“How long is the vegetative stage for marijuana?”

If you are asking this question, then that means you are already aware of the two periods of marijuana growth: the vegetative stage and the flowering stage. What may not be so clear is how long these periods should last.

There is a difference in length of these periods when growing indoors versus outdoors. In this article, we’ll explain those differences plus tackle a few other questions that commonly asked.

What is the vegetative stage of cannabis?

The vegetative stage is a period of time where the plant simply grows and grows, but remains immature. This means that during the vegetative stage, the plant will bear no fruit, no flower. The bud sites and eventual flowers develop later, during the flowering stage.

The plant enters and exits these phases according to the amount of light the plant is receiving. In an outdoor environment, the amount of light is determined by the season. Meanwhile, when growing indoors, the grower is in control of the amount of light, and thus the timing of these two periods of growth and maturity.

When does the vegetative stage begin?

The vegetative stage begins when the plant is subjected to more than 15 hours of light per day. In nature, this time period begins as the spring days lengthen into the long days of summer.

Most indoor growers prime their clones or seedlings under indirect light. These little babies do not need direct light overhead. A little bit of light in the background is fine.

After ten days or two weeks, most Indoor cultivators will then place their rooted clone or seedling under direct light for 18 hours per day, allowing it to rest for 6 hours. This begins the vegetative stage.

How long does the vegetative stage last?

When growing outdoors, the summer season dictates how long the vegetative stage will last. The plants will thrive with vegetative growth under the summer sunlight. But once the sun starts setting earlier in the day, the increased darkness will trigger the flowering period to begin.

When growing indoors, the grower can control the length of the vegetative stage by simply changing the light cycle to 12 on, 12 off. Therefore, the real question we should be asking is “how long should we allow the vegetative stage to last when growing indoors?”

How long should you keep your marijuana plants in a vegetative state?

So when it comes to vegging your plants, how long you decide is largely dependent on your overall cultivation strategy and goals.

A longer vegetation period will give you a bigger plant overall, which will ultimately result in more yield. But a longer veg takes more weeks than a short veg. If you are growing on a perpetual timeline, a longer veg will result in fewer cycles per year.

By contrast, a short veg period will result in a smaller plant being sent into flower. And a smaller plant will likely yield less. But because of the shorter veg period, you should be able to get through more cycles that year.

Other considerations would be limitations in your flowering space. If you have a height limitation due to your ceiling, or your grow tent, then a shorter vegetation period will give you a smaller plant that can be flowered under a lower ceiling or inside a tent.

You will need to keep your marijuana plant in a vegetative state for at least four weeks for optimal results 

When a clone is cut, it will take about seven to ten days for that clone to fully develop its roots.  At that point, it can be potted and considered to have begun its vegetative growth period.

We highly recommend topping your plants, to achieve a higher yield and a better shaped plant that can be trained. You should wait until your plant is at least two weeks old before topping. The plant will then need a full week to recover before you should top it again. If you top twice, that puts you at around a 5-week length of veg.

The Longer You keep a plant in a vegetative state, the bigger it will be during the flowering stage

If you keep your plant in a vegetative state for longer than five weeks, that is perfectly fine. At seven weeks, the plant will be even bigger, and will yield even more.

But you must remember that during the flowering period, the plant will eventually double or triple in height. During the post-veg stretch alone, it will double in height. So if you decide to keep your plant in veg for months, just remember that it will continue to grow during the flowering period, with explosive growth in the first couple weeks.

How Long can you Keep a plant in a vegetative stage?

Theoretically, you could keep a cannabis plant in a vegetative state forever, if you had the space. If you never turned the lights off, the plant would just keep growing (assuming its properly fed).

For example, most commercial cultivators maintain “mother plants” for the purpose of propagating clones. These mothers are often kept in a vegetative stage for long periods of time, up to a year.

Why are mother plants kept in a vegetative state? The reason is that clones cannot be taking from a mature plant. Clones can only be cut from a cannabis plant that is in a vegetative state.

Therefore, in order to maintain a genetic line for future cloning, you will need a mother plant that can remain in a vegetative state.

The key is to take clones for back up mothers, that way you can discard the plant once its size becomes untenable for your grow space.

The Benefits of Keeping a plant in a vegetative stage  

The primary benefit of keeping a plant in a vegetative state is that you can continue to cut clones from it for future cultivation. Therefore, if you have only one plant of a certain strain, you will need to keep that plant in a vegetative state if you ever want to grow it in the future.

By keeping it in veg, you can maintain it as a mom, take clones from it, and continue to grow that strain. You grow the clones up in veg, and then send them into flower. The mom stays in veg.

You can send a marijuana plant back into a vegetative state to preserve the genetics

There have been instances where a grower realizes that he just sent his last cutting of a favored strain into flower. This realization that once the plant harvests, there are no more clones, can make a person freak out!

It is possible to take a plant that has been subjected to a 12/12 light cycle and re-introduce additional light (say 18 hours or 24 hours of light) to send the plant back into a vegetative state.

It will not look pretty, but the plant will be able to survive the transition. Whatever flowering sites this plant had, will turn to rot. The plant will looked stress and possibly like its going to die. But what will emerge on those former bud sites will be green vegetative “tops.” Once you see these, you know your plant has gone back into a vegetative state. From here, you can cut new clones to perpetuate the genetic line of this plant.

In our next article, we discuss the length of the flowering period of marijuana plants.


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