cannabis veg time

Cannabis Veg Cycle by Dr. Robb

Dr. Robb explains why it can be helpful to put your cannabis plant through a veg cycle in his his cultivation blog.

Cannabis Veg Cycle

The technique of vegging out your cannabis crops is widely used to increase the overall plant infrastructure to support much higher yields during harvest. Your plants may have to go through the cannabis veg cycle before having to work extra hard to produce flowers. The cannabis veg cycle helps by building out their root and shoot system so that they’re ready for the rigors of high-intensity flower production. There are plants whose vegging out can be controlled, called photoperiodic, by providing them with short periods of darkness. Lucky for us, most commercially grown cannabis cultivars (or strains) are photoperiodic, which gives us more control over our crops.

Photo credit to @republicofcanna (Instagram)

Why It’s Called The Cannabis Veg Cycle?

This period of growth of the plant is called the veg cycle, or vegetative. In the world of multicellular organisms, there are two types of cells: reproductive or somatic cells (also called vegetal or vegetative cells). A somatic cell is not involved with reproduction. In order to keep your plant in the cannabis veg cycle, you have to prevent it from developing flowers. In other words, you have to keep it from developing its reproductive parts; hence, you keep it vegetative.

Why Is It Important To Veg Your Cannabis Crop Before Setting It To Flower?

The key term to that question is the word ‘flower’. As cannabis growers, we want our plants to produce lots and lots of flowers. The flower buds (yes, that is why it’s called bud) are born on the terminal tip of either the main branch or axillary branches. Those axillary branches tend to stay dormant as long as the apex of the main branch remains. As long as the tip of the main branch is still attached to the plant, the axillary buds won’t turn into new branches and will create new places for flowers to grow. Since we’re in the flower growing business, we generally want more flowers.

During the cannabis veg cycle, a grower can pinch off the apex of the main branch and break apical dominance, also known as topping. Topping will stimulate the previously dormant axillary buds to grow and eventually become more locations for flowers to develop. In addition to creating more budding branches, topping also allows for the cultivator to keep his or her plants fairly uniform in height. Achieving uniformity in production is one of the primary goals of large-scale production. It allows for more predictability come harvest. Also, if you’ve found a cultivar that is absolutely amazing and works for you and your patients, you definitely will want to get the same results time after ti me after time.

Now That We Know Why It’s Called The Veg Cycle, How Do We Do It?

Earlier, I mentioned that there are some plants that are photoperiodic. Most commercially grown cannabis cultivars are as well . First, let’s dissect that word: photoperiod. There are two base words there. Photo refers to light, and period refers to a period of time. The length of day/light, not the length of night/dark periods, dictates the photoperiodic cycles. Photoperiodic plants such as cannabis use long, uninterrupted periods of dark to pull them out of a vegetative state.

There are different types of plants that trigger flowering at different times of year, though. Irises flower in the summer and are called long day plants. Cannabis flowers in the fall, (and spring, if temperatures aren’t too cold through a winter climate) they called short-day plants. In order to continue through the cannabis veg cycle, a farmer can either keep the nighttime short or interrupt the nighttime with light. For more information on how much light to provide, visit our blog post on creating the grow room.

Photo credit to @honeydew_farms (Instagram)

Are There Reasons Why I Wouldn’t Want To Put My Crop Through The Cannabis Veg Cycle?

Actually, yes. It depends on the style growing you would like to do. Typically, a cannabis cultivator who is growing in controlled environments (indoors or greenhouse) will veg their crops from anywhere from 5 days to a couple of months. This is very much cultivar dependent. We typically veg our OG Kush phenos for 5 days. They don’t need much time. I’ve seen growers who love to veg for long periods of time even for indoor production. (Outdoor production with 1 harvest per season sees those monster trees that produce upwards of 12 lbs. per plant because they veg for many months in the open sun).

There’s a style of production called Sea of Green (SoG) where the farmer doesn’t veg much, if at all, but plants many more cuttings. Instead of increasing the number of flower sites by topping vegged plants, the farmer eliminates that step by just planting very densely with significantly more clones. SoG requires little maintenance once you set the plants to flower. You can almost plant the SoG crop and show up 2 months later for harvest. The dense foliage doesn’t really require much pruning, and all of the flowers will be tops. These plants, sometimes called “lollipops” or “bangers,” are another very viable way to produce cannabis on a large scale. It definitely saves on labor.

Additionally, there are some farmers who prefer to grow cannabis cultivars that are autoflowering (day-neutral plants). This means that the length of day or night will have little effect on when the plant flowers. Although the crop still goes through a veg cycle, the farmer is not triggering when that happens. This means that the farmer could potentially give the crop over 12 hours of light per day and potentially get higher yields. Unfortunately, the cultivars of cannabis that are autoflowering are derived from C. ruderalis , which is the species of cannabis that doesn’t produce much in the way of cannabinoids. This makes it a bit more difficult to source genetics that has both high cannabinoid content that also autoflowers as the breeder needs to breed that cannabinoid production back into the genetics. That doesn’t mean that genetics don’t exist though.

Final Words.

Vegging of cannabis crops continues to be widely used to increase the overall plant infrastructure to support much higher yields during harvest. This is the stage where our babies graduate to teenagers (yes, that is what we vernacularly refer to our plants). Unless you’re growing Sea of Green, vegging the plants really is the fundamental stage of the plant’s life cycle that promotes the foundation for a stronger, healthier harvest. Hopefully, now you know a little more about the etymology, reasons why, and basics of how to navigate the cannabis veg cycle. Although there are many ways to veg out your plants, it really depends on how you want to grow and what cultivar you want to grow.

Next month, I will be talking about the next stage of the plant’s cycle: flowering, or as I like to call it, Breaking Bud. Make sure that you are signed up for our Newsletter to be updated when the next topic is posted. Also, if you are looking for more ways to increase your yields this season, check out Dark Heart’s blog topic on boosting your yield.

(For more info about Dr. Robb visit his website)

The Schedule For The 9-Part Series

Part 1 – Introduction: Meet Dr. Robb (June 19)

Part 2 – Cannabis Veg Cycle (July 17)

Part 3 – Flower (Aug 21)

Part 4 – Harvest (Sep 18)

Part 5 – Dry and Cure (Oct 16)

Part 6 – Trimming (Nov 20)

Part 7 – Assembly Required (Dec 18)

Part 8 – Maintaining Mom’s and Genetics (Jan 15)

The cannabis veg cycle is widely used to increase the overall plant infrastructure to support much higher yields during harvest.

When To Switch Your Cannabis Grow From Vegetative To Flowering

When switching cannabis plants from the vegetative stage to the flowering stage, growers need to be aware of numerous considerations. Making the switch at the right time is crucial to maximising yield and avoiding complications.

Knowing when to flip your grow from the vegetative to the flowering stage is one of the most important factors to ensure the success of your plants. This is because making the switch too early can result in a smaller total yield. Conversely, making the switch too late can result in overgrowth, or burned buds. The decision to make the switch should be based on the careful consideration of numerous factors such as the age of the plant, the maximum height that the plant can obtain within your setup, the type of strain(s) being grown, the source of the plant (from seed or clone), and the growing method being employed.

When making the switch, growers need to be aware of all of these conditions, and of the ways in which they can affect the final product. Since each grow is unique, growers should be careful when copying the methods and techniques used by others. They may actually end up giving you dramatically different results than what you intended.


Sort of—not really. Some growers believe that plants grown from seeds must be given 60 days of maturation in the vegetative state. However, this is not necessarily true. It is important to remember that young seedlings cannot start properly flowering for 2–3 weeks. However, when growing from clones, age is not an issue. Growers can switch to the flowering stage as soon as the clone has established a solid root system.

In optimal conditions, plants should be kept in their vegetative stage for approximately 60 days. This time period should give the plant the opportunity to maximise yield and acclimatise to growing conditions. This is important because complications and mistakes are much more difficult to recover from during the flowering stage. It should be noted that this time period is just a recommendation. If maximum yield is not a priority, or if growing conditions will not permit for a lengthy vegetative stage, plants can be flowered long before the 60-day benchmark.


The most important consideration is the amount of space available for your plants. The longer that plants are kept in a vegetative state, the taller they will become. As such, vegging your plants for too long in a confined space can result in an overgrow situation. Plants that grow too high can potentially reach too close to light fixtures and suffer damage as a result. Ideally, you should never let your plants reach closer than 30cm from the lights above them. This is a rough estimate. However, growers risk burning or frying their buds if they allow them to reach any closer.

Be sure to consider the light fixtures being used in the grow. Some bulbs glow hotter than others, and this will certainly affect the minimum distance that should be kept between the plants and the lights. How long you let your plants grow in their vegetative state should also depend on the kind of strain that you are growing.


The genetic differences between indica and sativa strains must be considered when making the switch to the flowering stage. That is because indicas and sativas behave differently during flowering. Indica strains are known for producing shorter, thicker, bushier plants when compared to their sativa counterparts. Typically, they will gain only 25–50% of their height in the flowering stage. By comparison, sativas are known for their height, and for their ability to keep growing taller throughout the flowering stage. They have been known to double their height from the first day of flowering until harvest.

Keep in mind that these characteristics apply to pure sativa and indica strains. Most strains will demonstrate characteristics representative of both kinds since they are not 100% indica or sativa. When dealing with hybrids, make sure to research the genetic makeup of the plant so as to have a better idea of what to expect during the grow. A basic rule of thumb for growing hybrids is to expect that the plant will grow to be twice the height it is at the end of its vegetative state.


The planting method chosen for the grow will also affect the timing of the switch. The difference between growing from seeds or clones will affect the growth rate of the plant’s root system. If the plant has not established a solid root system, then there may be issues and complications during the flowering stage.

Clones can grow very tall very quickly, forcing growers to make the flip to flowering based on plant size alone. However, growers should make sure to give their clones the necessary amount of time to establish themselves before flowering. Seedlings can be flowered much earlier, but remember that they will require 2–3 weeks before being able to do so.


Different growing methods such as the sea of green (SOG) method, the screen of green (ScrOG) method, lollipopping, and super cropping can all affect the switch. Depending on which method you choose, your flowering time will likely be different.

  • Sea of Green (SOG)

This method relies on flowering plants early so that they only produce one large bud. This method is usually employed with indica strains that are packed tightly together in the grow space. When using this method, plants should be flowered when they reach a height of between 15–30cm.

  • Screen of Green (ScrOG)

This method utilises a mesh screen that is layered horizontally above the plants. The screen is typically placed 30–60cm above the base of the plants. This allows them to grow right through it. When using this method, plants must remain in a vegetative state for several more weeks than with the SOG method.

  • Lollipopping

Lollipopping is a technique that involves removing the lower growth of the plant that receives very little to no light. Because plants need light to grow, these regions will produce smaller buds and drain the plant of energy that could be better spent elsewhere. By removing the lower leaves and bud sites, the plant can focus its energy on the upper colas that grow denser, thicker nugs. This method typically involves a height-based flowering switch. Sativas are usually switched when they reach 30–45cm, since they grow so much during the flowering stage. Indicas are switched when they reach a height of around 100cm, giving them more time in the vegetative state.

  • Super Cropping

This method is designed to produce very heavy yields from a minimal number of plants. As such, plants grown using this technique need to remain in the vegetative stage for longer. Super cropping involves bending upper branches down so as to allow more light to reach the lower parts of the plant. This keeps the height of the plant in check throughout the grow, and allows for a longer vegetative period.


Typically, outdoor growers allow their plants to flower by themselves. This usually occurs after mid-summer when days become shorter than 12 hours. Outdoor growers should take care to ensure that their plants do not receive any kind of light at night. This includes light sources such as garden lights, street lights, or spotlights.

However, outdoor plants do not necessarily need to be left to their own devices. Similarly to indoor plants, they can also be forced to flower by a change in conditions. Some climates simply do not offer plants enough time to flower before winter. Other climates may require a grower to force flowering so as to keep the plant in check. Additionally, some growers choose to force flowering in order to harvest multiple grows during the same season.

Whatever the reason, forcing outdoor plants to flower is a simple process. Outdoor growers usually force flowering by covering up their plants, reducing their exposure to sunlight as a result. Cultivators using greenhouses simply need to cover the windows of their grow room.


For most cannabis strains, the flowering period will last somewhere between 7 to 10 weeks. What happens during this period will vary from week to week and strain to strain. For more information about what you can expect during the flowering period, check out the week-by-week Royal Queen Seeds flowering guide.

Switching your cannabis plants from the vegetative stage to the flowering stage requires careful consideration of several important factors.