Growing indoors? You need a plant grow light. Not just any grow light – one that’s built to British Safety Standards and suits your stage of growth.
There are so many lighting systems to choose from… where do you even start? Check out these frequently asked questions and our answers below.
Don’t forget, you can see complete lighting systems on display at all stores. Drop by and ask a friendly member of staff will help you find a great grow lights.
Questions and Answers
What’s a complete lighting system?
Complete lighting systems are made up of:
A ballast: To regulate how much power goes to your grow lamp
A reflector: To direct light emitted by your grow lamp down towards your plants
A grow lamp: To emit plant light, also call a grow bulb
What kind of grow light do I need?
There are 5 main grow lights. The one you need depends on your stage of growth and the results you’re trying to achieve.
Main HID grow lights (must during vegetative and flowering)
You will always need an HID (high intensity discharge) grow light.
The reason? They are the most efficient form of grow lighting, particularly HPS grow lights. They mostly emit wavelengths of light used by your plants for growth, which is wavelengths between 400 and 700nm (the PAR range).
From the PAR range, plants use blue wavelengths for vegetative growth and red wavelengths for flowering.
Some growers use a metal halide grow light during vegetative growth (emits mostly blue light) and an HPS grow light for flowering (emits mostly red light). However, this is a very old school way of growing. Life will be much, much easier if you simply use a dual spectrum grow light throughout.
Supplemental LEP (light emitting plasma) plant grow lights:
Light emitting plasma growing lights are designed to be used alongside your main HID grow light.
They mostly emit wavelengths of light from outside the PAR to bring your light spectrum a lot closer to natural sunlight.
They’re known to boost plant health while improving the size, quality, taste, aroma and appearance of fruit and flowers.
Supplemental CDM grow lights:
Most Ceramic Discharge Metal Halide (CDM) grow lights are also designed to be used alongside HPS lights.
They both broaden your light spectrum and boost your light intensity.
Though they don’t normally broaden your spectrum as much as LEP lights do, the fact that they also increase the amount of PAR light your plants get makes CDM grow lights a great choice for many growers.
How many grow lighting systems do I need?
The number of indoor grow lights you need depends on the size of your tent.
As a general guideline, here’s how much space you need for each grow light:
1 x 250W indoor grow lights per 0.75m x 0.75m area
- 1 x 400W indoor grow lights per 1m x 1m area
- 1 x 600W indoor grow lights per 1.2m x 1.2m area
- 1 x 1000W growing lights per 1.5m x 1.5m area
For advanced grow lighting systems, you’ll want a professional grow lighting layout. Visit your local store for advice on buying grow light systems and grow light kits.
When should I run my grow lights?
Your grow light on/off times are meant to mimic the seasonal conditions plants usually veg and flower in.
During vegetative growth, keep grow lights on for 18 hours and off for 6 hours.
During flowering, keep grow lights on for 12 hours and off for 12 hours.
To lower running costs, a lot of people have their growing lights on during the night and off during the day.
It works out cheaper because, on economy 7 tariffs, the cost of electricity is less during the night.
You also need to remember that growing lights produce heat. It costs less to maintain the right grow room temperature if you run your grow lights at night, when it’s cooler.
Can I change my growing cycle by changing my grow light on and off times?
Yes, you can.
To prolong vegetative growth, continue to run a Metal Halide grow lights or HPS Dual Spectrum growing light for 18hrs a day. You can also run the lights for longer; 20 hours on and 4 ours off. Some growers even run their lights for 24 hours a day.
To speed up flowering, run grow lights for 10hrs on, 10hrs off (using a Dimlux controller). Doing this will shorten your flowering cycle by 224 hours (just over 9 days!)
Do you sell grow light kits?
It depends on what you mean by a kit.
You can buy your lamps, reflectors or ballasts together as a complete system.
You can also get grow lights as part of a grow tent kit. If you’re a new grower, this is a great option. You’ll save money, and you’ll know that your light intensity and footprint will suit the shape and size of your tent.
Which ballast should I use?
There are two kinds of ballasts you can use with plant grow lights – magnetic ballasts and digital ballasts (aka. electronic).
Magnetic ballasts are fine, but you’re better off with a digital ballasts. They’ll prolong the life of your bulb, are cool running and completely silent. On top of this, they’re much cheaper to run and you won’t need to replace them as often.
What reflector should I use with my grow lamps?
The shape and size of your reflector determines the footprint of light you get.
When buying indoor grow lights, make sure your reflector suits the shape of your growing tent.
Grow lamps used with a Northstar reflector’s uniform, square footprint is ideal for centre of a square 1.2m x 1.2m tent (e.g. BAY6 XL tent)
Where should I position my grow lights?
It depends on your tent. Single lights can be placed in the centre of tents. The best thing to do is split your grow tent into sections, with one light in the centre of each section.
If you’re using an advanced plant growing lights, it’s a little more complex. If you have advanced Gavita growing lights, visit your local store for a free grow light layout.
Can I get away with cheap grow lights or will my yield suffer?
There’s no getting round it, you get what you pay for. Advanced lights are far better, but you can still get a really good yield using cheap grow lights.
Just make sure you buy them from a trusted, reputable seller.
Otherwise, you run the risk of buying badly made lights that use cheap parts and don’t even meet required standards. It’s just not worth the risk.