When it comes to growing autoflowers, one of the biggest perks is how low-maintenance they are compared to photoperiod strains. Autoflowering cannabis plants are genetically designed to flower on their own after a set period of time, regardless of how much light they receive. But that doesn’t mean light cycles don’t matter! In fact, picking the right one can have a huge impact on your plant’s yield, growth speed, and health. Let’s dive into the different light cycles and how to make the best choice for your autoflower grow.
Understanding Autoflowering Cannabis Plants
What Makes Autoflowers Different from Photoperiod Strains
Unlike photoperiod cannabis plants, autoflowers don’t need a change in light schedule to start flowering. Photoperiod strains are kind of fussy — they need a precise switch from long days to short days to signal when it’s time to flower. Autoflowers, though, are on autopilot. Whether they’re getting 24 hours of light or just 12, they’ll flower after a set amount of time, usually around 2 to 4 weeks from sprouting. That’s what makes them super easy for beginners or growers who don’t want to stress about changing light schedules.
Why Autoflowers Don’t Rely on Light Cycles for Flowering
Autoflowers are a hybrid of Cannabis sativa or Cannabis indica and Cannabis ruderalis, which is a wild species that naturally grows in places with short summers and harsh conditions (think Russia). Ruderalis evolved to flower quickly without needing a shift in light. So, autoflowers have inherited this trait — they flower based on age, not the light they get. This means you don’t have to worry about mimicking outdoor seasons like you do with photoperiod plants.
The Most Popular Light Cycles for Autoflowers
The 18/6 Light Cycle Explained
The 18/6 light cycle is a favorite among autoflower growers. It means 18 hours of light followed by 6 hours of darkness each day. It’s kind of the “happy medium” for autoflowers. They get plenty of light for robust growth, but they also get a little break in the dark. Think of it like your plants’ nap time — a chance to rest and reset, which can be important for healthy development.
Benefits of the 18/6 Light Cycle for Autoflowers
I’ve found that autoflowers really thrive on this schedule. The 18 hours of light provide enough energy for strong vegetative growth and big buds, while the 6 hours of darkness help avoid overexertion. Plus, this cycle helps you manage electricity costs without sacrificing too much growth potential. Your plants will be happy, and so will your wallet.
The 20/4 Light Cycle – Advantages and Considerations
Some growers push things a bit further with a 20/4 cycle — 20 hours of light and only 4 hours of darkness. This gives the plant more light exposure, which can lead to slightly faster growth and potentially bigger yields. But it’s a fine balance. While more light is good, your plants still need downtime, and too little dark time might stress them out.
The 24/0 Light Cycle – Is Constant Light Beneficial?
Now, you might be thinking, “Why not just keep the lights on all the time?” Well, some people do! The 24/0 cycle is exactly that — no darkness at all. And yes, your autoflowers will grow under constant light. However, I wouldn’t recommend it long-term. Constant light can stress your plants, leading to slower growth over time or reduced yields. And let’s face it, everyone (even plants) needs some sleep!
Comparing Different Light Cycles – Which Is Best?
So, which one is best? It really depends on your growing space and personal preferences. If you want to keep things simple and conserve energy, go for the 18/6 cycle. If you’re looking for faster growth and bigger yields, the 20/4 cycle might be worth a try. But if you’re feeling experimental and have the setup for it, the 24/0 cycle can work — just keep an eye on your plants for signs of stress.
How to Adjust Light Cycles for Indoor Autoflower Grows
Impact of Light Cycle on Growth Stages
Autoflowers don’t need specific light to flower, but light does impact how fast they grow during their vegetative stage. More light generally equals faster growth, especially in the early stages. But once they start flowering, you’ll notice less dramatic growth changes based on light cycles. So, while you can tweak light cycles, don’t expect a huge shift once flowering begins.
How to Optimize Light Intensity Along with Light Cycles
It’s not just about how long your lights are on — the intensity matters too. I like to use high-efficiency LED lights for my autoflowers because they give off less heat and provide strong light at different spectrums. Positioning is key, too. Keep your lights close enough to the canopy to boost growth but not so close that you burn your plants. You’re looking for that sweet spot where the plants are happy and soaking in the rays.
Do Autoflowers Need Darkness?
Yes! Even though autoflowers don’t need darkness to flower, they benefit from it. Darkness gives them a chance to rest and recover from the intense photosynthesis happening during light hours. I’ve noticed that autoflowers seem healthier and produce more when they get a little dark time. Plus, this helps mimic their natural environment.
How to Adjust Light Cycles for Specific Strains
Not all autoflowers are the same. Some strains might thrive with more light, while others are happier with a bit more darkness. If you’re growing a strain that’s known for being a heavy yielder, try giving it a longer light cycle, like 20/4. But for smaller strains or those that are more sensitive, sticking to 18/6 is usually your safest bet.
Environmental Factors to Consider with Light Cycles
Temperature and Humidity Control During Light and Dark Phases
When your lights are on, temperatures are going to rise, and so will the humidity. During the dark period, temps drop. You want to make sure there’s not too much fluctuation between the light and dark phases. I use fans and dehumidifiers to keep things stable. This also helps prevent issues like mold and pests.
Managing Electricity Costs with Different Light Cycles
Electricity bills can get pretty high when you’re running grow lights for 18 or 20 hours a day. But don’t worry — you can still manage costs. Opt for energy-efficient lights like LEDs, and consider using timers to keep everything on schedule without wasting energy. Running a 24/0 cycle will cost you the most, so if you’re budget-conscious, stick to 18/6 or 20/4.
Common Mistakes with Autoflower Light Cycles and How to Avoid Them
Overexposure to Light – What to Watch For
Too much light can cause stress. Your plants might grow slower or start showing signs of light burn, like curling leaves or yellow spots. If you’re running a 24/0 cycle and notice these issues, try switching to 18/6 or 20/4 and see if your plants perk up.
Not Providing Enough Light – Signs and Solutions
On the flip side, too little light can stunt your autoflowers. If your plants are looking leggy, with long stems and small leaves, they’re probably not getting enough light. Either increase the hours of light they get or move your lights closer to the plants to give them a boost.
What light cycle is best for autoflowers?
18/6 is the most common light cycle for autoflowers, offering a balance of energy and rest.
Can autoflowers grow under 24 hours of light?
Yes, they can, but constant light can stress the plants and reduce yields over time.
Should I change the light cycle during flowering for autoflowers?
No, you don’t need to change the light cycle since autoflowers flower based on age, not light.
What happens if autoflowers get too much light?
Too much light can cause light burn, slow growth, and stress. Reduce light hours if this happens.
How many hours of light do autoflowers need daily?
Autoflowers can thrive on 18-24 hours of light, but 18/6 is a great balance for healthy growth.
When it comes to autoflowers, you’ve got a lot of flexibility with light cycles. The best option depends on your goals and setup. I like to stick with the 18/6 schedule for that sweet balance of growth and energy efficiency, but if you want to push for bigger yields, the 20/4 cycle could be your go-to. Just remember to watch your plants and adjust as needed — they’ll tell you what they need!
