During the growth phase, or vegetative stage, the foundation is laid for a good flowering phase, the generative stage. The growth phase is an important period in the life cycle of your plant and has a major influence on the course of the flowering phase and the final yield.

The right light schedule, the ideal temperature and humidity, but also the nutrients and even the way of watering, contribute to good growth and an exuberant flowering at the end with a successful yield. It is good for a grower to know what is needed for optimal growth, here we'll exlain you. 

The growth phase of cannabis

When the seedling emerges above the ground after germination, the growth phase of the cannabis plant begins. The young plant begins to develop leaves. The first leaflets to unfold from the seed are the lobe leaves, then the characteristic serrated leaves that start with one "finger" form. The next leaves get more and more fingers. 

Depending on the variety and strain, as well as the conditions, cannabis plants can grow into trees several meters high. Some are short and bushy with many branches and a thick trunk. Others are thin and elongated or are a combination of both. Autoflowers will not reach great heights because they will flower on their own, but they do have a growth phase as well. The sex of a cannabis plant can only be seen when it starts to flower, so sow feminized seeds to be on the safe side.

Growth phase outdoors

Depending on the climate and the number of light hours per day, it is possible to grow your own cannabis outdoors. Sativa-dominant strains prefer a tropical climate, while a strain with a heavy indica influence thrives in a milder climate. Therefore, make sure that the strain you want to grow is suitable for the climate where it is grown.

In mid-western Europe, August will be the start of the flowering phase of outdoor cannabis. The days are getting shorter and the plant will respond by starting its next phase.

There are strains that react faster or slower to this, causing some to flower earlier or later. So try to germinate the seeds well in advance of this period, so that the plants can fully enjoy themselves and grow into exuberant plants.

In an average climate in Europe, the advice is to start growing outdoors from mid-May. Earlier is possible by sheltering the plant from the cold and lighting it to stimulate growth, also known as pre-growth. Due to the long growing period they get with this, some strains can grow very large. A disadvantage of large plants is that strong wind or rain can cause branches to break or collapse under their own weight when they are in bloom.

Supporting the plants with sticks or wire mesh is therefore not an unnecessary luxury. By applying cultivation techniques such as topping, thieves and low stress training, you gain more control over the final shape of the plant.

Pre-growing also has an advantage if you want to darken your plants. By reducing the number of hours of light, you control when a photosensitive strain enters the flowering phase and, when growing outdoors, you can get her buds to flower in the best months of the year. If you have a greenhouse at your disposal, this is ideal for growing your plants, but make sure there is sufficient ventilation.

Growth phase Indoors

When growing indoors, you are not dependent on the season, you can arrange this and the climate yourself. This way you can harvest several times a year. It is even possible to keep a plant in a vegetative state and use it as a mother plant for cuttings. Once the seedling has emerged from the ground, it can be placed under a lamp. Be careful with the bright light and use a dimmer for the first time or hang the lamp higher above the plant. Unlike outdoors, with an indoor grow you have to deal with the dimensions of the grow room.

The plants not only grow in height, but side branches also develop. If you let the plants grow too large, the distance from the plant to the lamp will become too small, causing light or heat damage to the buds. With plants with many side branches that grow wide, make sure that the grow room does not get too crowded. When you switch to a light schedule for flowering, a plant will continue to grow for a while before flowering begins, this is called the stretching phase. How long they will continue to grow depends on which strain you grow. Some strains can even increase by half their height and width. So don't let them get too big.

It is difficult to say exactly how long a growth phase of cannabis plants should be, but in a grow room with an area of one square meter you can maintain the following: a growth period of 1 to 2 weeks for 9 plants and 3 to 6 weeks for 4 plants. If you grow the same varieties more often, you will gain more and more experience and insight into the development of the plant.

Try to grow the plant to a height of 60 to 90 centimeters when it is in bloom. For an efficient cultivation, try to create an even canopy. This means growing as many buds as possible at the same height. To achieve this, cultivation techniques such as SOG (Sea Of Green) and SCROG (SCReen Of Green) can be used.

Suzy’s Tip: With an indoor grow, the yield does not always depend on the size of the plants. Plants that are too large will smother each other and their buds will not get the optimal light, resulting in a lower yield than expected.

Growing medium

The growing medium in which you grow the plant affects the speed of growth. The most common substrates for growing cannabis are soil, coco and hydro. Each surface has its own qualities, advantages and disadvantages. Every grower has his preference.

Soil

Soil is a perfect medium for novice growers because it contains nutrients on its own so you don't need to feed as much. By experimenting with soil, you expand your growing knowledge. If you want to grow your plants in soil, you should pay close attention to the type of soil you buy.

There is an enormous amount of choice. You have cheap bags of soil, such as those sold in garden centers. In principle, you can grow your plant in this, but this can cause a lot of problems, especially for beginners. This soil does not contain enough nutrients for a cannabis plant, is not airy enough and quickly becomes hard and dry.

Good air-permeable soil is important for the development of the roots of your cannabis plant and with this soil the plant will grow more vigorous, healthier and stronger. You can add perlite (small, white stones) to the soil, which makes the soil more airy, but personally I would think: why make it difficult when it can also be done easily?

I prefer to buy soil in a specialized grow shop, which you can find all over the world. Here you can buy good soil intended for growing a cannabis plant. These high quality soil mixes are airy, usually because perlite has been mixed in, and contain enough of the necessary nutrients. It may cost a little more, but I'm happy to pay for quality. The biggest advantage of good soil is that your plant needs little extra attention.

Soil is very important to your plant, so if you want to save money, do it on everything but the soil. If your budget really does not allow you to buy good soil, it is best to buy cutting soil. This is the most expensive among regular soil mixes, but of the best quality. In any case, do not use compost used for growing flowers, as this soil is usually too acidic for a cannabis plant.

Coco Coir

Coco coir is an oxygen-rich fiber that you can use to grow exuberant plants. An experienced grower harvests more with a cultivation on coconut. Because it is a neutral medium, you will have to add liquid nutrients yourself. By doing this at the right time and in the right amount, you get maximum yield from the plant. Herein lies the disadvantage. If you give the young plant too little or too much nutrition, this can have serious consequences for the rest of the growth and flowering of the plant.

Suzy’s Tip: If your plant has deep green leaves, this is a sign that it has enough nutrients. If you're not sure if you need to give your plant more food, wait until the leaves turn a lighter green before adding nutrients. Don't wait too long either, because then the leaves will turn yellow.

Hydroponic

To grow with a hydro growing system you need some knowledge and experience. First start growing on soil or coco before you start hydro growing. You must, as it were, be able to read the plant and know which nutrients it needs.

It is necessary to maintain the EC and pH values. The plant reacts immediately to what you do and you cannot make any big mistakes. So this is really for the more experienced grower. However, if you know what you are doing, you can achieve a good yield with this growing method. Growing with a hydro system will give you the fastest growth rates, as long as you do it right. This is due to the large amount of oxygen available to the roots.

Light cycle of the growth phase

Aside from autoflowers, cannabis plants will grow in as little as 14 hours of light and 10 hours of darkness. This is not really optimal, the plants can stagnate in growth or stress, but it is possible. To prevent this, it is best to use 18 hours of light and 6 hours of darkness. This gives the plant long enough light for optimal growth without risks.

At night, during the dark period, the plant produces flowering hormones and 6 hours of darkness is too little for the plant to produce those hormones and actually switch to the flowering phase. For an autoflower this is a different story and the 18/6 light schedule is even ideal for the entire life cycle of the plant. With mother plants, a light schedule of 20/4 is more often used to speed up the production of cuttings. The cuttings are then continuously under the lamp for the first few days to root extra quickly.

Irrigation in the growing period

Cannabis likes a nice moist environment during growth, but doesn't like having wet feet. You do not necessarily need an expensive humidifier, with a bowl of water or a few wet cloths you can quickly increase the humidity in the grow room. Watering is best done as carefully as possible, especially in the beginning. Water as little as possible, but do not allow the medium to dry out. If you grow in a pot you can lift it to feel how heavy it is. The heavier the pot, the moister the medium will be.

A medium that is too moist inhibits the growth of the root system, the roots are not stimulated to look for moisture, so they grow less. By watering at the edge of the pot and not at the trunk, you also stimulate the roots to grow towards it.

Check the plant, medium and humidity daily and water as needed. It is better to give a small amount of water several times than a lot at once. Make sure the water is at the right temperature and water the plant with a watering can. Young seedlings in small pots are still delicate, so moisten them with a plant sprayer and check them every day.

Conditions during the growth phase

Nutrients

Nitrogen, Phosphorus and Potassium (N-P-K) are the components of cannabis nutrients. For nutrition for the growth phase of cannabis plants, it is recommended to maintain an N-P-K ratio of 2-1-1, 2-1-2, 3-1-3. Using a root stimulator can work very well, but pay attention to the manufacturer's instructions.

PH value

The acidity is expressed in pH. This influences the form of the nutrients present in the medium. A good soil pH is between 6 and 6.5. With hydro this is between 5.5 and 6.0.

EC Value

EC is a conductivity value and indicates when the plant absorbs the maximum amount of water and nutrients. This value is different in every life phase of the plant. Start with a young seedling with an EC value of 1.2. You can gradually increase this to 1.6 during the growth phase.

Temperature

The ideal temperature for growing a cannabis plant is between 21 and 28 degrees Celsius. Temperatures may be slightly lower at night, between 17 and 23 degrees. As long as the difference in temperature between day and night is not too great. It is best to keep the temperature of the (feeding) water around 20°.

Humidity

Maintain high humidity during growth, so they can develop quickly and keep the growing period short. A humidity above 60% is perfect. For cuttings and young seedlings even up to 80%.

Ventilation

Ventilation is a necessity to provide sufficient fresh air to the growing plant. The plant extracts carbon dioxide CO2 from the air and uses it to convert light into energy for the plant, this is called photosynthesis. The oxygen that remains after this process is exhaled by the plant. And a small fan that moves the plant ensures a thick, healthy trunk.