How Many Watts Per Square Foot for Led Grow Lights

Each weed indoor grower knows that using best LED grow lights is essential for the plants’ proper and natural growth. For some growers, using LED grow lights comes with some questions, such as how many LED watts grow lights a square foot of indoor space needs.

However, the question does not have an exact answer to it. The watts of LED grow lights needed for each square foot depends on the following key factors.

How Many Watts Per Square Foot for Led Grow Lights

Bestseller No. 1
KOSCHEAL 2000W LED Grow Light Full Spectrum with Samsung LM301B and UV LEDs Daisy Chain Grow Lights for Indoor Plants Greenhouse Hydroponic Growing Lamps with Veg Bloom Switch Coverage 5x5ft
1,806 Reviews on Amazon
KOSCHEAL 2000W LED Grow Light Full Spectrum with Samsung LM301B and UV LEDs Daisy Chain Grow Lights for Indoor Plants Greenhouse Hydroponic Growing Lamps with Veg Bloom Switch Coverage 5x5ft
  • 👍HIGH EFFICIENCY LED GROW LIGHTS: KOSCHEAL LED plant grow light has adopted the newest LM301B diodes and the newest SMD LED technology provides the highest PAR/LUMEN output, high energy efficiency with 2.8umol/J while speeding up photosynthesis, designed to replace a single-ended 400watt HPS/CMH grow lights!
  • 👍UPGRADED COMMERCIAL LED GROW LIGHT: Daisy chain compatible to make fewer cords, which can connect with other grow lights to extend the coverage. No more than 3pcs growing lamps can be connected and used together by power cords. Energy & money & time- saving. The power supply works on 90VAC to 277VAC, suit for large rooms and commercial Setups. Perfect for 4’x4’ vegetative coverage and 3.5’x3.5’ flowering coverage.
  • 👍FULL SPECTRUM LED GROW LIGHT: According to the light compensation point and saturation point of the plant(MJ),the more suitable spectrum of the plant(MJ) was proportioned.Total 596 LEDs included 460nm,620nm,730nm(IR) and 396nm(UV) which can replace natural sunlight. UV diodes stimulate anthocyanins,which improve the quality of fruits and flowers.
  • 👍SAFE&DURABLE LED GROW LIGHT: Without the design of the reflector because the led reflector is not heat-resistant. If a short circuit occurs, the reflector is easy to melt and fire. We adopted cooling fans design of high speed &super quiet & upgraded aluminum cooling heat sinks so that the heat dissipation efficiency is improved and the light decay is slowed down. Save the cost of changing lights frequently.
  • 👍WORRY-FREE PURCHASE: We promise 30 days money-back guarantee and US local after service for 3 years. We will reply within 24 hours for you. If you have any questions, please feel free to contact us.THX!
Bestseller No. 2
Giixer 1000W LED Grow Light, Dual Switch & Dual Chips Full Spectrum LED Grow Light Hydroponic Indoor Plants Veg and Flower-1000 watt ( 10W LEDs 100Pcs)
4,808 Reviews on Amazon
Giixer 1000W LED Grow Light, Dual Switch & Dual Chips Full Spectrum LED Grow Light Hydroponic Indoor Plants Veg and Flower-1000 watt ( 10W LEDs 100Pcs)
  • New Upgrades: Compare with the traditional 1000 watt grow lamps, this new Dual-Chips 10w led lights is bigger, brighter and efficient, but consuming only 110 watts.
  • Perfectly help you to save the energy and improve the environment of plant growing. DOUBLE SWITCH- Veg and Bloom button have different function. Veg switch: It's blue led and white led. For seeding or young vegetative growth,you can use Veg switch only. Bloom switch: It's red led and white led.for flowering/blooming,you can use both Veg and Bloom switches.
  • Most LED lights are rated at somewhere 50000 hours of use. For comparison, many other grow lights tend to last for around 20,000 hours before needing to be replaced.Protecting diodes are added to make sure one chip out, others still work.
  • Full spectrum: the light include red,blue,yellow,white,and so on etc. which is similar to the sunshine,ideal for all kinds of indoor plants veg and flower at all growth stages.
  • 【Warranty and Customer Service】24 monthes quality guarantee and 30 days refund
-$7.00 SALE OFFBestseller No. 3
75W LED Grow Light for Indoor Plants Growing Lamp 225 LEDs UV IR Red Blue Full Spectrum Plant Lights Bulb Panel for Hydroponics Greenhouse Seedling Veg and Flower by Venoya
2,112 Reviews on Amazon
75W LED Grow Light for Indoor Plants Growing Lamp 225 LEDs UV IR Red Blue Full Spectrum Plant Lights Bulb Panel for Hydroponics Greenhouse Seedling Veg and Flower by Venoya
  • ❤️ FULL SPECTRUM: 225 high quality super bright LEDs with spectrum 390nm-730nm, including UV IR Red Blue. Plants can get the spectrum they most desire from this grow light and it’s suitable for all stages of growth such as seeding, germination, vegetative & flowering.
  • ❤️ WIDE APPLICATIONS: Widely used for grow tent, grow box, grow chamber, grow room, hydroponics, aquaponics, greenhouse, vertical farm, indoor gardening and so on. It is suitable for almost all the plants, such as herbs, succulents, vegetables, bonsai tree, houseplant, orchid, lemon, chili, tomatoes, algae etc.
  • ❤️ ENERGY-SAVING: Upgraded to Max. LED Power 75W, Avg. Power Draw 27W, replace 100W HPS or HID grow light with only 27W consumption. Good for 2’x2’ growing space.
  • ❤️ USER FRIENDLY: ABS material in square shape with air-flowing construction, excellent cooling capacity with no fans no noise. Easy set-up, whole plant light can be assembled by hands, no need extra tools.
  • ❤️ WORRY-FREE WARRANTY: 12 months warranty plus 30 days satisfaction or return guarantee, 100% money back. Contact us first if any issues and we will make it OK. Pursuit of your satisfaction is always our Target!
Bestseller No. 4
Juhefa LED Grow Lights, Full Spectrum Grow Lamp with IR & UV LED Plant Lights for Indoor Plants,Micro Greens,Clones,Succulents,Seedlings,Panel Size 12x4.7 inch
7,978 Reviews on Amazon
Juhefa LED Grow Lights, Full Spectrum Grow Lamp with IR & UV LED Plant Lights for Indoor Plants,Micro Greens,Clones,Succulents,Seedlings,Panel Size 12x4.7 inch
  • Full Spectrum Growth Lights - equipped with 75 High-power LED chips: 47Red/19Blue/3UV/3IR/3White. NOTE:The UV & IR LEDs are particularly DIM, but it is normal. PANEL SIZE: 12.2x4.7x1.2 inch.
  • Highly Efficient LED Lamp - as for LED power draw this seedling light is highly efficient. Estimately monthly cost roughly $3 in electricity (12 hours a day). It is a great option for plants that in seedling, vegetative and flowering cycle.
  • Compact Size & Wide Uses - the best gift for gardening and planting enthusiast. Mainly used for small plants, mirco-greens, peppermint, herbs, african violets, tomatoes, potted plants. And perfect for you to add as a supplemental side panel during bloom.
  • Easy Set Up - adjustable hanging light kits make this fluorescent lights much more easy to assemble. With good heat dissipation and strength ABS material body ensures your panel more durable and long-lasting.
  • What Will You Get - we take pride in delivering top quality products and offering our friendly 12 Months Warranty plus 30 Days Money Back Guarantee for any reason. You can contact our 24 hours available customer service through clicking "Sold by" on the product detail page or your Amazon order page and you will be directed to "Ask a question" to send us message.
Bestseller No. 5
LED Grow Lights, WY CN P1000 Upgraded Full Spectrum Dual Chip Grow Light with Daisy Chain Design for Hydroponic Indoor Plants, Seeding, Flowering Fruiting Grow Lights for Indoor Plants
296 Reviews on Amazon
LED Grow Lights, WY CN P1000 Upgraded Full Spectrum Dual Chip Grow Light with Daisy Chain Design for Hydroponic Indoor Plants, Seeding, Flowering Fruiting Grow Lights for Indoor Plants
  • [High Power Double Chips Design] Design with 100pcs 10watt super bright double chips LEDs, 90/120 degree mixed LED angle, higher PAR/Lumen output per watt than others, better for hydroponics greenhouse aquatic indoor plants growing, maximize growth.
  • [Daisy Chain Available] - The plant light with daisy chain design allows multiple lights to connect in parallel at the same time. If using the typical 110V AC supply, each light draws 1.6A. To ensure safety, not more than 5 lights together per chain.
  • [Energy Saving 80% Than HPS/MH] Save your money a lot! WY CN 1000W LEDs plant light for indoor plants for planting can replace traditional 1000 watt HPS/ MH while consuming only 80W ± 3%! Perfect for a 4.5x5ft growing area at 24" height.
  • [Wide Application] The plant grow light can be used for water-soluble culture and soil culture, suitable for all indoor growth environments, such as growth tents, growth rooms, greenhouses and indoor gardens. Please pay attention to the growth pattern of the plant, adjust the height and use time to meet the needs of the plant.
  • [Professional Customer Support] 24 Months warranty and friendly customer service and 90 days money back guarantee,Each of Our led grow lights for indoor plants full spectrum has passed strict inspection before they leave the factory.If there is any problem or you are not satisfied 100%,please feel free to contact us by contact way on the product at once. Enjoy this absolutely RISK FREE purchase by clicking the yellow Add to Cart button.

Factors To Take Into Consideration When Choosing Watts Per Square Foot For LED Grow Lights

The following factors lay the largest role in determining the watts per square foot for the LED Grow lights.

Nature Of Your Crops

The type of crops you choose to grow in your indoor space will determine the light needs. Led grow lights come with varying watt power, and come crops require LED grow lights specially designed for them.

You may find that some grow lights will do only well with crops such as succulents, herbs, vegetables, and other small plants only. You will also get lights that are good for the same plants but do not come with any limits. Other factors to consider on the nature of the crops are as follows.

Plant type

Some plants such as weed, tomatoes, and pepper, require high light intensity while many others, such as herbs, thrive well with average to low light intensity. In this case, if you are growing plants that need more light than others do, you will need lights with more wattage.

Stage of growth

Each plant’s growth process goes through several phases, starting from seedling to germination, vegetative, and flowering. Each of the phases requires different light intensities. For example, during germination, plants require little or no light at all.

However, as the plant continues to grow, the need for light intensifies, as seen during the vegetative and flowering phases. The flowering phase needs light, but the same stage also needs to go through more darkness hours. The light requirement during this stage helps with the production of larger buds.

The numbers of plants you have in the indoor grow space

How many plants are you growing in your indoor space? If you have a high number of crops, you will need to increase the light intensity to allow each of the plants to get enough light.

Grow Tent Size

Grow tent size is another factor to take seriously if you are to determine the LED grow watts. If you have a large grow tent, you will require a higher light intensity than you would with a smaller one.

LED Grow Lights Type

Besides having different watt levels, LED grow lights also come in varying other factors. LED grow lights differ in their heights, color spectrums, and heat outputs. You can use the same watts on plants and yield different harvests.

  • Color spectrums

If you want the best growth for your crops, you have a mixture of colors from your LED grow lights. Using one color spectrum such may provide you with plants that come with one deformity or another.

White color LED grow lights mimic the sun’s natural light, which is great for the crops, but it comes with yellow and green lights that do not provide any benefits without other light spectrums.

Adding red, blue, UV, and IR lights guarantee a healthier plant. This makes multi-colored or full-spectrum LED grow lights a favorite with a good number of weed growers.

  • LED grow light height

Height or distance between the plant and the LED grow light also determines the amount of wattage you need for the grow space each time you change the grow light’s height, the crops receive different amounts of light intensity.

  • Heat Output

Heat output is another important factor to consider when determining How Many Watts Per Square Foot for Led Grow Lights you need in your grow tent.

Even though LED grow lights produce the same amounts of heat during operation, you get the best results from low heat output grow lights. You can only get low heat output from grow lights that come with heat-reducing features to prevent overheating.

So, How Many Watts Per Square Foot for Led Grow Lights?

Square FtFootWatts
40(6×7)1280
36(6×6)1150
30(5×6)960
25(5×5)800
20(4×5)640
16(4×4)500
12(3×4)400
9(3×3)300
6(2×3)200
4(2×2)120
2(2×1)60

After considering all the above factors, we can answer the above question. To determine the wattage, your indoor space needs per square meter, measure the grow tent width and multiply it by the length, then buy lights with the intensity to match the space.

How Far Should Led Grow Lights Be From Plants

Cannabis plants require lots of light to grow big buds, but you need to increase the light levels depending on growth stages. When creating the height difference, you also have to bear in mind that lights come with different brightness and heat output levels depending on the brand.

Unlike other grow lights such as the HPS OR MH, it is not easy to determine the distance needed between LED grow lights and the plants. For the best distance, you should consult the manufacturer of the LED grow light. However, the chart below is the closest to the height LED grow lights need to be from the plants.

WattageDistance Between LED Grow Light And Top Of The Plant (Inches)
200-399

12-20

400-599

20-27

600-799

30-38

800-999

32-42

1000 Plus

36-46

Wrapping it up

LED grow lights are the best lights to use for marijuana indoor growing. Unlike many other lighting systems, the lights provide the crops with better wattage per square foot without harming the crops from too much brightness or harmful chemicals.

Lights provide the crops with better wattage per square foot without harming the crops from too much brightness or harmful chemicals. They also come with modern full-spectrum lighting panels and last longer.

With the above details, you can choose the correct wattage for your indoor space.

Bestseller No. 1
LEOTER Grow Light for Indoor Plants - Upgraded Version 80 LED Lamps with Full Spectrum & Red Blue Spectrum, 3/9/12H Timer, 10 Dimmable Level, Adjustable Gooseneck,3 Switch Modes
10,520 Reviews on Amazon
LEOTER Grow Light for Indoor Plants - Upgraded Version 80 LED Lamps with Full Spectrum & Red Blue Spectrum, 3/9/12H Timer, 10 Dimmable Level, Adjustable Gooseneck,3 Switch Modes
  • Efficient LED Combination: This LED lamp has grow lights made up of 80 efficient growing LEDs (36 red, 16 blue and 28 full spectrum). It meets the conditions of plant growth without sunlight. 1--Full Spectrum(380nm-800nm): Suitable for all plants to root and sprout. 2--Red(660nm)+BLUE(460nm) Spectrum: for blooming and fruits. 3--Red+Blue+Full Spectrum: A mix of Red+Blue+Warm White is best to fuel the growth of your plants.
  • Upgraded Auto ON/OFF Timer: Plant grow lights come with the circular memory timer function allows to automatically turn on/off every day according to your settings: 3H(Blue)/9H(Green)/12H(Red). Which requires no manual operation and takes good care of your plants when you on work or vacation.(Please note: The timer needs to be reset if the grow light is powered off.)
  • 10 DimmableModes: Our grow lamps provides 10 dimmable modes to suit varied stages of plant growth. It has 10 levels of light intensity and has 3 spectral modes to meet different stages of plant-growing needs.
  • Visible Quality and Adjustable: The LED grow lights have a USB connector which makes it convenient to connect in your office or home to USB or AC power plug (includes adapter). The 4-head light has a 360-degree flexible gooseneck made from quality tubing to keep a fixed position. The metal clamp allows the lamp to be placed anywhere in your home or office.
  • Scientific Heat Dissipation Design: Indoor LED grow light is backed by an aviation-grade heat sink powered by a temperature control unit. This improved heat sink efficiently dissipates the heat generated by the lamp to the atmosphere.
-$15.50 SALE OFFBestseller No. 2
GooingTop LED Grow Light,6000K Full Spectrum Clip Plant Growing Lamp with White Red LEDs for Indoor Plants,5-Level Dimmable,Auto On Off Timing 4 8 12Hrs
9,500 Reviews on Amazon
GooingTop LED Grow Light,6000K Full Spectrum Clip Plant Growing Lamp with White Red LEDs for Indoor Plants,5-Level Dimmable,Auto On Off Timing 4 8 12Hrs
  • 【6000K White Light】Equipped with 10 Red + 74 White LEDs, this mini growing light is similar to the full-spectrum sunlight at noon,that is professionally designed for indoor garden plants.Moreover, its color rendering index is as high as 95, the light is soft and flicker-free, which is very suitable for reading lamp
  • 【Timer Function & Multiple Settings】The indoor seedling light offer the circular memory timer function with 3 options-4h/8h/12h. When keeping power, it can automatically turn on and off every day according your settings, no more manual operation for you.【Also You Could Operate One of Them Separately,And Support 5 Levels of Dimming.】
  • 【Easy to Install】with flexible Gooseneck & strong clamp,it allows you to place the LED plant lighting fixture in any direction to provide the best lighting angle for your plants,meet the cover around the plant.Powered by USB or AC Power Plug (adapter included )
  • 【High Efficiency LED Lamp】as for LED power draw this mini succulent lights just comsume about 10watt and is equivalent to a 50w halogen bulb.Estimately monthly cost roughly $2 in electricity (12 hours a day). It is a great gift if you growing some desktop small plants.
  • 【365 Days Worry-free Warranty】We offer 365 days warranty and 24h friendly customer service. If there are ever any issues about the product, please feel free to contact us and we will give you a free replacement or full refund.
Bestseller No. 3
Grow Lights for Indoor Plants, Romsto LED Full Spectrum Plant Light for Indoor Plants, Height Adjustable Grow Light with 10 Dimmable Brightness, 8/12/16H On/Off Timer, Ideal for Small Plants, 2 Packs
1,041 Reviews on Amazon
Grow Lights for Indoor Plants, Romsto LED Full Spectrum Plant Light for Indoor Plants, Height Adjustable Grow Light with 10 Dimmable Brightness, 8/12/16H On/Off Timer, Ideal for Small Plants, 2 Packs
  • 【2 in 1 Home Garden Lighting Design】: Not only a grow light, but also home decor, this grow light is perfect for placing it at spaces like office desk, living room, dark corner in your house. This plant light is designed like a halo, mimicking natural sunlight, helps plants to grow faster and healthier. The warm natural light is eye-friendly and ideal for home and indoor use, perfectly fits in with home decor.
  • 【Full Spectrum & 10 Dimming Levels】: This grow light applies the full spectrum LED chips, emits wavelengths from 380nmup to 800nm- just like natural sunlight. It can be more effective in accelerating photosynthesis and plant growth at all stages. And this plant light has 10 brightness settings ranging from 10% to 100%, you can choose the brightness your plants need at different stages, to help plants grow faster and better.
  • 【8/12/16 Timer & Auto On/Off】: This grow lights for indoor plants is equipped with a built-in timer of 3 modes cycle timing settings - stay on for 8/12/16 hours, then off for 16/12/8 hours. And it will automatically turn on and off at the same time the next day, no need to unplug or re-plug. It will take good care of your plants everyday, no need to worry about your plant while you are not at home for a long time.
  • 【Easy to Install & Height Adjustable】: Just stick it in potted plant, adjust height and angle, then turn it on. 1-step installation, quick and easy! This plant light for indoor plants has a telescopic pole (6.5-24 inches), can be retracted up and down. You can adjust the reasonable height for the plant growth, and a large area or more plants will be covered when the pole is extended longer.
  • 【Widely Used & Housewarming Gift】: The feature of sticking into the soil or planter, this grow light is very versatile and applicable for all types of locations, such as hanging, trellis, floor planters and so on. As a stylish decoration for any home space, this plant light is a unique housewarming gift, perfect for gardeners and plant lovers to look care of plants and vegetables.
-$5.00 SALE OFFBestseller No. 4
Grow Light, LORDEM Full Spectrum LED Plant Light for Indoor Plants, Height Adjustable Growing Lamp with Auto On/Off Timer 4/8/12H , 4 Dimmable Brightness, Ideal for Small Plants, Pack of 2
3,040 Reviews on Amazon
Grow Light, LORDEM Full Spectrum LED Plant Light for Indoor Plants, Height Adjustable Growing Lamp with Auto On/Off Timer 4/8/12H , 4 Dimmable Brightness, Ideal for Small Plants, Pack of 2
  • Unique Artistic Design: The set of 2 plant lights are carefully designed like a halo for your plants to help them grow better and faster. They are not only plant lights, but also a stylish decoration for any home space, The warm natural light makes them very comfortable to see and to place in your home, they perfectly fit in with your home decor.
  • Full Spectrum Grow Light: It emits all the wavelengths from 380nm to 800nm- just like natural sunlight. With the warm white high efficiency LED diodes & higher PAR output, the grow light greatly promotes indoor growth as it accelerates photosynthesis, ideal for all stages of growth and various of plants such as herbs, succulent, orchids, tomatoes, etc. SAVE YOUR DARK INDOOR PLANTS with IT ! (50,000 hours lifetime.)
  • Auto on/off Timer Everyday: This growing light has 3 cycle timing settings (4/8/12H) which will stay on for 4/8/12 hours, then off for 20/16/12 hours and will automatically turn on and off at the same time the next day, no need to unplug/re-plug. It will take good care of your plants while you are at work or on vacation, easy & convenient!
  • Brighter Plant Light with 4 Dimmable Levels: Our grow light has more new technology LED diodes which makes it brighter and more efficient. Also it has 4 brightness settings (25%-50%-75%-100%), to meet each plant's lighting requirements at different stages, without worrying about burning your plant.
  • Easy to Use & Height Adjustable: Just stick it into potted plants, adjust height, then turn it on, quick and easy! The lighting part can be adjusted in height in order to work with different plants and provide the right amount of light intensity for each plant. Also a larger area or more plants will be covered when the telescope is extended longer.
-$4.20 SALE OFFBestseller No. 5
Grow Lights for Indoor Plants, DICCEAO 150W LEDs Grow Light for Seed Starting with Full Spectrum, 3/9/12H Timer, 10 Dimmable Levels, 3 Switch Modes
1,568 Reviews on Amazon
Grow Lights for Indoor Plants, DICCEAO 150W LEDs Grow Light for Seed Starting with Full Spectrum, 3/9/12H Timer, 10 Dimmable Levels, 3 Switch Modes
  • 5 Head 150 LEDs Plant Light for Indoor Plants: This plant growing lamp consists of 150 effective growing LEDs, divided into 120 white LEDs and 30 red LEDs. The 5 heads grow light for indoor plants supplies a broader lighting range than the traditional 2, 3, and 4 heads indoor plants lights, and increases the intensity of the light by up to 50%, allowing your plants to receive better and extra light energy.
  • 3 Spectrum Modes & 10 Brightness Levels: The full spectrum led grow light has 3 spectrum modes, which are Red, Full, and Mixed Spectrum. It has ten brightness settings, starting from 10% to 100%, that can be switched as per your requirements, so you are able to choose the more proper spectrum and brightness for your plant to grow in the best way. The indoor plant lights make your plants develop a rapid response to grow, five times faster than plants with natural light only.
  • Auto Timer Function & On/Off Cycle: Designed with a function for autocycle memory timing, there are different three timer settings for you to choose from, between 3H, 9H, and 12H of lighting time. Following your setting, the plant grow light will switch on/off automatically every day. Even when you are away from home, these grow light lamps will take good care of your plants every day.
  • Flexible Gooseneck Neck & Strong Clip: You can place and clamp the 5 head grow light anywhere as it has a strong clip and bracket support for it to be stable. The indoor grow lights have a 360 rotation design that can be independently adjustable, so each can be rotated to any angle to adapt to your requirements, which supplies a wider and more flexible range of light, and different growing directions.
  • Designed for Indoor Plants to Growth: These plant lights for indoor growing is perfect for the different sunlight needs of your plants depending on their growing stage, from seeds to every growing phase. The lamps have an excellent performance of fast heat dissipation, which ensures that these lamps provide you with a long-lasting and durable service life of up to 80,000 hours.
5/5 - (2 votes)

Bowden draws from over a decade of home growing experience as well as consulting for small-scale and hobbyist-level growers. He has written hundreds of articles, thought pieces, and tutorials about growing cannabis at home

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