What Size LED Grow Light do I need?

If the term LED grow light is relatively new to an amateur gardening enthusiast or a weed entrepreneur, then this is a perfect article which sheds light on the cardinal question “What Size LED Grow Light do I need?”

LED grow lights are different from the traditional forms of grow lights used conventionally from time immemorial. Grow lights that fall under the metal halide category, or the high-pressure sodium lamps are entirely different both in shape, size, operating temperatures, construction and of course lumen value from that of their LED counterparts.

Apart from the features above, a LED grow light also differs from their traditional counterparts in terms of spectral range, power, wattage, and heat load. It is convenient for the plant as well as the entrepreneur to invest some time to gather knowledge on what would be the best possible choice of LED growing light for their DIY project on horticulture.

The size of a grow light depends on the following:

  1. The type of plant you are growing
  2. The available growing space
  3. The LED grow light type

What is the kind of plant you are growing?

Before anyone makes up their mind and takes a final decision on a particular type of grow light, it is of crucial importance that the nature and species of the plant are taken into careful consideration.

It should be kept in mind that all LED grow lights available in the market are capable of assisting a seedling in reaching full maturity, but some crops need more than that. Some specific types of LED grow lights are also available in the market that is precision engineered to cater to the particular needs of the unique plant species.

The available grow space size

The total area you devote to your indoor plants garden depends on the number of units of LED grow lights a person needs to fulfill the demands of the traffic. It is recommended to use at least 33 watts of LED grow to light per square foot of the growing area.

To illustrate further, take into consideration a scenario where the growing space is confined to a mere 16 feet, then the required LED grow lighting equipment should have a wattage of about 500 – 550 watts. The plant in question and recommended to be put under such immense light should be a plant that needs to bloom and open up the petals in its flower. Growing vegetables and fruits requires half of the above mentioned amount of LED light.

If the species that you are growing belong to the shrubs and herbs that use and need the very low amount of light like lettuce then the recommended amount of LED growing light needs to be within the 11 – 18 watts range, with a perfect balance between DLI and PPFD especially for big, leafy plants.

Given below is a reference chart that clearly enunciates the LED growing light wattage essential for a particular amount of available growing space (expressed in feet).

Note: 1 sqft grow space = 32 watts LED grow light

Space Watts
2 sq ft (2×1) 64
4 sq ft (2×2) 128
6 sq ft (2×3) 192
9 sq ft (3×3) 288
12 sq ft (3×4) 384
16 sq ft (4×4) 512
20 sq ft (4×5) 640
25 sq ft (5×5) 800
30 sq ft (5×6) 960
36 sq ft (6×6) 1152
40 sq ft (6×7) 1280

The information listed above is obtained from tried and tested results in terms of both yield, resin content and overall quality of life of sample plants (both vegetative and flowering).

If a person is considering of growing vegetables, then he/she should consider reducing the intensity of the light source by 50%. In other words, it is always better to follow the instruction of experts and try to consult with and heed an expert’s opinion before installing LED growing lights in your growing space.]

The Type of LED grow light

The wattage of the LED growing light apparatus mainly depends on the type of plants you have chosen for your hobby/business venture. If you want to let your seedlings sprout from its dormant to a fully developed flowering plant, it is advised to go for a full cycle LED grow lighting equipment.

Plants that need to absorb high amounts of intense light for their overall structural and functional development needs to be coupled with single channel LED grow lighting systems.

Programmable LED grow lighting systems are by far, the most advanced of the all current systems available in the market. It is especially preferred since these LED panels are equipped with one-touch control options that assist the user to skip the complexities of manually inputting all the variable of the light output during each phase of the plant’s life.

For effortless grow, most of the programmable LED lighting systems are equipped with hardware and firmware that ensure an effortless grow for the plant.

Watts per square foot

An average LED grow light is capable of consuming about 32 watts of electrical energy for illuminating 1 square foot area in the growing room, in case of flowering plants.

While on the other hand, a traditional grow light apparatus, for example, the humble HID fixture will be consuming almost 44 watts of electricity for illuminating the same amount of grow area.

The statistics and math clearly point out that LED grow lights are far more efficient and pocket-friendly when compared to that of the traditional form of grow lighting apparatus.


To sum it all up, the type of LED grow light depends on several factors that include your budget, the plant type, the available growing space, annual or monthly expense and cost of maintenance.

If an individual maintains the data and information stated in the above sections, then it is evident that their yield, the resin content and the quality of the plants will improve from before when the traditional forms of grow lights were being used.

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