How long should hydroponic light be on?

Author: Margarete Hoppe  |  Last update: Monday, May 5, 2025

The light timing of a hydroponic light depends largely on the growth stage of the plant. Seedling stage: 16-18 hours of light per day is needed to support rapid growth and development. Vegetative stage: 16-18 hours of light per day is needed to promote strong, healthy growth.

How long to leave hydroponic lights on?

The duration you can leave a grow light on a plant varies based on factors. As a general guideline, you can leave the grow lights on for 8 to 16 hours per day during the vegetative stage. However, never leave your plants under the grow lights for more than 18 hours.

Can hydroponic plants get too much light?

Plants are highly dependent on light for their growth and development, as it is essential for the process of photosynthesis. However, both too much and too little light can lead to light stress in plants, which can have detrimental effects on their growth and productivity.

Should I leave my grow light on 24/7?

Is There A Limit To How Long You Can Leave Lights On? Short answer: yes. Even long-day plants need a daily respiration period of at least 6 hours (for seedlings) and ideally 8-10 hours for mature plants. We do not recommend providing more than 14-16 hours of light per day, even for long-day varieties.

Do hydroponic lights use a lot of electricity?

The grow light wattage required to delivery a good yield will range from 400 to 650 watts, depending on the technology used. Therefore the power consumed by your grow light is about 80-90% of the total used in the grow room (excluding air conditioning).

How Long Should Your Grow Lights Be ON Each Day For Best Results

How far away should hydroponic light be?

As an unofficial rule of thumb, many growers work on the basis that: You need 20-40 watts of power per square foot. Lower wattage LEDs of around 200 watts should sit between 12-20 inches from the top of the plant. Higher wattage LEDs of 1000 watts and above should sit between 36-46 inches from the top of the plant.

How much does it cost to run an LED light bulb for 24 hours?

On average, a 10W LED light bulb used for 24 hours will cost about $0.10 to $0.20. This is significantly less than traditional incandescent bulbs, making LED bulbs a cost-effective and energy-efficient choice for both indoor and outdoor lighting.

Can tomatoes grow in 24 hours of light?

Tomato plants exposed to continuous light (24 h photoperiod) started developing leaf chloroses after 7 weeks of treatments. We observed that, for the first 5 to 7 weeks of treatments, tomato plants grown under continuous light had better growth and higher yields than plants receiving the 14 h photoperiod.

Do grow lights dry out soil?

This is because HPS/CMH lights run much hotter than LEDs, in addition to producing more infrared light, which causes the plants and soil to dry out much faster. This causes the watering routine to be heavier and more frequent than what would be needed under LED lights.

What happens if you leave a grow light on too long?

Possible Stress to Plants from Extended Light Exposure

Extended light exposure can potentially cause stress to plants. While plants require a certain amount of light for growth and photosynthesis, leaving grow lights on for 24 hours a day can have detrimental effects.

What are three common mistakes people make when growing hydroponically?

Unleashing Success: Avoid Common Mistakes in Indoor Hydroponic Gardening
  • Neglecting Proper Lighting. ...
  • Overlooking pH Levels: ...
  • Poor Nutrient Management: ...
  • Inadequate Air Circulation: ...
  • Ignoring Temperature and Humidity: ...
  • Clogging and Disruptions in Waterflow:

What does light stress look like?

If a plant is getting too much light and suffering from high light stress, its leaves may look as though they have burned or simply are falling off. In many cases, the soil will be dry to the touch, too.

Should hydroponics be in direct sunlight?

Hydroponic plants need light, not necessarily sunlight, plus they also need the dark, all of which will be covered in this article. In hydroponics, light is typically provided by grow lights. Hydroponic systems can also be set up in greenhouses, in which case plants would get sunlight.

What is the light schedule for hydroponics?

3. How Many Hours Should a Grow Light Be On?
  • Seedling Stage: 16-18 hours of light per day.
  • Vegetative Stage: 18-24 hours of light per day.
  • Flowering Stage: 12 hours of light and 12 hours of darkness per day.

How often do you change water in hydroponic plants?

If your water quality checks flag problems such as smelly water, improper EC, pH and temperature levels, and the presence of algae and sediment, it's time to change your water. Even if you don't notice any obvious issues, as a general rule of thumb hydroponic water should be typically changed every two to three weeks.

What color should the light be in hydroponic setups?

You will need both warm and cool colored lights to ensure your plants are as healthy as possible. Cool-colored lights in the 400-520 nm range are essential for plant growth, while warmer lights in the 610-720 nm range will help your plants flower and bud.

How to tell if your grow light is too close?

Signs of light burn in cannabis plants include upward-pointing leaves and what is known as “bleaching”. Bleaching is the white or yellow discoloration on the leaves closest to the light. Light burn can also be identified when the plant veins stain green as the rest of the leaves turn yellow.

Why are my plants dying under a grow light?

Without sufficient cooling and/or ventilation, the heat generated by the lights accumulates, creating an environment that's uncomfortably warm for your plants. Elevated temperatures can lead to wilting, slowed growth, or even irreversible plant damage.

When should I stop using grow lights?

You should stop using grow lights under the following circumstances: Light Degradation: If your grow lights have significantly diminished in brightness or effectiveness, it's time to stop using them and consider replacing them to ensure your plants continue to receive adequate light for growth.

How much light do hydroponic tomatoes need?

Step 5: Provide artificial lighting for your indoor hydroponic cherry tomato cultivation. We know that plants rely on photosynthesis for their growth, and typically, plants require 12-16 hours of light exposure.

What happens if I leave my grow lights on all night?

In a 24/7 light cycle, plants' natural photoperiodic cues are disrupted, affecting flowering, growth, and dormancy: Flowering: Continuous light can hinder flowering, causing abnormal patterns like premature or delayed blooming.

Is morning sun better for tomato plants?

Tomatoes prefer the morning sun. Morning sunlight dries the dew on the plants, reducing the chances of fungal diseases. It also provides quality exposure to initiate the daily growth cycle.

Is it cheaper to leave LED lights on all the time?

Turning off your LED bulbs when not in use may reduce the amount of electricity your lighting takes up and, in return, could lower some of your energy charges. If you are looking for a more energy-efficient and budget-friendly lighting source, LEDs might be for you.

How much does a 1000 watt LED grow light cost per month?

Example. Assuming your electricity cost is $0.15 per kWh and you run the grow light for 18 hours per day. Therefore, the estimated monthly cost of running a 1000 watt LED grow light in this example is $81.

What uses the most electricity in a house?

Heating and cooling are by far the greatest energy users in the home, making up around 40% of your electric bill. Other big users are washers, dryers, ovens, and stoves. Electronic devices like laptops and TVs are usually pretty cheap to run, but of course, it can all add up.

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