One of the first decisions growers make before planting is choosing between photoperiod and autoflowering medicinal plants strains. Autoflowering medicinal plants are easy to cultivate – especially if you follow a good autoflower light schedule – and can be harvested within a shorter period.

By contrast, photoperiod strains produce much higher yields but they require more space, specific skills and light changes to induce flowering. 

In this light schedule for autoflowers guide, you’ll learn about the different light options for growing autoflowers and which is the best one to use for your cultivar.

Do autoflowers need darkness?

  • Compared to photoperiod strains that require at least 12 hours of darkness to trigger the flowering cycle, autoflowers don’t depend on darkness to flower. They automatically produce buds when they mature.
  • Some growers use autoflower light schedules that deprive autoflower plants from light for a number of hours each day. As long as the dark period does not exceed 6 hours, the crop will still provide a high yield.
  • If the exposure to brightness drops below 18 hours, you’re likely to get smaller plants and a reduced harvest.

Autoflowering vegetative and flowering stages

  • Photoperiods and autoflowering medicinal plants go through a vegetative and flowering stage. A plant only grows leaves and stems during the former. It’s in the latter when it starts growing buds.
  • For autoflowers, the vegetative period lasts about 2–4 weeks. Then, the flowering cycle begins.
  • Typically, autoflower strains take 8–12 weeks to go from seed to harvest. Our autoflower seeds have growing times that are as short as seven weeks. Growing these autoflowering medicinal plants seeds feminized will give you a yield in a shorter period.

Which lights are best for autoflowers?

  • With photoperiod plants, growers use blue lights for the vegetative period and more reddish-yellow ones during the flowering period. You can apply the same principle to your auto flower light cycle.
  • During the vegetative stage, provide your plants a blue spectrum that ranges from around 400 to 550nm. This helps medicinal plants grow short and stocky.
  • When they’re in the flowering stage, your autoflowering medicinal plants strains will need a red spectrum, with higher wavelengths from 550 to 700nm, to promote budding and produce large and dense flowers.
  • Keep in mind that you can still produce a successful harvest even if you don’t provide a full spectrum. A medicinal plant will grow healthily as long as it gets bright light with some red and blue.
  • There isn’t a best light for autoflowering medicinal plants. However, you’ll achieve better yields if you give your plants the spectrum they need during each stage.

What are the most popular autoflower light schedule?

Most growers agree that when growing autoflowering medicinal plants indoors, there should be between 18 and 24 hours of light a day. 

The four basic light schedules growers use include: 

  • 18/6 light schedule

The 18/6 light schedule refers to 18 hours of light and 6 hours of darkness. It’s the most typical light cycle for autoflowering medicinal plants plants.

You’ll save on energy and the fewer hours of darkness allow the plants to rest, promoting robust growth. If you live where there’s lots of sunlight, you can switch off your lights during the six hottest hours of the day.

Your plants get time to rest.
You save money and energy because the process consumes less electricity than the 24/0 cycle.
You’ll need a timer.
Your plant doesn’t grow as fast as in a 24/0 schedule.

  • 24/0 autoflower light schedule

This cycle is perfect if you’re growing autoflowering plants in a cold climate. Leaving your LED or HPS lights on 24/7 will mean consuming more electricity, but it’ll keep your plants warm, enabling them to develop faster.

Using this autoflower light schedule means you won’t need a timer. Your lights will be on until harvest time.

High possibility of a higher yield.
You don’t need a timer since you don’t need to switch off your lights.
It’s a costly process, as you’ll use more electricity.
Your plants don’t get rest.

  • 20/4 light schedule

The 20/4 light cycle is becoming popular among autoflowering medicinal plants growers because it’s between the 18/6 and 24/0 light schedules. As you don’t leave your lights on the whole day, your plants will get some rest time.

It’s a perfect balance. You’ll have better yield results than the 18/6 schedule, and you don’t spend as much on electricity as in a 24/0 schedule.

  • 12/12 light schedule

Growers usually use the 12/12 autoflower light schedule when they grow these crops in the same tent as photoperiods because it’s the light cycle for the latter.

It’s also the preferred schedule for those with a tight budget who can’t afford the electricity costs of practicing the longer light cycles. 

Then I want to recommend you several ECO Farm LED grow lights.

ECO Farm 700W/860W/1060W Waterproof Samsung 281B / 301B LED Grow Light With UV IR Separately Control


Proper use of UV IR containing luminaires to ensure your plants grow better and get more trichome density and THC content.
The role of UV: Increasing the THC content of plants, only be used in the last two weeks of flowering stage, and if be used at other times in the plants, may have a negative effect on plants.
The role of IR: Increasing the number of flowers , only be used in the early flowering period and stopped once buds begin to appear. This requires the IR and UV must be individually controlled.

UV IR separately control:

IR and UV only need to be opened separately during flowering, so we design IR and UV separately. IR is beneficial to plant flowering and fruiting, and UV can promote the formation of plant THC and CBD.

  • Easier and more effective dimmer switch: can adjust brightness from 0% to 100%to adapt the needs of plants in different stages of seeding, veg and flower, which making you planting easier
  • Group Control The Lights: It is equipped with an external RJ 14 cable and allows you to install up to 200 fixtures per controller by simply daisy chain. Easy to dimming and control a lot of fixtures for you. Gospel for commercial
  • True IP65 protection against water and dust
  • Five-year warranty, 10000 hours on UV diodes

ECO Farm ECOX 480W/600W/800W/1000W Dimmable Samsung 301B Chips High Efficiency LED Grow Light


  • ECO Farm ECOX series dimmable three channel dimming light strip is more suitable for indoor plants whole grow stage. The dimmer knob to adjust according to the needs of the plants, in order to obtain perfect growth performance, which enhance high yields to obtain the ideal harvest.
  • Easy to install, high energy efficiency with 2.9umol/J
  • ECO Farm ECOX light uses full-spectrum white samsung 301B diodes, 660nm deep red diodes, 730nm IR diodes, 395nm UV diodes, which provides desired needs for plants seedling to harvest growth with full spectrum led grow lights and provides better light-spectrum coverage, maximum PAR output at various distances.
  • ECO Farm led grow light makes your home grow life quiet, and this growth lamp used reliable driver and high effective aluminum heat sink to ensure heat dissipation and long lifespan.

ECO Farm 600W Assemble Samsung 301H LED Grow Light Adjustable Beam With Meanwell HLG 600H 54B Driver


  • ECO Farm 600W LED light is a high-performance top-lighting solution for commercial horticulture cultivation. Designed for growers to push the envelope with high-PPFD cultivation practices.
  • The updated structure with an adjustable beam distribution rack and offers the possibility of adjusting the 600W LED grow light concentration along the rods, making application in different areas more flexible.
  • It also has an anti-sulfur coating unique to horticulture, which further increases the chip's durability.
  • Optimized full-spectrum, suitable for all growing stages from seed to harvest
  • In addition, Meanwell HLG 600H 54B driver with high voltage capacitors, ensuring LED chips lifetime of up to 50,000 hours.
  • The latest high-efficiency Samsung 301H 3500K chips + Epistar 660nm chips, with much better PAR efficiency results.
  • Certification: CE, EMC, FCC, LVD,
  • Warranty: 3-year

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