Do You Need Grow Lights for Hydroponics? The Surprising but Simple Trick to Know 

According to farmer John, “You’ll need grow lights for hydroponics if you want healthy plants all winter long.” 

Growing up on our farm, it was always a struggle when days grew short and sunshine was scarce. 

One cold year, I rigged some grow lights over my hydroponic basil plants just to see what would happen. 

To my surprise, the basil stayed bright green and healthy while others faded. With the right lighting, it seemed hydroponics could let us enjoy homegrown plants even in the depths of winter. 

Key Takeaway

  • Yes, you will need grow lights for hydroponics if your system does not receive a minimum of 2,000-3,000 lux of natural sunlight for at least 6-8 hours per day. This light level is difficult to achieve indoors even near windows.
  • You will also need grow lights anytime you want to grow plants through winter months or in cooler climates where sunlight hours and intensities are insufficient to support plant growth year-round.
  • Even with adequate sunlight, you may still need supplemental LED or fluorescent grow lights positioned strategically near plants to boost light levels for certain crops that require high photosynthetic photon flux densities like leafy greens, herbs, and microgreens.

Under What Conditions do You Need Grow Lights for Hydroponics?

do you need grow lights for hydroponics

Insufficient natural light

After years of growing plants indoors, I’ve found that hydroponic systems are often located in areas like basements or garages where natural light is greatly limited. 

Through trial and error, I learned plants require a minimum level of light energy called Photosynthetically Active Radiation (PAR) to fuel their growth and development.

Low indoor light levelsRisk of stretched, lanky growth as plants seek more light
Overcast outdoor conditionsPotential for inadequate radiation for photosynthesis
Shaded indoor areasThreat of stunted growth without sufficient illumination

Additional lighting may be necessary on gloomy days or in rooms without bright, direct sunlight penetrating multiple windows.

Controlling the light cycle

Precise control over the photoperiod proves extremely important according to my experiments. Many varieties demand a nightly dark respite to set blooms or set fruit. 

I’ve found grow bulbs empower matching native seasonal and circadian cycles. Adjusting light timing impacts flowering, ripening, and replication of environmental changes for continuous crops.

Growing plants all year round

Due to shorter days and sun exposure in fall and winter near our northern home, consistent lumens proved pivotal for my year-round indoor herb garden. 

As daylight dwindles, supplementing with lamps allows uninterrupted sustainability contrary to nature’s schedule. 

Perennial greens sprang up happily oblivious to the weather outside thanks to this photographic augmentation.

What Types of Grow Lights are Used for Hydroponics?

Fluorescent grow lights

After trying different lamp styles, I found fluorescent bulbs suitable for starting seedlings and low-light lovers. These include:

T5Thin tubular design for ample coverageGeneral illumination, ideal for herbal and leafy crops
T8Low cost yet sturdy optionSupplemental or auxiliary lighting
CFLCompact curly shape fits odd spotsMaternity wards for young sprouts

While economical, fluorescence yields weaker intensity over bigger footprints than other options.

LED grow lights

Through experimentation, LEDs have proven highly energy-efficient and long-lasting for full-cycle cultivation (1). Specifics include:

DiodesAdvantagesBest for
RedFlowering, budding, and fruitingFruits, blooms, and tomatoes
BlueVegetative developmentGreens, herbs, fast foliage
WhiteAll-round lightMulti-stage crops

Programmable spectrums and intensities suit all stages. Costs offset through electricity savings.

High-intensity discharge (HID) lights

For heavy harvesters demanding maximum PAR output according to my finds:

StyleTraitsPeak producers
Metal halideCrisp spectrumSeedlings, lowers, lettuce
High-pressure sodiumWarmer hueFruiters and mature plants

Output matches full sun but runs hot, warranting ventilation between bulbs and leaves. Best for fields than smaller areas.

How do You Determine Lighting Needs for Your Hydroponic System?

do you need grow lights for hydroponics

After frustrating seedling stretches early on, I learned each variety demands distinct daylighting. Here are the essentials:

Plant typeSensitivity to light levelsLettuce needs less PAR than tomatoes
Growth stageIntensity shifts as harvest nearsSeedlings need blue light; fruiters want red
SeasonSummer sunlight exceeds winter wattageBoost lumens in fall/winter
EnvironmentShaded spots call for supplementationWest-facing walls lack full spectrums

To assess adequacy, sensors such as PAR meters objectively measure illumination. Calculations account for system size too – more canopy consumes additional photons.

Proper lighting selection ensures optimal illumination (2). For instance, some LED arrays cater to young leaves while other full-cycle designs suit seasoning crops. Matching photosynthetic photon flux density ensures robust, rhythmic growth.

Judicious measurements and adjustments dialed my rig just right. Supplementing as seasons or circumstances change keeps producers picturesque.

Advanced Lighting Techniques for Hydroponics

After years of experimentation, I’ve refined my lighting practices for increased results. Some key strategies include:

Supplemental lighting

On overcast days, augmenting daylight with secondary sources like fluorescent tubes positioned beside shelves boosts productivity. Lower wattage lamps allow boosting illumination without scorching.

Beside plantsLocalized increasesSeedlings under shop lights
Above entire systemBroad supplemental lightLED bar above full hydro setup

Photoperiod manipulation

Timing of lumens impacts maturation according to my logs. Some bloomers favor:

Plant TypeDay Length TriggerEffects
Long day plants>12 hours lightStimulates flowering
Short day plants<12 hours lightInitiates budding cycle

Intensity stepping

Ramping wattage as foliage expands maximizes photosynthesis. Seedlings appreciate dimmer fluxes that stretchers can handle.

Spectrum mixing

Matching wavelengths to developments like stretching, blooming or fruiting keeps plants dynamically lit through all stages.

Careful consideration of techniques maximizes your harvests! Contact me for more garden illumination insights.


In summertime, my hydroponic plants thrive happily soaking in the sun’s generous rays. But as days shorten, growth lags without a little extra light to photosynthesize. 

Through various seasons of indoor gardening experience, I’ve observed how quality illumination makes all the difference. 

With a basic understanding of lighting needs, any backyard farmer can harvest hydro crops year-round by installing simple systems tailored to each variety. 

Feel free to share your own lighting victories and defeats in the comments – I’m always trying to learn! Together perhaps we can help others realize farming’s freedoms know no calendar.



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