Best Timer for Grow Lights (Indoors)

Growing marijuana indoors can require a lot of manual labor. It is worth automating as much of the process as you can, starting with your grow lights.

Photoperiod cannabis needs a fixed light schedule. Growers typically run 16 to 18 hours of light in the vegetative stage and switch to 12 hours of light and 12 of uninterrupted darkness for flowering, per research in Plants.

Light during the dark period can suppress flowering, so a timer that never misses is worth having. This guide is for adults 21+ growing where it is legal.

Can’t wait? Our top pick is the Canagrow Outlet Timer, a good fit for most home growers.

Top 5 Industry-Leading Grow Light Timers

1. Canagrow Outlet Timer

The Canagrow Outlet Timer is a programmable timer that runs your lights on schedule, so nothing stays on longer than it should.

It works with anything you plug into it within its rated load. It’s explicitly designed to meet the needs of indoor grow rooms and can accommodate lights, oscillating fans, and other appliances.

It features a heavy-duty digital display with clearly defined control buttons and a large outlet timer readout that is super easy to read. It supports multiple on/off programs, with daily and weekly repeat options. Check the current listing for the exact number of programs.

Settings repeat automatically, and a backup battery keeps them through a power failure. There is a mode button that allows you to manually turn the device on and off after or before the set time…just in case you make changes to your schedule.

Pros

• Remarkably versatile and customizable design
• Daylight saving time setting adjusts the clock
• The large digital readout is easy to read
• The mode button allows you to operate manually
• Supports multiple on/off programs

Cons

• Check its load rating against your lights before plugging in

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2. Nearpow Dual Digital Light Timer

The Nearpow Dual Outlet Digital Timer is another timer that is easily programmable to meet the needs of your grow space. This is a three-prong timer that can independently control different appliances in your grow room, such as grow lights and fans.

It comes with two independent grow light controller outlets, a large digital readout, and well-defined lighting controller buttons. The housing is flame-retardant plastic, and a backup battery keeps your settings if the power goes out.

It has a random "vacation" mode, but never use random mode on grow lights: it switches at random times and can break your plants' dark period. A daylight saving time setting adjusts the clock, and a child lock protects your settings.

Setting the timer is easy. Just press the second, minute, hour, or week buttons to program time. The digits are visible on the LCD display when setting time.

Pros

• Comes with two independently controlled outlets
• Seven-day programmable with multiple schedules
• Flame-retardant housing
• Backup battery saves settings
• Child lock
• Runs silently

Cons

• The instruction manual is not very intuitive

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3. Dewenwils 2-Pack Indoor Outlet Lamp Timer

You can save energy and money and add a little extra convenience to your grow room by introducing the Dewenwils 2-Pack Indoor Outlet Lamp Timer.

This two-prong timer is compact and lightweight with clearly labeled control buttons, including time, on, off, hour, min, and reset. The device is engineered with a highly vibrant LCD readout that is not only clear but also super easy to decipher.

It is one of the easiest units to program. You’ve got five easy to use control buttons. You only need one set of daily repeat settings.

Unlike mechanical units, this digitally programmed timer will hardly generate any annoying ticking noise in the long-run.

Pros

• Lightweight, compact design that is easy to carry
• Works with plug-in lights that have a two-prong plug and stay within its load rating
• Five easy to use control buttons allow for quick one set of daily repeat settings
• Compact but with a big, simple to decipher digital readout
• Digitally programmed to run quietly

Cons

• Does not come with a manual override

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4. Century 2-Pack Indoor Digital Timer

The Century 2-Pack Indoor Digital Timer is versatile as well as customizable. You can effortlessly set up to eight on/off programs for the separate two grounded outlets.

The most impressive feature of this timer is that it allows you to select individual days or opt to use one of the preset combination days. There is a daylight saving mode that you can easily engage by one press of a button. It also has a backup battery that comes in handy when there is a power failure.

It also has a random vacation mode, which you should leave off for grow lights so the dark period stays intact.

Pros

• Allows you to set up to eight on/off programs
• Comes with two outlets for connecting two light sources
• You can choose between preset combination days or individual days
• Daylight saving time setting adjusts the clock automatically
• The built-in backup battery comes in handy during power failure
• Manual override allows you to operate the device manually

Cons

• It is possible to receive a defective product

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5. GreenLaren Indoor 24-Hour Mechanical Outlet Timer

The GreenLaren Indoor 24-Hour Mechanical Outlet Timer is a responsive and reliable choice of a grow timer.

It uses a 24-hour dial with push-down pins, and you set on and off times in 30-minute steps.

Once set, the schedule repeats daily, and a switch allows manual override. Like other mechanical timers, it stops during a power outage, so check the time afterward. The timer is well-suited for LED bulbs and fluorescents.

Pros

• Easy to program, press pin down to turn on and up to turn off
• 24-hour dial with 30-minute steps
• No technical controls, just set the pins
• Override switch for manual control

Cons

• It ticks a little
• Loses time during power outages

A Guide for Finding the Best Timers for Grow Lights

There are several timers you can choose from. However, you need to be selective in choosing a model that will be safe and reliable.

Here are a few features to consider:

Mechanical Versus Digital

Mechanical timers are a bit old school, but they work. You won’t get as many customization options as you would with a digital timer, and you may be limited to just setting specific on and off hours.

Most mechanical timers on today’s market are fitted with a control knob/dial. You turn the dial to set the timer. These timers tend to function similarly to mechanical alarm clocks. Plug-in mechanical timers are driven by a small electric motor, so they have few extra features.

When compared to digital timers, manual designs can only manage a limited number of zones. They may be suitable for grow lights, but inefficient for more complex appliances. They also don’t function during a power failure. So, you have to reset them every time you have a power outage.

Digital timers are often a better fit for indoor growers. Unlike their mechanical counterparts, digital models come with LCD readouts and an array of built-in functions. Digital versions are fitted with control buttons that are easy to navigate. All you have to do to program the timer is press the appropriate button.

The most contemporary digital timers allow you to program settings for different days of the week. You will even come across digital models that allow different weekly patterns for different times of the year.

Plug-In Versus Direct Connection

When shopping for timers, you’ll come across plug-in timers and direct wire connection timers.

As the name suggests, plug-in models do not need any installation. All you have to do is plug them into the wall socket to power. Direct wire connections need a hard-wire connection/installation into the device you want to use them with.

They can handle bigger loads and more devices, but hardwiring should be done by a licensed electrician.

Load Rating

Every timer has a maximum load printed on it in amps or watts. Add up the wattage of everything you plug in and keep it under that rating, and look for a UL or ETL listing mark.

Final Thoughts

In addition to a good grow tent and hydroponic system, your LED grow lights are a crucial aspect of your grow operation. A timer keeps your light schedule exact, which matters most in flowering, when stray light during the dark period can delay or disrupt buds.

When choosing a timer, we recommend a digital model with battery backup and a load rating above what your lights draw.

Any of the timers on our list, and especially our #1 pick the Canagrow Outlet Timer, make excellent choices for an indoor grow room. It’s just up to what you are looking for and the budget you’ve set for yourself.

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Sources

• Examining the "Night Break" Method in Cannabis sativa Horticulture, Plants (via NIH PMC)
• Ten Frequently Asked Questions About Growing Cannabis, Utah State University Extension