The growth phase
You put the germinated seeds in the soil and after a couple of days later you see them peeping above the ground and becoming twiggy green plants. I always find that a beautiful moment. Your plants are still small and fragile, but soon they will become bigger and stronger. The growth phase is vitally important for your plant. A good growth is more important than the flowering. In the growth phase you pave the way for a good harvest and this will determine the final size and yield of the plants. So pay close attention now!
In the pregrowth phase, you let your plants grow to a certain height. In order to keep your plants in the pregrowth phase, you have to give them 18 hours light and 6 hours darkness for a certain period (from one day to a couple of weeks). The timer of the lamp needs to be set to 18/6. The plant can now fully benefit from the light and begins to grow both in width and height. The more you let the plant grow, the more leaves it will develop on the strong side branches. Thanks to these side branches, it will be growing even faster. Initially, the growth is always slow until the plant has developed enough leaves to achieve a certain growth rate. From that moment onwards, the plants can grow a lot in one day. For good pregrowth you have to constantly keep all factors under control.
The number of days of pregrowth you give to your plants depends on the amount of plants you have. The fewer plants you have, the more days of pregrowth you can give them. The idea is that the plants should utilise the entire growing room, without getting too much in the way of other plants. A cannabis plant needs space to develop side branches. If you put too many plants in one space, they will grow more in height than in width and they will not be able to develop optimally. If you have five cannabis plants per square meter, you have to give them a pregrowth period of seventeen days, although this varies per strain. The more plants you have per square meter, the less they will grow. If you have more than nine plants per square meter, this will seriously hinder growth. With 9 plants per square meter, a pregrowth of 9 to 12 days is enough.
In order to get as much as possible out of your plants, it is advisable to let them grow to a height of 60 to 70 centimetres. Do keep in mind that some strains do not grow that tall. Some cannabis strains stay small, while others grow very tall. If you buy cannabis seeds, always look at the Indica/Sativa rate. Most cannabis strains are a cross of Indica and Sativa. Indica plants tend to stay small and compact and have dense foliage. Sativa plants grow taller and have less side branches, as a result of which the foliages is less dense. The size of your plants will also depend on the wattage of your lamp. The higher the wattage, the bigger the plant will grow. If the plant is too big, the light will not be able to reach the bottom of the plant. It will not get enough light and only the top will develop well.
Different substrates offer different growth speeds. The most common substrates are soil, coco and hydro (water cultivation). Each substrate has its own qualities, advantages and disadvantages.
Soil is a perfect medium for beginning growers because it already contains nutrients and you don't have to add too many. By experimenting with soil, you will expand you growing knowledge. If you want to grow your plants in soil, you have to be careful which kind of soil you buy. The choice is abundant. You can opt for the cheap bags of soil you can find in the garden centres. It's possible to grow your plant in it, but beginners especially might experience problems with it. These types of soil do not contain enough nutrients for cannabis plants, are not light enough and dry and harden very easily. Good air permeable soil is important for the development of the roots of your cannabis plant and will allow your plant to become stronger and healthier. You can add perlite (tiny white stones) to the soil to make it lighter, but why make things more complicated than they are? I prefer to buy soil in a specialised grow shop, which can be found all over the world. There you can buy good soil that is specifically intended for growing cannabis. These high quality mixtures are light, generally thanks to the addition of perlite, and contain enough of the required nutrients. Admittedly, it's a bit more expensive. But you have to be prepared to pay more for quality. The biggest advantage of good soil is that your plant needs minimal extra care. Good soil is very important for your plant, so if you want to save money, do so on anything but the soil. If your budget really does not allow you to buy good soil, then the next best option is cutting soil. This is a more expensive type of soil mixture of better quality. In any case, don't use compost intended for flowers, because that kind of soil is usually too acidic for cannabis plants.
Suzy’s Tip: Cannabis plants do well in almost any type of soil. After all it's still a weed. But if you spoil your plant, it will spoil you in return with a beautiful and rich crop.
You can also grow your plants in coco. Coco is very light and thanks to the oxygen-rich fibres, the plant makes an excellent start. Your plants become stronger and grow more powerful side branches. The disadvantage is that coco does not contain any nutrients so you have to add liquid nutrients early on. Be careful, because there's also a risk of overfertilisation. Overfertilisation can be caused by a conglomeration of salts present in the nutrients. If you add too high a dose of nutrients, the plant will not absorb them well. The leaves will be marked with ugly stripes, dry out and die. What you can do then is rinse the medium. Luckily coco is very easy to use and hard to overfertilise.
In order to cultivate on water, you need knowledge and experience. I grew with soil and coco for years before I started with hydro. It is very important to monitor the EC and pH rates. You have to be able to read from your plant which nutrients it needs. The plant reacts directly to what you do, so there's no room for mistakes. This is really for the more experienced growers. If you know what you're doing, you can achieve a good yield with this growing method. As long as you’re doing it right, growing in water gives you the fastest growth rates. This is because of the large amount of oxygen the roots can take in. Growing in water is much more labour-intensive than growing in soil or coco, but once you have mastered the method, all will go smoothly. You will however be dependent on electrical appliances and if these falter or if there's a power cut, you will have a problem.
Almost every grower I know uses root stimulators in order to achieve a powerful growth. A small seed has few roots and you want the plant to produce as many roots as possible. A root stimulator will give the roots a growth impulse.
In order to limit the growth period of you cannabis plants, you need to ensure a proper humidity level. You can simply do this with a bucket of water or wet towels but a humidifier is most effective. With a humidistat or a thermo-humidistat, you can control the humidity level. During the growth phase, you have to maintain a high humidity level of around 80%. At this humidity level, the plants can develop very quickly and you can limit the growth phase.
Important: Stimulators may cause other plants to grow in your soil mixture. In general liquid root stimulators are used. You can get these from different nutrient manufacturers. The root stimulator has to be diluted with water. Do not use a root stimulator in combination with liquid fertilisers because these will nullify the effectiveness of the stimulator. Also do not mix the root stimulator with nutrients. Add the root stimulant in the first days of the life of the plant. You can also add beneficial (symbiotic) fungi to stimulate the development of roots. These often come in powder and have to be mixed with water.
Suzy’s Tip:If your plant has dark green leaves, this means that enough nutrients are present. If you are uncertain whether you have to add more nutrients, it is better to wait until the leaves become lighter green. Do not wait too long or the leaves will turn yellow.