Key takeaways.

  • What happens during vegetation?

    Vegetation is when most of a cannabis plant's growth will take place. It gains a lot of height during vegetation and develops lots of leaves.

  • Why is photoperiod important?

    Photoperiod is the amount of sunlight hours versus darkness hours a plant gets. It's important because as the number of dark hours begin to increase, a cannabis plant is triggered into the next stage (flowering). Therefore, cultivators have to keep the number of dark hours low to keep cannabis plants vegetating.

  • What is photosynthesis?

    Photosynthesis is the process by which plant cells use sunlight, water and carbon dioxide to produce chemical energy that the plant can use. It's the most important job for a plant during the vegetation stage.

My Supply Co. is presenting to you our Seed To Smoke Series — a series of articles about the entire life cycle of cannabis. We’re going on a journey from all the potential encapsulated in a cannabis seed to the final product that ends up in dispensaries, in your joint, and moving through your veins.

The Seed To Smoke series covers:

The life cycle of cannabis is wonderfully complex and intricate. It’s one of just a handful of dioecious plants in the world (dioecious; adjective; (of a plant or invertebrate animal) having the male and female reproductive organs in separate individuals). And to think that the entire life cycle of a cannabis plant happens in 4 - 6 months!

In the last article, we described the germination process of a seed and its journey into becoming a wee little seedling. In this article, we’re talking about vegetation and growth. It’s when the cannabis plant does most of its growing, and typically when growers take advantage of growing techniques. 

The importance of photosynthesis and photoperiod for vegetating cannabis plants

A close up of a leaf displaying veins and water droplets, a photosynthesis concept

Some growers believe that a cannabis plant is finished being a seedling when it shows its first set of true cannabis leaves. These are the palmate, fingered leaves characteristic of cannabis. In any case, vegetation starts when the plant has enough leaves to really start photosynthesizing. This is when most plant growth will occur.

Photosynthesis is how plants turn sunlight, water, and carbon dioxide into sugars for their growth and development. Certain anatomical parts of the leaf called chloroplasts are fundamental to photosynthesis, which is why most of it occurs during vegetation. 

There are really two parts to photosynthesis: there’s what happens during the light phase and there’s what happens during the dark phase. Every plant needs time to sleep, or darkness, and it’s just as important to growth as sunlight is. 

Cannabis is an annual flowering plant. That means it flowers once right before the winter comes, and disperses its seeds to wait for the following spring. It’s important to think about what happens seasonally during this process. The beginning of the cannabis life cycle enjoys deliciously warm, summer weather. But as winter approaches, it’s not just the weather that changes. It’s also the amount of sunlight. This is especially true if you live in the far north or far south of the globe, where the photoperiod changes dramatically throughout the year. In the winter, there are fewer sunlight hours than the summer. 

That logically means that during vegetation, the light phase is extremely important, as that’s what there is more of. The next stage of life - the flowering phase - spends more time in darkness. So we’re going to talk a bit about what happens in the light phase, and we’ll talk more about the dark phase in the next article about Flowering and Night-time.

Photosynthesis - the light phase.

An indoor cannabis farm under lights

As we just mentioned, vegetating cannabis plants spend a lot of time under sunlight. If they’re grown indoors, growers will typically put them under 18 hours of light (6 hours of darkness) and sometimes even 24 hours of light (0 hours of darkness).

Within a cell of a cannabis leaf, there are a number of very important structures. Arguably the most important is the chloroplast, which contains chlorophylls and proteins called PSI and PSII. Solar energy is absorbed into the leaf through the proteins and is then transferred to the chlorophylls.

Chlorophylls are what begin the cascade of chemical reactions that convert solar energy into chemical energy. Other factors are included in the process such as carbon dioxide and water. Water is absorbed through the roots of the plant, whereas carbon dioxide enters through the leaves. The final product is glucose.

Glucose is used by plants as a form of energy, but also helps to make up some of the plant's tissue such as cellulose or starch. A lot of this glucose is what humans finally end up consuming from vegetables! 

Vegetation is when growers employ growing techniques

Because of the abundance of photosynthesis that occurs during vegetation, it’s also when the most growing occurs. For that reason, growers who use growing techniques such as supercropping or lollipopping will do so during the vegetative stage, and before flowering starts. 

Growing techniques are certain methods that cultivators use to manipulate cannabis plants into growing the way they want them to. Some techniques make better use of grow space, others maximise the number of locations where a plant will produce buds, etc.

A plant will vegetate for anywhere between 2 and 8 weeks, depending on the kind of seed and the variety. How tall it will grow also depends on the variety and the growing conditions. The vegetative stage is essential to preparing the plant for flowering. If vegetative growth is unsuccessful, the ability for the plant to produce an abundance of flowers is dramatically decreased.

In our next article, we’ll be talking about Flowering and Night-time, so don’t forget to check in!

Have you ever grown cannabis? How much did your plant grow during vegetation? We’d love to hear from you in the comments!

Leave a Reply