How many watts of LED do I need in a 1.2m area?

by Craig P

How many watts of LED do I need in a 1.2m area?

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With the most popular space for hobby growers being 1.2m x 1.2m tents, most large strip lights are now built specifically to cater to this area. The market has seen a recent explosion of these LED grow lights, creating what is now an over-abundance of choice for the consumer. While this is of course only a good thing, it can be difficult for most growers to make a choice about how much light is best for them. After all, more light isn’t necessarily better.

We’ve put together a guide to help with this issue based on the knowledge and experience we’ve gained over the years. As well as providing practical advice to hundreds of growers, we’ve carried out PAR mapping for every LED model that has passed through our hands, giving us a unique and data-driven perspective on what works best. It goes without saying that the best guide for any grower is their plants, and growers should always be focusing on what their plants are telling them when they make an adjustment to any input.

So now let’s go through the general wattage options (for flowering) and talk about what they mean for new and experienced growers alike. We’re specifically talking about LED grow lights that provide at least 2.4 micromoles of quality, usable light per watt/joule consumed (the vast majority of good LED grow lights) within the traditional PAR range:

400-500 watts (960-1,160 PPF)

This is the minimum wattage we’d recommend using in a 1.2m space. If you’re not scrogging wall-to-wall, are a new grower or have a mixture of plants, this is where you should be looking. LEDs produce brilliant levels of usable light, so fantastic results can still be had in 1.2 areas with these light levels. Many yield-focused growers that are new to LED make the mistake of throwing too much light at their plants too soon, however the wider margin for error provided by limiting light levels below a PPF of 1,160 means that you’re less likely to run into problems that could ruin the quality of your final product.

Example: PAR+ 465 Pro, Lumatek Zeus 465w Pro


500-600 watts (1,200-1,450 PPF)

For most personal growers with moderate growing experience, this is the range that we recommend for 1.2m spaces. With these light levels you’ll be able to get excellent results with only a low risk of over-saturation. Temperatures should also be manageable for all but the hottest climates, but we’d recommend hanging the light high and making full use of dimming capabilities until plants are established and in full swing.

Example: 2 x Telos 10 Pro (Slimline) bundleLumatek Zeus 600w Pro

600+ watts (1,440-1,740+ PPF)

Experienced growers who train for an even/level canopy and have a tight grip on their environment will be able to get exceptional results with these light levels, provided their plants are at peak metabolism via all other inputs. Large strip lights within this range will be able to provide 1000+ micromoles of light to the centre of the canopy at 12-16 inches and fantastic yields. If you’re new to LED growing and have just bought a light of this wattage for a 1.2m space, we would advise that you run the light below its maximum power setting for your first cycle.

Example: Scopex 680, Parlux Linx 650

We hope this rough guide helps growers to find the right light for them. If you’ve decided on an appropriate wattage for your space, bear in mind that not all manufacturers and sellers care about telling the truth (especially if doing so would reveal the inferiority of their own quality standards or materials) and growers can be led astray by performance falsification and exaggerated claims. We always recommend that growers choose from only the most reputable brands and apply a sceptical approach to performance claims that seem too good to be true.


Want even more light?

While we wouldn't recommend going above a PPF of 1800 for 1.2m spaces, elite growers using supplemental CO2 may be capable of pushing beyond this in the future as knowledge and techniques advance. Some growers may also feel the need to fluctuate between 1.2m-1.5m tent sizes, or to upgrade from 1.2m to 1.5m in the near future. If you're one of these growers who may feel the need for more light than the usual 600w strip lights offer, we'd recommend choosing a Scopex 900. With the ability to fully saturate 1.5m canopies - coming in at an eye watering 2120μmol/s - while still having the dimming functions needed to be utilised in 1.2m areas (not to mention the fantastic price and 5 year warranty), growers thinking seriously about long-term options should definitely consider this LED grow light.