How to Veg and Prune Your Cannabis Plants

By: Vitaly Deanman

When you are growing marijuana indoors, there are a lot of things that you have to consider. A large part of that is handling the two stages of growth: vegetative and budding. The vegetative phase is incredibly important, given that this is when your plants will build up their root systems and build strength that will carry them through the time of carrying heavy flowers, or buds. If you take care of vegetation right, you’ll have nothing to worry about once your plants start budding.

The Right Light

During the vegetative stage of growth, the light that you provide your plants with is incredibly important. That means choosing the right light for the job, which is usually LED. LED grow lights are going to give your plants the entire spectrum, without leaving out the all important blue light. HPS lights, by comparison, only have around 3% blue light. That is not near enough to get your plants stretching in the right way.

How Much Light Is Necessary?

The question of how much light your plants need isn’t exactly an easy one, but with the right information you can make the right choice. All of this depends on the amount of space between your plants, the genetics, the conditions of the room, and more, so pay attention to everything that is going on in your grow room before you start purchasing lights. What is important for vegetative growth, and some would say more important than the amount of lights in total, is that your plants need to have light shining on them for 16 to 20 hours every single day. This replicates the long days of the summer that the marijuana plants would typically be getting in ideal outdoor conditions.

Feeding Your Plants The Right Nutrients

Nutrients are just as important as light. If your plants have plenty of light, but nothing to use for energy to grow, they are going to stutter and fail. It can be a complicated issue if you want it to be, but there are a large number of pre-mixed batches of nutrients that you can use. These are also made especially for different stages of growth, further simplifying the process greatly.

These nutrient mixes are primarily made using three things: Nitrogen, Phosphorus, and Potassium. With different combinations of these three nutrients, you can easily provide your plants with whatever they need, regardless of the stage of growth that they are in. There are also micronutrients, such as Calcium, Magnesium, Sulfur, Manganese, Boron, Zinc, Iron, Molybdenum, Chlorine, and Copper.

During the vegetative stage, though, the general rule is that the ratio of the three primary nutrients, N:P:K is 2:1:1, since Nitrogen is most important during this stage. You should not, however, start off at the full feeding schedule, since you will overwhelm the plants. To start with, begin using 25%-50% dilution until you have worked all the way up to 100%.

That helps prevent the ever-growing problem of over-fertilization. Plants need nutrients, so why not give them a lot of them? The problem is that this will actually “burn” your marijuana plants, turning them brown in the process. If you happen to notice that this is starting to be a problem, you should immediately cut back on the amount of nutrients that you are using. If you slowly ramp up the nutrient levels, however, this shouldn’t be a problem for you. Every strain reacts differently to different levels of nutrients, meaning you will have to pay attention during this crucial stage.

Pruning and Shaping Your Plants

There are plenty of ways to prune your plants or otherwise shape them, but a few things stand out if you want to have the most success. When it comes down to it, depending on what you are looking for and how much experience you have you can do a lot to make your plants better suited to the task of growing indoors.

Removing Leaves

The leaves of your plants are what are going to be producing the sugar. The insides of the leaves are going to bring in the CO2 and create energy for your plant, but they can also get in the way. Once the leaves are fully formed, they stop producing energy and can be clipped away, although this isn’t ideal for the vegetative stage of growth. it is nonetheless important to having healthy plants, which is what this article is all about.

This is how you get the Christmas tree shaped plants, creating plants that have a “bed” of buds that don’t have all of those pesky leaves that you aren’t going to be able to use anyway. To do this, simply trim the fan leaves when they begin cramping the growth and turn yellow. Do not clip off the tiny shoots that are forming new colas, though.


Topping a plant is best done when it only has 3-5 nodes in all, or sets of leaves. Basically, you are going to cut off the newest nodes that are growing off of the main cola, just above the leaves of the second node. Effectively this will turn your plant into bushy ones that grow mainly buds. These two colas that are formed are going to spread apart and make it possible to send much more energy to the buds, instead of spending it trying to keep a large number of leaves alive.

You’ll also notice that the lower branches will start to grow buds and rise up to meet the canopy, creating a sea of buds that you can harvest at the end of the budding stage. Taking care of this during vegetation will set you up for success, so don’t miss out on it.


Trellising will limit the height of your plants during the vegetative stage, without having to prune anything from the main stem. In fact, it is much like the way that people typically grow grapes.

To do this, insert posts into the ground that are one to three meters apart, with horizontal wires at around 25cm intervals. The idea is that the marijuana is going to grow in between the posts and they will be bent to fit the wires as they grow. This trains the limbs of the plant to grow horizontally, instead of vertically, so that they will be able to get the maximum amount of light without having to trim them extensively.

This is most useful for outdoor growing, but it is possible to do it indoors. That is why so many people turn to a relative of trellising known as Screen of Green.

Screen of Green (SCROG)

Screen of Green is the best way to grow bushy plants indoors during the vegetative stage especially. When the plants are 15cm tall, you are going to begin training your plants to grow against a chicken wire framework, or something similar. As the vegetative stage of growth continues, your plants are going to stretch out and continue to grow, but they will all be at the same height, giving them perfect access to light as well as making them incredibly easy to manage.

Depending on the amount of space that you have available, you might choose a different way of pruning or training your plants. Many people swear by screen of green systems for indoor grows, though. The ability to create a dense canopy of buds is something that makes grows extremely profitable as well as easy to take care of.

When To Make The Switch To Budding?

If you have taken care of the plants during the vegetative stage, you’ll be well on your way to a healthy harvest and have some strong plants on your hands. They will be ready for the heavy buds that are going to start growing on them, so when they are ready it will be time to make the switch to budding.

There is no solid answer for when the right time is. That doesn’t mean you can’t figure it out, though, and it can largely depend on the kind of plants that you are trying to grow, whether they are going to be tiny shrubby plants or large trees resembling outdoor plants.

You should know that the plants are going to keep growing after they have entered the budding stage. If you are tight on space, it is important that you make the switch before they have stretched beyond your means. The general rule is that indices are going to almost double their height, while a salvia plant is going to nearly triple in size once it has finished budding. For example, if your lights have to be at least 12” from the tops of your plants, leaving you have 64” of vertical grow space, you should switch to budding at around 20” for a salvia plant. This kind of math can help you save a lot of hassle in the long run.

The Ever-Important Vegetative Stage

There is nothing that will make the vegetative stage unimportant, no matter what kind of advances are made in growing indoor marijuana. If you are going to have healthy harvests, it all starts here. Your germinated plants are going to be ready to start stretching once you give them 20 hours of light a day and the space to grow, so be prepared, keep an eye on the plants, and prune them into the right form so that you can have the most incredible harvests of your life.

Source: Marijuana Vegetative Growth and How To Prune Marijuana Plants

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