Should You Leave Grow Lights On 24/7?

Grow lights give homeowners the chance to liven up their homes and create a comfortable atmosphere. After all, no gardeners look forward to saying goodbye to their plants at the end of summer each year. So, should you leave your grow lights on 24/7?

You should not leave your grow lights on 24/7 as doing so can weaken and even kill your plants. Plants need at least a 6-hour break from light so they can recover and grow. Leaving grow lights on all the time can also scorch your plants, make leaves drop, and raise your energy bill significantly.

Some grow lights can even heat your house and trigger the AC to turn on if you run them for too long. It may seem like a good idea to run your grow lights all day, but that's not the case. Follow along as we explore what happens if you leave grow lights on 24/7.

Should You Leave Grow Lights On All The Time?

You should never leave your grow lights on all the time. Grow lights are necessary to grow indoor plants, but you only need to run them for 8-10 hours. This lets you mimic the standard sunlight conditions that your plants would experience outdoors.

A day-to-night cycle is necessary for nearly every plant to thrive and survive. Some homeowners even leave their grow lights on for up to 18 hours, although that is somewhat excessive. That said, an 18-hour light cycle is fine in many cases because it provides 6 hours of rest.

In most cases, 6 hours is the bare minimum amount of time that plants need a break from light. Much like humans, plants have a circadian rhythm and need plenty of rest to thrive.

What Happens If You Leave Grow Lights On 24 Hours A Day?

1. You May Scorch Your Plants

You can easily scorch your indoor plants if you leave grow lights on 24/7. This can also happen if you place your grow lights too close to your plants. You may notice that the room you keep your indoor plants in gets hot.

While most of the energy turns the light on, some of it generates heat. Scorch spots can form on your plants if you run the grow lights for too long. Not only are these spots unattractive, but they can also harm your plants.

Scorched leaves may die and fall from your plants due to the excessive heat. This ultimately wastes a lot of your progress and hard work. Granted, this may not happen if you leave your grow lights on for too long only one time. However, you shouldn’t make a habit of it.

2. Your Plants Will Become Weak

Light is essential for plants to grow, but only in appropriate amounts. Excessive light may speed up their growth at first, but not for long. Eventually, excessive light can weaken your plants and have the reverse effect, hindering their growth.

Plants need to rest for at least 6 hours daily before they get more sunlight. Without rest, plants are susceptible to disease and fungal infections that can eventually kill them. You may also notice weak stems, stalks, and leaves on a plant that have been exposed to prolonged light.

3. High Energy Bills

Running your grow lights 24/7 is unnecessary, harmful, and expensive. Many homeowners quickly notice their energy bills increase once they start growing indoor plants. This increase comes from running grow lights for 8-10 hours per day.

You can triple the cost of running grow lights if you leave them on for 24 hours a day. It’s an unnecessary cost that ultimately has no payoff. Not only will you spend a fortune to run them, but you will most likely harm your plants in the process.

Running grow lights for too long can also increase your energy bills because of the heat they generate. That’s especially true if you live in a small house or apartment without much ventilation. This may cause your air conditioner to run more often to keep up with the extra heat.

Is 12 Hours Of Grow Light Exposure Too Much?

While 12 hours of grow light is often safe for indoor plants, you shouldn’t exceed it. Some tropical plants can even benefit from getting 12 hours of light daily. However, they can often get by just as fine with no more than 10 hours of grow light.

Some people run grow lights for 18 hours, but that is ultimately a waste of money. It can lead to faster growth results at first, but will eventually weaken the plants. That said, running your grow lights for 12 hours a day is fine, as they will get 12 hours of rest.

Can Indoor Plants Go Without Light for 24 Hours?

Indoor plants can typically go without light for 24 hours. Some plants can even go longer without light, although it isn’t ideal for their growth. This is a common question among indoor gardeners, especially those who are concerned about power outages.

Temperature is the biggest thing to consider for your plants when it comes to a power outage. The temperature can quickly plummet during a power outage, especially during the fall and winter. Indoor plants typically require an indoor temperature of 65 to 70 degrees Fahrenheit at a minimum.

You can combat the cold temperatures with a gas or battery-operated space heater when the power goes out. However, you must be careful and make sure no objects or fabrics are near your space heater. That is a huge fire hazard, which isn’t worth the risk even if your plants are cold.

What Time Should You Turn Grow Lights On For Indoor Plants?

Many homeowners turn their grow lights on in the morning between 7 AM and 10 AM. The best time to turn on your grow lights depends on how long you run them. For example, it’s a great idea to turn the lights on at 7 AM or 8 AM if you run a 12-hour cycle.

That way, you can easily turn your grow lights off at night, as it won’t be too late. You may forget to turn your grow lights off if you wait too long to turn them on in the morning. That’s because they would need to run until later in the day, and you may simply forget or fall asleep.

Luckily, you can program many grow lights to turn on and off at specific times. This comes in handy if you go out of town or simply have a busy work schedule.

Summing It Up

Don’t leave your grow lights on 24/7, or else you may scorch your plants and damage their leaves. This can mess up their circadian rhythm, as your plants won’t have any time to rest. Running your grow lights too long can also lead to exorbitantly high energy bills, so it’s not worth it.

Related Guides:

• How To Make Indoor Plants Grow Faster
• Do Houseplants Improve Indoor Air Quality?