In this section of our three part series on growing cannabis we discuss the best growing practices for cannabis during the cannabis vegetative stage of growth. This stage of growth is important to have healthy cannabis growth, before the plants start to flower. In order to grow the largest buds possible, growers will need to trim, train and grow the largest plant possible before switching their vegetative cannabis plants into the flowering stage which will be our next section in this article series.
When is the Cannabis Vegetative Stage of Growth?
Once your cannabis has its first true set of leaves, your plant is not considered to be in the seedling stage of growing anymore. The cannabis plant will start to grow larger leaves with more leaf blades on each set of leaves. Now until the time that you place the plant under 12 hours of darkness for each 24 hours of day, your plants will grow in the cannabis vegetative stage of growth.
How long is the Cannabis Vegetative Stage of Growth?
This stage of cannabis growth can last as long as the grower likes indoors where they have control of the lights. As long as the plant is not receiving 12 hours of darkness per day it will continue to grow in this stage until the grower changes the lighting for it to start flowering. Outdoors this happens when the days start to get shorter in the late summer and early fall. The vegetative stage tends to be from Middle June till Middle August depending on where you live in the world.
Some growers, when using a “mother plant” will keep their plants in the vegetative stage indefinitely. They will leave them growing like this for years, taking cannabis clones from this plant to create more plants to grow and flowers that will be identical to the mother plant left in vegetative growing. If you would like to learn more about growing mother plants and cloning we recommend reading this article.
Caring for your plant in the Cannabis Vegetative Stage of Growth
Now that your plant is now longer in the seedling stage of growth it’s time to start adding more nutrients to keep your plant growing strong and healthy in the next stage of its life cycle. Now that your plant has started to grow full sets of leaves it will need more water and more nitrogen to keep it growing green and healthy. As the plant grows bigger it will also start to grow faster, this is because it is growing more and larger leaves. As they grow bigger the leaves are able to use more energy from the grow lighting or the sun.
Moving your Cannabis Plant to a Larger Container
Now that the plant is growing larger and faster it is time to transplant the plant into a bigger container. Cannabis needs a large root system to grow larger buds so this is a very important step. You don’t want the plant to become rootbound once it moves into the next growing stage, flowering. This will cause numerous growing issues including slow plant growth, and smaller buds. The plant should have the same amount of root growth under the plant as vegetative growth above the plant.
Making sure the roots have lots of room to expand is very important throughout the entire vegetative cannabis growth stage. We recommend using 5 to 7 gallon containers for this stage of growth, you can also use the same containers for flowering as well.
How to Transplant for the Cannabis Vegetative Stage
Remove the plant from its smaller container that was used in the seedling stage of growth. Tap on the pot to slowly release the plant from the container being careful not to damage the root ball. Once it is released from the smaller cannabis container, place the root ball in the new pot and back fill the soil or medium you are using around the plant’s root ball. Press down gently around the roots to lightly compact the soil. Once you have finished transplanting the small plant, water around the top of the soil. This will help the roots start to move into the new medium, and you will give a bit of a growth spurt once the new roots get established.
Cannabis Vegetative Stage Lighting
Once the plant has hit the full vegetative stage it is ready to be moved into the full sunshine or higher amounts of grow lights. Typically growers will give less lighting to seedlings but now that that stage of growth is completed the plant can now use more intense light.
Is 16 hours of light for Vegetative Growth?
This is normally what growers will set their timers at when keeping their plants in this stage. However there is no real drawback that we have ever experienced growing plants in vegetative stage with 24 hours of lighting. In fact we feel that the plants will grow faster under 24 hours of lighting. This will actually get your plants to the flowering stage even faster than 16 hours of light per day. Of course this will increase your monthly power bill so it is in fact a trade off of sorts.
How high should lights be in vegetative stage?
Normally when growing for personal use it is a good idea to keep the plants lighting about 18 inches from the top of the plants if you are using LED cannabis lighting. It’s always a good idea to keep your plants as close to the grow lights as you can without burning the top growing shoots of the plant. If you are able to place your hand under the lighting for a couple of minutes and your hand does not get warm then your lighting is just at the right height.
The last thing you want when growing cannabis under grow lights is to burn the growing tips of your plants. The growing tips are very important to your plants.
Cannabis Vegetative Stage Feeding
There are many different ways to feed cannabis in the vegetative stage depending on how you have chosen to grow your plants, either organic soil, hydroponic, or soiless. Most growers have less issues with cannabis feeding during this phase of cannabis growth.
However one issue that many growers run into is nitrogen deficiency. This happens when the plant is lacking enough nitrogen from the growing medium and the grower has to supplement extra. Growers can tell when this issue is present by checking the bottom leaves of the plant. These leaves will start to turn yellow, as the plant takes the nitrogen from them to move it to the upper, more important growth of the plant. If you see this happening then it is best to use some more nitrogen rich fertilizer to keep your bottom leaves green and healthy.
Best PH for Cannabis Vegetative Stage
PH for cannabis plants will be the same throughout all stages of growth. The range will change however depending on how and the type of medium you are using to grow your cannabis plants. For the cannabis vegetative stage in soil the PH range should be about 6.2 to about 6.7, this will allow good access to all nutrients that are needed for this stage of growth. In hydroponics it should be a somewhat lower range of 5.6 to 6.2 for this stage.
Trimming Leaves during this stage
Once your plant is growing well into the vegetative stage it is a good idea to start removing bottom branches of the plant as well as the leaves. These leaves will be receiving little growing light indoors. Outdoors this can also be done however as the sunlight is much more powerful it is somewhat less important. Once the plant is about 1 and ½ feet tall this is when it is a good idea to remove all the bottom growth from the plant. This benefits the plant by giving it more air flow above the tops of the pots.
Most of the time, the plant will be attacked from below by fungus and molds. Removing bottom growth will help prevent these issues. Under the plant where there is higher humidity, and less air movement is normally where these issues will start to grow and spread to the upper plant.
Trimming and Training Your Plants in the Cannabis Vegetative Stage
Once your plant has a few sets of leaves and branches, it is a great time to start using some training methods to get larger plants. Typically cannabis plants will grow like a medium sized christmas tree when left untrimmed. Indoors this is counterproductive, as you would like as many top growing branches to get as much light as possible before starting the flowering stage of cannabis growth. There are many ways that growers can trim plants to get the best results. One of these ways is to use the LST (Low Stress Training) method of training. We have an in depth article here that will teach you how to grow cannabis using this method.
Once your plant is ready to flower it will also need strong branches and stems to hold up your cannabis buds so they don’t break. This is also a great time to start using methods to strengthen your plant to prevent this from happening. We have an article here that can help you strengthen cannabis branches and stems.
How do you know when vegetative stage is done?
Most of the time plant height will let you know when the cannabis vegetative stage is completed. We say this because indoor your plant height is limited by the height of your grow tent or growing space that you have set up. Even when trimmed or trained a cannabis plant can grow (also referred to as “stretching”) 150% over the height it was once it starts the flowering stage of growth. This is a good indicator of when you should stop vegetative cannabis growth and move into flowering.
Growers can use this method by taking the highest height of their light. Then take the height of their growing plant and times it by 1.5 this will give you the approximate height of your fully flowered cannabis plant at harvest. The plant should still be about 18 inches from the light at harvest. So the best time to stop vegetative growth is when the plant has reached the height that it can still grow about 1.5 times the height it currently is.
How long is too long for vegetative stage?
For growers there is no real “right” answer for this question. If you have 60 foot ceilings then you can grow your plants in the vegetative stage until the plants would be tall enough to harvest at 60 feet tall. The only real correct answer to this question is when you will run out of height for your plants. When growing outdoors the stage will be dictated by the length of your growing season, once the daylight decreases to the point to insistate flowering.
Outdoors if your plant does not start flowering, there could be other reasons like street lighting or yard lights that are keeping the plant from moving into its next natural cycle of growth.
How Long before I can flower when in the Cannabis Vegetative Stage?
We recommend at least 5 weeks of full and healthy vegetative cannabis growth before starting to flower your cannabis plants indoors. Anything less than this may result in smaller yields, and the plant may also have issues starting to grow flowers in the flowering stage. You can also use cannabis “pre-flowers” to judge when the plant is ready for flowering from the vegetative growth stage.
Do you trim fan leaves during the vegetative stage?
Other than the bottom leaves of the plant there is no need to trim fan leaves until about two weeks before you switch the plant from the vegetative stage of growth to the flowering stage of growth. Removing fan leaves at this point is referred to as “defoliation” of the plant before flowering.
To do this the grower removes the upper and middle largest fan leaves from the growing plant. This helps to unblock the uppermost branches from getting the most light possible. When growing indoors under artificial lighting these leaves can cause shadows over the growing tips of the branches. When starting flowering you don’t want any shadows from the light over your flowering branches. So using defoliation techniques can help to prevent this from happening. We recommend reading this article to learn how to defoliate cannabis plants for maximum growth.
Best nutrients for Cannabis Vegetative Stage
Most hydroponic solutions will have nutrient mixes that are made specifically for growing cannabis vegetatively. You will only need to mix these nutrients as recommended by the manufacturer to get the best nutrient for this stage of growth.
When growing organically if the soil was created well beforehand you may not have to add any extra nutrients. However if you would like to then we recommend using high nitrogen organic nutrients. Some of the ones we would recommend are:
- Blood Meal
- Fish Meal
- Insect Frass
- Soluble or Liquid Seaweeds
Cannabis Vegetative Stage Temperature
Once the vegetative stage of growth begins you can lower the temperatures from the seedling stage. At this point the temperatures can be lowered to 69F (21C) to 73F (23C) for vegetative cannabis growth. Growers can increase the temperatures in the growing space if they are supplementing with C02, this will allow for higher temperatures.
Can Growers get a higher Yield with More Vegetative Growing Time?
Yes, generally the longer the plant is grown for the larger yield that plant will have. When the plants are in the cannabis vegetative stage, the longer they have time to grow the larger yield they will produce. This is because the plants have had more time to grow branches and more importantly nodes that will grow buds on each of them though the flower stage of growth. A longer growing time in this stage will also give more time to trim and train your plants to have a higher yield at harvest time.
Growing in the vegetative stage for cannabis is actually one of the easier stages to grow cannabis; it is somewhat easier to grow in this stage then either the seedling stage or the flowering stage. The plant will require slightly less light to grow, less nutrients, and there is little chance of mold or bud rot affecting the plant in this stage. The grower only needs to make sure the plant has enough nutrients, and water to get good growth overall in the cannabis vegetative stage.