How to Manage Light Interruptions During the Flowering Cycle

Last Updated on April 20, 2022 by Gary Stephen

Every grower knows how crucial light is for the growth and development of any cultivar. Recognizing that light is your plant’s food, we know we must nourish them for healthy growth and the highest quality of produce and yield in the end. But, how to manage light interruptions during the cycle is a common problem that not everyone knows how to tackle.

We may sometimes encounter harsh circumstances, which will hinder the continuous provision of light to the plants. But, even the slightest deviation is enough to hurt its health, especially during the critical flowering cycle.

Fret not, though, my friend! We have written this post to guide you on managing light interruptions. This article will explain the processes involved in the flowering cycle. This will give you a better understanding of its significance. We will also present the possible scenarios that you might experience along the way, providing you with the best solutions applicable to these problems.

The Flowering Light Cycle

We will delve into the different issues and their remedies a little later. But first, let’s understand how the flowering light cycle takes its course. It’s quite interesting!

The flowering cycle gets divided into various substages. They are the Transition, First Buds, Flowering, and Ripening of Buds. The number of hours of exposure to the light versus the darkness varies according to each stage. To give you an overview, see the table below:

SubStage Light Exposure Dark Exposure
Transition 10 to 12 hours 12 to 14 hours
First Buds 8 to 10 hours 14 to 16 hours
Flowering 6 hours 18 hours
Ripening of Buds 0 to 6 hours 18 to 24 hours

Substage 1 – Transition Stage

Transition is the period of progression from the vegetative into the flowering stage. It is the first one to two weeks of the flowering cycle. By this time, the plant is still growing. Thus, there won’t be much of a difference from what’s implemented during the vegetative phase. This transition period needs a light/dark cycle between 12 to 14 hours per day.

Substage 2 – First Buds

For the female plants, the occurrence of the first flower materializes in this stage. It takes the entire third and fourth week of the cycle to develop from a mere hairy pistil into real buds. This phase requires the plants to get exposed to light for at least 8 to 10 hours. Thus, they should also get a little bit more darkness for 14 to 16 hours.

Substage 3 – Flowering

Garden, Flowers, How to Manage Light Interruptions

After the occurrence of the first bud, they will continue to grow and multiply. They will get help from the hormone called Florigen. This hormone is more likely to build-up when the plant gets exposed to darkness. The dark cycle should increase to as much as 18 hours per day. Thus, the light cycle should lessen to only 6 hours to give way for the favorable formation of Florigen.

Substage 4 – Ripening of Buds

During the final stage of flowering, the buds should have matured by now. In this phase, you may choose to maintain 6 hours of light and 18 hours of darkness. For further ripening, most growers carry out a full 24 to 48 hours of complete darkness up until the end of the cycle.

Read Also: Best LED Grow Lights in 2020: Top 10 Reviews & Buyer’s Guide

Reasons for Light Cycle Interruptions

Sometimes, interruptions happen during light cycles, intended or not. Some growers alter the light cycle on purpose to manipulate the progress of the stages. But, there are also unwanted situations beyond the control of the planters. They can cause unsought disruption of the light cycle.

Here are a few of the very common reasons why the provision of light is, for a moment, ceased inside the grow room:

  • Negligence to turn on/off the light switch
  • Malfunctioning of the dial-up timer
  • Light bulb burned out
  • Electricity interruption due to weather disturbances or other service-related factors.
  • Unattended leaks from the vent or door frame

Problems with Light Cycle Interruptions

Regardless of the reason, the plants are extra responsive to light changes. They are very reactive, particularly during the flowering stage. The slightest disturbances are enough to impact the growth and the yield of the cultivar.

Below are some of the scenarios that growers might encounter and how one must handle the issue.

Problem 1 – Regression to Vegetative Stage

The mature plants, when exposed to light for too long, may cause them to regress back to the vegetative stage. Re-vegetation starts when the plants don’t get enough darkness to produce the Florigen.

As mentioned before, florigen thrives well under an environment with very little to no light. Without this hormone, the plant then reverses its process back to a vegetative stage.

Submitting the plant to more than 6 hours of extra light can prompt it to become a hermaphrodite or hermie. It is a condition wherein the plant develops both male and female characteristics.

Solution 1 | How to Manage Light Interruptions

As this is an issue caused by the disruption in the dark cycle, put the plant to darkness as soon as possible. This will help to halt the process of revegetation. So, for example, your normal light cycle is due to end at 12 noon but you forgot to turn it off until 2 PM. When you realize your light cycle is overdue, do a quick dark cycle and catch up with the regular L/D schedule.

As for the hermaphrodites that developed, they are easy to spot as it often looks like a ball. So, go ahead and inspect your plants and remove all the ball-like structures. This is to prevent them from releasing more pollens in the grown room.

Problem 2 – Hastened Maturation of Buds

This is quite the opposite that of scenario #1. When the plants are exposed to too much darkness, the buds tend to grow at a much faster rate. Thus. increasing the production of the florigen hormone. It sounds like an advantage to the growers, but then again we wouldn’t want to push it far beyond its natural course. I won’t hurt to give the plants its much needed time to develop on its own in its full form.

Solution 2 | How to Manage Light Interruptions

As soon as you notice that you went overboard with the dark cycle, turn on the lights to start the light cycle. From there, you may continue again with the regular light/dark cycle periods. You can do this until the buds have grown mature.

Problem 3 – Hermaphrodites

Hermaphrodites means that the cultivar both produces male and female reproductive systems. These two reproductive systems are Staminate and Carpellate. This is either inherent by genetics or brought about by environmental stress. Long hours of interruptions to both light and dark cycles and thermal stress happen. These are a few of the common contributing factors for its changes in gender.

This is generally considered a natural feature, especially on certain strains like Thai Sativa. It is actually least favorable when you are trying to grow cannabis for consumption. That is because hermaphrodites are inclined to produce plants that are less potent and full of seeds. On that note, the quality and quantity of the end product are likely to get compromised.

Solution 3 | How to Manage Light Interruptions

Hermaphrodites can be dealt with quite easily, but is also critical at the same time. All you need to do is to isolate the plant and remove the hermies. But, you need to do this immediately.

You may have realized that long periods of light/dark interruption have undergone. Immediately inspect the plants for the possible formation of hermies. The target of the growers is to produce a healthy female plant. Thus, we would only be targeting to get rid of the developing male flowers.

During the pre-flower stage, it is not difficult to distinguish between the male flower versus the female. The male sex organ looks like a yellowish, banana-shaped flower that balls up to form a sac for the pollens. Meanwhile, the female sex organ appears as a calyx with thorn-like pistils on top.

Now, let’s focus on the male flowers. What we want to happen here is to prevent the sac from opening and releasing the pollen in the atmosphere. you may soon suspect that male flowers have grown in any part of the branches. Immediately isolate these plants outside of the grow room.

Once separated from the healthy ones, be careful in plucking the balls with a tweezer. After that, it is also a good idea to spray the plants with water to sterilize the pollen. Lastly, keep it isolated for at least 10 to 15 days and continue to check the growth of new male flowers.

How to Manage and Prevent Light Cycle Interruptions

1. Regularly check for leaks.

By leaks, we mean cracks or holes in the walls or ceiling. They can let outdoor light enter the grow room unintended and disrupt the dark cycle. Hence, it is ideal to inspect the space every now and then. This is to make sure that there is no light that can seep through inside.

2. Have a backup generator ready on-hand.

You can’t avoid power interruptions caused by weather disturbances or electricity maintenance issues. Also, they’re expected to happen from time to time. On that note, it is a smart decision to have a small back-up generator on hand. For it to supply emergency electricity when the need arises.

Here are some of our recommendations:

WEN 56200i Super Quiet 2000-Watt Portable Inverter Generator

Pulsar G2319N 2300-Watt Gas Powered Quiet Inverter Generator

A-iPower SUA2000iV Super Quiet 2000-Watt POrtable Inverter Generator

3. Use a good quality grow light timer.

This device allows growers to conveniently control the light system along with many other helpful features. One of its key functions is to help on-time initiation of the light and dark cycles. 

Check these items out:

BN-LINK 24 Hour Plug-In Mechanical Grounded Heavy Duty Timer

BN-LINK 7 Day Heavy Duty Digital Programmable Timer

4. Use a climate controller.

This feature-packed device allows the grower to manage more than the light system. It is also capable of controlling the air, temperature, and humidity. Also, to control carbon dioxide and other environmental aspects inside the grow room.

You might want to consider investing in one of the following:

Titan Controls Digital Environmental Controller – Saturn 6

iPonic 624 Two-Zone Environmental Grow Room Controller

Should I change my lighting during the flowering stage?

At this stage in the growing process, almost everything about the flowering is nearly complete, so there’s no reason to adapt your light cycle too much. Instead, focus on keeping the lights on for about 6 hours and give your plants a dose of darkness for around 18 hours, depending on the pant you are growing. Some growers even choose to provide uninterrupted hors of darkness leading up to the ripening process,  which can be anything from 24 hours to 48 hours of absolute darkness.

Final Word of How to Manage Light Interruptions

So, there you go! Disturbance in both the light and dark cycles can affect the growth and yield of the plant. Whatever the reason might be. It can screw up the health of your cultivar especially during its flowering stage. Besides, you have to have better knowledge, attentiveness, and as well as foreseeing the needs of your plants. You can ensure that the provision of light remains to be consistent and uninterrupted. Thus, empowering the growers to take control of the light situation.

We hope you’ve enjoyed reading this article as much as we enjoyed writing it for you! Let us know what you think in the comment section below.

Gary Stephen
Gary Stephen

Hi, I am Gary Stephen. I have been gardening for a long time. Gardening gives us much benefits and pleasure. Many of us desire to have a garden, but it cannot fulfill the desire for the proper guide or instruction of gardening. So, I am eager to help them. For this purpose, I have developed the website to make a garden with the proper guide. So, you will get me beside you if you want to know anything about gardening.