The Vegetative Stage

The most forgiving stage of the cannabis life cycle, the vegetative stage is where the final size and shape of the cannabis plant is determined.

When Does the Vegetative Stage Start?

While there is no exact timeline for this, the easiest way to tell is by how fast the new growth above the soil is growing. In the seedling stage, the plant is setting up the groundwork for the rest of its life cycle, so most of its focus is spent on creating roots to support the rest of the plant while getting most of its energy from the cotyledon, the first 2 round leaves that sprout from the plant. It is the reason why initially, the above-ground growth will grow at a snail's pace. Once the roots are established, the plant is able to get in more water and nutrients. With all these newfound resources, it can focus on above-ground growth. So, when the plant starts to grow at a faster pace with the first set of true leaves well developed and the next set of leaves already on the way, then you are in the vegetative stage. Generally, this takes about 2 to 3 weeks starting with seeds.

What to Do in the Vegetative Stage

At this point, to support the vigorous new growth, you will need to start supplementing with a grow fertilizer high in nitrogen if you are not growing with fertilized soil. Nitrogen supports stem and leaf growth, so it is vital to ensure that the plant is growing at its full potential. With that said, never over-fertilize a plant as excess nutrients will not help a plant grow faster, and nutrient toxicity will actually slow a plant's growth. A good rule to follow in the vegetative stage is to feed your plants with 50% of the dosage your fertilizer of choice recommends and to stay at 50% unless the plant shows signs of a nutrient deficiency, and only then should you increase the amount of nutrients given to the plant as it is much easier to give a plant more nutrients if needed then to try and correct overfeeding.

Also, since the plant will be focusing on stem and leaf growth in the vegetative stage, this is the time to do training techniques that involve affecting how the plant grows. Topping, low-stress training, and anything else that could stunt a plant’s growth should all be done during the vegetative stage. The new growth on a plant is still flexible and easy to manipulate and any technique that slows or stunts the growth of the plant can easily be mitigated by just leaving the plant in the vegetative stage for a bit longer.

The 4 Plants Are All In The Vegetative Stage And Each Can Be Switched To The Flowering Stage Anytime Based On Space / Time Constraints

Any mistakes made so far, as well as any plant problems occurring, should also be corrected during the vegetative stage. Any issues, from nutrient and watering problems to bugs eating parts of the plant, need to be fixed before switching to the flowering stage. The plant is constantly producing new growth, so any older leaves that get damaged or destroyed can be mitigated with the growth of new leaves and stems. Also, because the flowers and buds haven’t started to develop yet, you can still use certain pest control measures on the entire plant that you cannot use when the plant flowers. Finally, any mistakes made in the vegetative stage that slow down the plant growth can easily be made up by extending the vegetative stage by a few days, which can't be done in the flowering stage as there is a fixed timeline for the buds to development once flowering starts.

Switching to the Flowering Stage

The minimum a plant should be in the vegetative stage is at least a week or two, but other than that, the only two constraints when deciding when to flower are time and space. You must decide how much time you want your grow to take and how large the plant can get before it is too big for your grow space.

Depending on if you are doing an indoor or outdoor grow, the constraints are usually the opposite of each other. Typically, for indoor grows, the problem is space. Since you have full control of the light cycles, the key is to make sure the plant does not outgrow your grow space. Typically, indica-heavy strains will grow another 50−100% in height in the flowering stage, and sativa-heavy strains can double or more in height in the flowering stage. This “final stretch” at the beginning of the flowering stage is unavoidable, so be sure to keep it in mind when deciding when to flower.

Let us take, for example, a four-foot tall grow tent using LED lights that requires a grow distance of one foot from the top of the plant. That gives us 3 feet to work with, and if the pot and soil take up a foot of space, now we are down to 2 feet left for the plant to grow. In this scenario, you would want to start flowering when the plant is about one foot in height if it is an indica-heavy strain and possibly even sooner if it is a sativa-heavy strain. If that doesn’t sound like a lot of space to work with, this is why training techniques are important when growing indoors, While most indoor setups are limited by height, there is typically more open space horizontally for the plant to stretch out. So, by using techniques to have the plant spread out horizontally, not only are you increasing the plant’s size, but this also utilizes more of the light that would otherwise have been wasted if it hits the floor instead.

For outdoor grows, the constraint is typically time. Since you can not control when the grow season begins and ends, you will need to plan the start of your grow based on the amount of daylight per day and then let it switch to flower on its own once the daytime gets shorter in the fall and winter months. While there are ways to manipulate the time spent in the vegetative stage for outdoor grows by utilizing grow lights, this is typically more common for commercial grows due to the costs involved with doing so. Additionally, as long as you live in an area that allows you to start your grow in the spring and harvest in the fall, your plants can easily reach 6 feet tall or more on their own from the months-long vegetative stage. Of course, if you do not want 6-foot tall plants, you can always start the grow later in the summer to shorten the vegetative stage or utilize some form of training technique to keep the plant’s height in check.

Also note that almost none of this applies if you are starting with an automatic seed, which will flower automatically based on a strict timeline.

What to Do in the Vegetative Stage - Automatic Seed Edition

Timeline wise automatic plants will typically only stay in the vegetative stage for a few weeks, and the main focus during this cycle is to keep the plant as healthy as possible since there is no extra time available to let the plant recover from any issues that might stunt its growth. Due to this, any sort of training technique that could delay the growth of the plant is not recommended, although low-stress training is ok as this technique won’t slow the plant’s growth rate.

Did this guide help? This article was taken directly from The Absolute Beginner's Guide to Growing Cannabis book, so if you like the advice above you'll love the rest of the book, which includes a lot of exclusive content not found anywhere else. You can find both the e-book and paperback copy on Amazon, and it's free with a Kindle Unlimited subscription!