Leaving Grow Lights On 24 Hours

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Last Updated on April 21, 2022

The impact of grow lights in hydroponics gardening is very essential as it mimics the work done by natural sunlight. There’s is no disputing that leaving grow light on for long will result in faster growth. However, the question is: is leaving your grow lights on for 24 hours ideal? Let’s look into this.

Leaving your grow lights on for 24 hours will sure supply your plants more light and if you notice they aren’t getting adequate light, increasing the number of light supply is fine. However, this is usually not the ideal way out and we will let you know why.

Can You Leave Grow Lights On 24 Hours A Day: Ideal Or Not?

It is not the best idea to leave your grow light on for 24 hours even if your plants are not getting enough light supply. The best solution is to obtain more light installations or switch to a stronger grow light. Thus, it’s not ideal to leave your grow light on all day and we will give you more reasons.

Reasons Why Leaving Grow Lights On For 24 Hours Isn’t Ideal

Let’s take a look at some reasons why leaving your grow lights on 24 hours is not recommended:

  1. No Resting Time For Plants: when you run your grow light all day, your plants will have no time to rest. Just like a human being needs rest, plants also require a resting stage. Have in mind that the natural sun does not go up all day. We have the night time which is the dark cycle of the plants. Allow your indoor hydroponics plants to also have this dark cycle. During the dark cycle which is the resting stage, it is believed plants use this period to convey nutrients into the most distant part of the plants.
  2. Not Ideal For The Flowering Phase: 24 hours lighting duration is not ideal for plants that need to enter the flowering phase. Your plants won’t transition into the flowering phase unless you decrease the hours of lightening. Now if your plants are already in their flowering phase and you up the light duration to 24 hours, doing that can be quite catastrophic. This can cause your plant to go back to the vegetative phase and it might even take a long time to return to its flowering phase.
  3. Additional Cost: An additional cost is another reason. More electricity will be used and it might require you to change the bulb frequently.
  4. Additional Heat: more heat is will be emitted when you leave the grow lights all day. It will require you to also run more fans as well as other cooling instruments to control the excess heat.
  5. Puts Stress On Equipment: additional stress is put on your equipment as they are working all day without rest. This can reduce the lifespan of your equipment.

Giixer 1000W LED Grow Light, Dual Switch & Dual Chips Full Spectrum for Hydroponic Indoor Plants

Leaving your grow lights on for 24 hours long has just one advantage. Your plant receives more light and it will result in rapid growth. This is usually ideal for plants that require only the vegetative phase. So, plants like veggies may benefit from this. Nevertheless, the disadvantages of leaving your grow lights on for 24 hours outweigh the advantages.

How To Determine Light Duration: Factors To Consider For 24 Hours Of Light

Put these factors into consideration when deciding the duration to leave grow lights on:

  1. Type Of Plants: there are different types of plants namely low-light, medium-light, and high-light plants. Always determine the type you are growing.
  2. Type Of Grow Light: the types of grow light we have are LED, compact fluorescents, regular bulbs, metal halide, and high-intensity discharge lights. All these grow light supply different capacities of light so you can choose one whichever that suits your growing needs.
  3. Growing Phase: vegetative type of plants may benefit from 24 hours light duration. But flowering and fruiting plants will require a dark phase. The cloning or seedling germination phase is critical so they require both light and dark phases. You can supply them with 12 to 16 hours of light and 8 hours of the dark phase.
How To Determine Light Duration: Factors To Consider For 24 Hours Of Light

What Are The Ideal Hours For Running Grow Light?

It is required to supply your hydroponics plants with at least 12 hours of light and at most 18 hours of light daily. However, if you notice your plants aren’t receiving optimal light you can replace the fixtures or switch to a more powerful light.

Light Output Plants Require

All flowering plants and fruit-bearing plants require 20 to 40 moles of light daily. 18 hours grow light duration can supply 20 moles of light if you make use of LED grow light that has 308 micro-moles of light.

For a 12 hours light duration to produce 20 moles of light, your grow light must be able to supply about 462 micro-moles of light.


What happens if you leave grow lights on all the time?

You’re probably wondering what happens when you leave grow lights on all the time. After all, you’re growing plants and there’s no doubt that they will need to use a lot of energy to do so. If you have ever looked at grow lights before, you may be surprised to find out how much power they actually use.

This is a very interesting question. I’ve had a lot of experience with grow lights and what I do know is that I don’t leave my lights on all the time. I only turn them on when I need them. The first thing that comes to mind is the light spectrum. If you leave your lights on all the time, the spectrum will be different than it would be if you were to turn them on at a specific time. This will affect the quality of the plants, and it could also cause other problems.

Another thing that I’ve noticed is that my lights tend to stay warmer. When I first started using them, they were so bright that I thought they were burning the plants. But as time went on, I discovered that they actually helped the plants by increasing the temperature, which allowed them to grow faster. Now I know this might sound weird to some people, but for me, turning the lights off for a few hours has worked out well. It doesn’t seem to affect the plants much at all.

Why shouldn’t I leave my grow lights on all the time?

You risk burning your plants. This is probably the biggest reason why you shouldn’t leave your grow lights on for 24 hours.

The fact is that when you leave grow lights on for 24 hours, it creates an environment where your plants can use up all of their energy reserves and grow to a point where they can no longer recover. This can result in stunted growth, and even death.

You also risk wasting electricity. It’s true, if you’re using LED grow lights, then you’re going to be using a lot of electricity over the course of 24 hours. If you’re using a 10-watt grow light for 24 hours, then you’re going to be using up 1,000 watts of electricity.

Can seedlings get 24 hours of light?

You may think that this is a time when it would make the most sense to keep them showered in light non-stop, b ut the truth of the matter is that just like mature plants, seeds need to rest after a certain period of time.

What should I consider when it comes to light duration?

Light duration is one of the most important factors to determine the quality of a light. This is because it affects the plants growth, flowering and fruiting cycles. It also affects the light spectrum. You can have a very bright but short light duration. Or you can have a very weak but long light duration.

1.To determine the light duration, you need to know the following factors:

The intensity of the light source

The spectrum of the light

The amount of light emitted at any time

The color temperature of the light source

The size of the plant container

The light source

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