How Long Should Grow Lights Be On House Plants

Grow lights should be left on for at least 8 to 10 hours per day to simulate the duration of exposure to natural sunlight that plants generally receive in a day. Automating this procedure by setting your grow lights on timers will prevent you from forgetting to turn them on or off. Light timers are available online and at most big-box retailers.

How long should plants be grown indoors under grow lights?

A grow light’s optimal on time truly depends on a few variables. They consist of the specific light you’re utilizing, the surroundings your plant is in, and the purpose for which you’re employing the light (eg, foliage growth, vegetables or flowering).

You should be given precise instructions for using the light. But here are some general pointers.

  • Grow lights should be on for at least 8 to 10 hours each day in order to be successful. Depending on the situation, this can change from one to sixteen hours. It is better to choose an energy-efficient type when they need to be left on all day, which is why LED grow lights are so well-liked.
  • A grow lamp should always be placed above the plant. It imitates sunlight. The greatest option is always to place plants above a light source since they will gravitate there naturally.
  • Check to see if your grow light is touching or getting too close to plants if it starts to heat up.
  • Young plants or those that prefer the shade can survive with weaker grow lights, however larger plants and those with enormous leaves that can soak up a lot of light (like fiddle leaf figs) can benefit greatly from a stronger light.

How long should you give plants a grow light?

However, certain plants require more light than that, and grow lights differ substantially in terms of light quality and intensity.

While high-intensity grow lights may only need to be used for 10–14 hours per day, low- and medium-intensity grow lights should be left on for longer (18–22 hours).

You must first consider how much light the plant need. For instance, spinach and other leafy greens require less light than flowering plants.

Consideration should also be given to nearby light sources. Having a nearby window or a huge artificial light can cut down on the amount of time you need to spend using the grow light each day.

The age of the plant should also be taken into consideration. More light is required by seedlings than by mature plants. Think about how the two contrast.

How long should plants be exposed to artificial light?

It can be challenging to provide plants the right amount of light while they are being grown inside in order to keep them happy and healthy. Winter has arrived, which further reduces the quantity of natural sunlight accessible because the days are shorter and the nights are longer. At this time of year, the sun’s strength is also lessened. Artificial lighting should be used to augment or replace natural sunshine in order to cultivate healthy, beautiful houseplants and to maintain the bloom of blooming plants throughout the winter.

The light that a plant is exposed to must closely resemble sunshine for healthy growth. All of the hues in the spectrum are present in sunlight, and each is essential for the process of photosynthesis. Two of the most essential hues for the growth of plants are red and blue. Red encourages vegetative growth and flowering, but too much of it will make a plant lanky and strained. A fuller, stockier plant results from blue’s control of plant growth. Select a full-spectrum fluorescent gro-bulb for the best effects. For the healthiest and most vibrant houseplants, this lighting option is ideal.

Varying plant species require different levels of light. While some plants like dim lighting, others need intense light. The wattage of the lightbulb and the distance between the light source and the plant dictate the amount of light that is produced by artificial lighting. Knowing which plants to gather together beneath the fixture and where to position a light will tremendously aid you when choosing where to do so. Plants produced primarily for their leaves typically need less light than those grown for fruit and flowers, as a general rule of thumb. Plants exposed to artificial light should be rotated every week because the light from tube-style bulbs is stronger in the middle than at the ends. To enhance the quantity of light available to your plants, use white trays, mirrors, or trays lined with foil.

The majority of houseplants thrive with 12–16 hours a day of artificial fluorescent light. A plant will grow tall and spindly if it receives insufficient light, and it will wilt, lose color, have overly dry soil, and burn its leaf if it receives too much light. Each day, plants too need to take a break. Your plants’ development rate will be slowed down by an 8–12 hour period of darkness each day, which will also provide them the rest they need to form flower buds. For instance, the Christmas cactus requires six weeks of uninterrupted darkness—13 hours each day—to set bloom buds. The Christmas cactus won’t flower if it doesn’t get the necessary amount of downtime. To control the length of time your indoor plants are exposed to light and darkness, use an automatic timer.

The ability of the fixture to be adjusted is crucial when picking a plant light fixture. The fixture should be movable up and down to accommodate the various plant species’ differing needs for light intensity and growth height. You will be limited in the kinds of plants you can grow and how much you can use the fixture if it is not adjustable. Both adjustable shop lights and tabletop light fixtures are suitable for illuminating indoor plants. The size of the fixture is another factor. The amount of plants you intend to grow below the light should guide your size selection. Plants can be grown on multiple levels of lighting shelves that are provided by illuminated plant carts. While tabletop fixtures are lightweight and may be moved to new locations when needed, carts have wheels that make them portable.

Starting to use artificial light sources may seem scary, but you’ll be astonished at the impact it will make to all of your indoor plants, both houseplants and seedlings.

Can grow lights be left on for too long?

While it comes to making sure that a habit is created when exposing your plants or crops to light, you need a plan.

To keep things simple, all you need is an alarm to tell you when to turn on and off the grow lights. You can use a light timer that you can integrate into your grow light system if you don’t mind paying more money.

This implies that you may simply set a timer to control when the grow lights should switch on and off automatically. In this video, the setting up of an analog grow light timer is demonstrated.

It’s vital to be aware of whether the plants you’ve chosen to grow are low-light, medium-light, or high-light ones. Medium-light plants would require around six hours of light exposure, compared to about four hours for low-light plants.

Some high-light plants require 14–16 hours of exposure to electric lights. You may always check the seed box if you’re unsure of what high, medium, and low-light plants are.

Here is a guide that you can use if there is no indication of how much light your plants require:

High-light Plants

  • Planta Araucaria
  • Palm Tree in a Ponytail
  • Yucca Tree
  • Benjamina Ficus
  • Plant, Ming Aralia
  • The ficus adularia
  • Petra Codiaeum
  • Lutescent Chrysalidocarpus
  • ‘Ole Vera’
  • Coleus
  • Boar’s Head

Low-Light Plants

  • Fern in maidenhair
  • Red Stag Fern
  • Philodendron
  • Viper Plant
  • Avocado Fern
  • Fig Weeping
  • Animal Ear
  • Fittonia
  • Tree of Heaven Fern
  • Star, Earth

These are only a few examples of plants that fit within the categories mentioned above. Keep this in mind as you determine how long to leave your grow lights on and off.

What Happens When Plants are Over-Exposed to Light?

If plants are exposed to light for an excessive amount of time, they will produce more energy than they can need.

If you leave them under your grow lights for too long, it can kill your plant, leaving you with nothing but dead and wilted plants. Yellow dots on a plant’s leaves are a warning that it is absorbing too much light.

Reduce the amount of light your plants or crops are exposed to if you notice these yellow patches on their leaves.

What Happens When Plants are Not Properly Exposed to Light?

To address your question straight, your plants won’t survive since they won’t have enough time to complete photosynthesis and generate enough energy to flourish.

It is strongly advised to purchase a backup generator if you are an indoor grower with a large number of plants and crops so that you can keep your grow lights running in the event of extended power outages.

Do I need to keep my grow lights on at night?

A: My plants will develop more quickly if I give them light all day, am I right? I believe that all I need to do is leave the lights on for them to transform into monsters!

A: Generally speaking, grow lights shouldn’t be left on all the time. For optimum growth, plants require a cycle of light and darkness. They supposedly do “rest during periods of darkness, and possibly utilise this time to transfer nutrients into their extremities while taking a break from growth,” according to theory.

Knowing that basic truth, keep in mind that most plants require at least 12 hours of light each day, of varied intensities. Your hydroponic plants’ precise requirements for sunshine as they develop and bloom can be found in your plant manuals.

Of course, you can place the lights over your hydroponic garden on a timer to ensure that your plants always receive the proper quantity of light. You never have to stress about forgetting to switch things on or off when you have a timer.

Can plants be burnt by LED grow lights?

Light won’t likely burn your plants, not even bright light. Although it won’t technically burn a plant, too much light might challenge your crops and have the opposite effect.

Is it okay to relax next to a grow light?

Discussions about the potential health effects to people have also been sparked by the rapid expansion of LED technology in horticulture lighting applications. This is partially caused by how differently the light in these applications appears visually (in terms of color and intensity).

Any sort of light, from any source, has the ability to cause damage to the eyes or skin at high enough intensities by sustained thermal exposure or photochemical effects of ultraviolet, blue, and/or infrared emissions. Blue light with shorter wavelengths and higher energy (400 and 500 nm) can harm the retina due to photochemical reaction and high intensity. Light sources with a higher concentration will provide more direct energy and pose a greater risk. For instance, gazing at a bright blue sky (scattered blue light) carries little risk, yet staring straight at the sun can nearly immediately cause irreparable harm.

Always avoid staring directly at intense light sources for long periods of time, especially up close. In reality, no one deliberately looks straight at a bright light source for very long. Common sense dictates that prolonged direct eye exposure to a potentially harmful light source will be avoided, and the human innate aversion reflex (we instinctively close our eyes or turn away) further supports this.

According to EN 62471, the standard for the photobiological safety of lamps and lamp systems, LED grow lights must also be evaluated for photobiological safety. This also includes 200 nm to 3000 nm spectral analysis of thermal and blue light. The EN 62471 exposure limit categories reflect the circumstances in which it is thought that the majority of persons could be exposed repeatedly without suffering negative health consequences. The rating simply identifies possible risk, it should be highlighted. Depending on use, the risk could not even materialize as a danger.

Since the eye is a complicated organ, it naturally strives to adjust to different lighting situations, therefore LED grow light spectra may not always appear as expected “natural for people. Changes in lighting conditions for the human eye, such as moving from an LED-lit growth environment to natural daylight, may momentarily impair color vision as the eye adjusts. This is normal, thus it shouldn’t be construed as being a possibility “injury brought on by LED light exposure.

In conclusion, it can be claimed that when designed, installed, and used in compliance with the relevant standards, regulations, and manufacturer’s instructions, commercially available LED light sources (for horticultural or other purposes) can be regarded human safe. Overall, LED grow lights are comparable to other lighting technologies in terms of photobiological safety.

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The biologists and engineers at Valoya write the blog entries. All of the content is unique and intended to aid in the better knowledge of LED grow light technology by researchers and growers.

Where ought grow lights to be placed?

* Depending on the grow light being utilized, coverage will change. Here, an LED source is used without a reflector to direct the light.

Table 1 displays the performance of a 600W LED grow light at different distances from the plant canopy. It provides PPFD (mol/m-2/s-1 or micromoles per square meter per second), describes light intensity (lux), and also displays the “light footprint or canopy coverage.” The distance between the light source and the plant canopy has an impact on the intensity, PPFD/ PAR, and “light footprint.”

Table 1 also shows how shifting the location of a 600 watt LED light affects the amount of light a plant receives and its “canopy coverage.” The light intensity rises as the light source gets closer to the canopy. Grow lights should typically be installed higher up (far away from) the plant canopy during the vegetative stages of growth and lower down (closer to) the plant canopy during the flowering phases of growth.