How Many LED Grow Lights Do I Need for 12 Plants?

We have received a lot of emails from our customers recently, and many of them asked us a question: If I want to grow 12 plants, how many LED grow lights do I need to buy?

Well, that's a really good question. But before answering this question, we need to understand a few concepts. For example, what size growing pot do you use? How big is your grow space/grow tent? And LED lighting coverage area.

grow indoors

We conducted a customer survey and found that many customers prefer to use 5 gallon buckets and 4x4 grow tents when the plants are vegetative. So let's take these as examples.

Grow Pot And Grow Area

As seedlings require the least amount of light, you can use a low-power lamp such as a T5 during this stage. However, after the seeds have germinated for about 8 weeks, you can start transplanting the plants.

seeds sprout

There are some growers who prefer going from a 1-gallon to a 2-gallon to a 5-gallon container. And there are also growers who transplant directly from 1-gallon to 5-gallon to avoid too many transplants which might harm the plants.

You should be careful not to water all 5 gallons of soil at once, just around the stem of the plant where the young roots are, since newly transplanted plants are still relatively small and fragile.

The diameter of a 5-gallon bucket is 12 feet, or 30 centimeters. A 4x4 ft grow tent is 120cm long and 120cm wide. So if it's a 4x4 tent, you can put four 5-gallon pots. If you need to grow more plants, 6 at most during the vegetative period, as you need to ensure regular watering of the plants, a space for feeding the plants, and airflow in the growing environment.


5 gallon pot size

However, during the flowering stage, you can only put up to four pots of plants, as the plants themselves continue to grow and buds develop. The size and volume of the plants will increase. Plants need a lot of space for root development.

LED Grow Light Coverage Area

To grow light-demanding plants, you need 30 to 40 watts per square foot of canopy area. A 600-watt LED grow light can cover a 5x5 tent during the vegetative period, but can only cover a 4x4 tent during the flowering period. So, if you are using a 4x4 grow tent, you can consider reducing the wattage by 50% during the vegetative period of the plant, because growing in vegetative only requires about half the light intensity.

12 plants are best configured with three 4x4 tents. Then hang a roughly 600-watt LED grow light in each grow tent.

five 5-gallon in grow room

If you grow a lot of plants and your space is larger, you can figure out that number as above calculations. 16 square feet(4x4ft) uses 600 watts LED grow lights to 4-6 plants.

Finally, you need to know that for the best harvest results, plants need to get around 300 to 600 umol/m²/s in the vegetative stage and 600 to 1000 umol/m²/s in the flowering stage. These are the minimum requirements, if gets lower than these numbers, plants will become unproductive.