25/07/2022

Autoflowering cannabis plants – how to optimise the light cycle

What is the best light cycle for autoflowering cannabis plants?

Many people find autoflowering cannabis plants very easy to grow. It’s like plugging in an electric stove and letting it do its job. But that doesn’t mean they don’t have certain needs, even though they are a bit easier to grow compared to photoperiodic seeds.

Autoflowers bloom according to their age, not their light cycle. Even so, you need to give the plant the necessary amount of light to get the most out of it.

The importance of the light cycle for autoflowering cannabis plants

There is only one goal when growing cannabis – to have the biggest yield possible with potent flowers. You can get good results without a regulated light/dark cycle, but it will never be the best. Only with good light will the quality be exceptional, the flowers excellent and the plant healthier overall.
We have several options on what type of light cycle to choose. The problem is that it is difficult to choose the best option as each has its pros and cons. The important thing is to monitor the cannabis plants during growth and flowering and adjust their lighting regime if necessary.

Light cycle 18/6 – popular with autoflowering cannabis growers

18/6 light cycle

In this cycle, your autoflowering cannabis plants are exposed to light for 18 hours and are in the dark for the remaining 6 hours. This light strategy is ideal for promoting the early vegetative phase and is also very good for boosting the flowering phase. Many growers like this method. It will make your marijuana seeds grow into beautiful plants that will look lush and produce a harvest that will be well worth it. With this light cycle, you won’t have as high energy consumption, but you will need to set a precise timer to keep the regime.

Mode 20/4 – Stronger version with a little rest

20/4 light cycle

This option is also very popular among marijuana growers. Your plants will have a bit more light and there will be a chance of a larger yield and they will also have a bit of that rest, compared to the 24hr light cycle. Unfortunately, there is a downside here too through setting a timer and accepting the fact that it will cost you some extra money, compared to the 18/6 method.

Cycle 24 – autoflowers with huge yields

24 light cycle

This technique is used in situations where you want to get the absolute most out of your plants. But through this method, there is conjecture among marijuana growers. One group of growers claim that this method is the best in terms of yield. The other group is of the opinion that the plant should have at least some time to “regenerate”. So they recommend changing to an 18/6 or 20/4 light cycle so that there is at least a phase of sleep. The advantage is that you don’t have to have any timer on. However, the downside could be in the form of the electricity bill, as it’s not exactly cheap to light cannabis plants on a 24/7 cycle.

The 12/12 light cycle – a balanced method for autoflowering cannabis plants?

12/12 light cycle

There is also an option to start with a balanced clock cycle. The results from this marijuana growing technique should be satisfactory, but there is the problem that your won’t get as much light during the vegetative phase. As with the 18/6, you will have to rely on a timer and switching between day and night. The advantage here is that this method is not as energy intensive.

How do I ensure the optimum light cycle for autoflowering cannabis plants when growing outdoors?

When growing cannabis indoors, following the time cycle is relatively easy, but what to do with autoflowers outdoors?

autoflowering cannabis platnts under the sky

It will depend on what climate you live in. For those of you who live closer to the equator, we have good news. With a Mediterranean climate, your plants will have plenty of sunshine and therefore the energy they need to grow. Simply take the seeds of your favourite autoflower, plant them and then put your plants in the desired location. However, beware of excessive temperatures, which often exceed 30°. On days with this extreme temperature, keep an eye on the plants. The heat can cause the leaves to bend and twist and the overall growth can be stunned. It’s important to water your autoflowering cannabis plants regularly and move them into the shade if necessary.

Even in milder climates, you can get great results with autoflowers outdoors. All you need to do is time the planting of the seeds for the hottest days of the season and find a suitable spot where they will be in the sunlight for as long as possible.

The ability to schedule the flowering phase for the best months is the biggest advantage of automatic varieties.

Should the light cycle change for autoflowering cannabis plants?

This is not necessary, the automatic cannabis plant switches to the flowering phase on its own after reaching a certain age (usually after 1 month of vegetation). It’s not a problem if you decide to change the light cycle for some reason, but do it in such a way that you don’t send the plants to sleep twice in one day. Intermittent, shifting and otherwise non-routine light cycle is harmful to autoflowers as a form of stress, so try to avoid this.

Published by Jan Veselý

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