LEDs) are the most modern and are rapidly becoming the lamp of choice for growers everywhere.

As a general rule:

HID lights are ideal for auto-flowering strains because they are potent and allow for faster growth.
LED lights are best for feminized strains and fern strains due to their low energetic waste and the slower rate of growth that they allow.
CFL lights are best for use in small spaces due to the lower level of heat which they provide which enables the lights to be placed nearer to the plant canopy. They are also ideal for seedlings and micro growing.

How Much Light Do I Need?

In general, 400W to 600W per meter squared is the best option for growing at home. Don’t fall into the trap of putting too many lamps into your growing space. This won’t mean a bigger harvest and will also increase the heat substantially. If you’re a micro-grower, 250W lamps may be suitable, but for a bigger crop, they won’t allow the light to reach taller plants’ lower branches.

If you can afford a full LED setup, you’ll find that high-performance kits such as those from Plantslily draw only 350W – 400W but can still outperform 600W MH bulb. These systems also run cool for extra economy in the long-run.

In order to determine how much light your crop is going to need, there is a simple formula you can use:

Multiply the length of your grow space by its width. This will give you the figure for your growing surface. You then multiply the figure you’ve obtained with the desired PPFD level.

How Many Plants Am I Able To Grow?

Here is a rough guide to the number of plants which can be grown depending on the size of your grow space and the wattage of your lamps:

HPS lights can cover approximately the following areas:

250 watts – up to 1 square meter – 2 plants

400 watts – 1 to 1.5 square meters – 4 plants

600 watts – 1.3 to 2 square meters – 8 plants

1000 watts – 1.8 to 3 square meters – 10 plants

LED lights are able to cover approximately the following areas:

120 watts – 0.5 meters squared – 1 plant

200 watts – 0.8 meters squared – 2 plants

280 watts – 1 meter squared – 4 plants

350 watts – 1.5 meters squared – 6 to 8 plants

How Far Away Do The Lights Need To Be From The Plants?

HID bulbs have both HPS (high-pressure sodium) versions for the flowering stage and MH (metal halide) versions for the vegetative stage. These lights run hot and therefore require a suitable cooling system. They also need to be placed further from the plants to avoid burning. The best distance for HPS and MH bulbs will depend on their wattage. With suitable ventilation and a small 250W bulb, a distance of 35cm from the canopy is a good place to start, progressing to 25cm from the buds when the flowering stage is coming to an end. With a 600 watt bulb, a distance of 50cm from the canopy descending to 30cm should be ideal while an 80cm distance is best for a 1000 watt lamp.

Although LED lights are cooler running than HID lights, they still require some cooling to guard against accidental damage to the plants. All LED lights have different instructions regarding distance from the plant canopy, so make sure to check them before setting up your grow system. As a rule of thumb, begin at a mid-distance in the recommended distance range and watch your plants closely for a few days. If the leaves begin to look burned on the tips or turn pale, move the lights further away. If they seem fine, you can move the panel a little closer but never so far that the leaves begin to yellow, turn brown or bleach.

An LED panel of over 300W must be maintained at a distance of 70cm at least from the canopy until the flowering stage when it can be moved closer. In general, LED lights of 200-400W need to be positioned at 30-70cm from the plants while lights of 450-600w need the distance to be 50-80cm.

Getting Your Grow Lights Right – Top Tips

Follow these expert tips and you’ll find that your grow lights are in the perfect position to maximize your crop and to ensure the best quality plants. Although it isn’t always easy to set up the ideal grow light setup, this advice should help you to achieve success the first time.