What happens to your plants when you interrupt light cycles?

Why are some growers so paranoid about interrupting light cycles for plants?

It's a good question, and it has a lot to do with people's personal experiences in hydroponics. Most newcomers don't understand what happens to plants if a light or dark cycle gets interrupted -- for instance, if you get some unexpected visitors and need to open up the grow area and let light in during the dark cycle, or if your grow lights go out because of a power outage or other problem.

So what happens to plants? No, they won't turn into gremlins or start raiding your refrigerator -- but interrupting the light cycles for plants can lead to some pretty extreme changes. This is because plants have their own circadian rhythms, and they respond to light in certain ways.

Vegetative Versus Flowering Stages

Some growers suggest that it's less dangerous to interrupt the light cycle EARLIER in the plant’s vegetative stage than it is in the flowering stages. This has to do with how plants respond to sudden changes in light. A lot of growers use changes in a light cycle to induce flowering -- to get plants to start producing buds or clusters. So if this delicate process has been started, changing light conditions can cause things to get weird. Some growers have reported plants going back to a vegetative state, or talk about what's known as “going hermie” -- the idea that marijuana plants can experience gender changes because of their light cycle responses.

Light and Dark

There's also a consensus in some circles that it's less dangerous to interrupt a light end of a cycle than a dark one, or that sometimes you can just leave your lights on for 24 hours and reset the cycle. Again, this depends on each person's unique experience -- there are a lot of factors in how a change in a light cycle will influence plants and whether it will cause the kinds of changes that people are fearful about.

Look at forums, and you'll see an awful lot of assurance. Many growers have whimsically messed around with plant cycles or encountered huge problems in producing consistent light cycles, and they have not seen their plants suffer because of it. But there are those cases where radical light cycle changes can really mess up a grow crop. For more, check out the Dealzer web site where we have a trove of info for new growers, and forums and other resources for figuring out problems and maintaining plants for the long haul.