Marijuana plants in growth

Philosopher Seeds shows you in this post the correct parameters for optimal growth of cannabis plants both indoors and outdoors, and the suitable types of growth for your growing space and medium. We will talk exclusively about photoperiod plants - either regular or feminised seeds. Therefore, we will not talk about autoflowering marijuana plants since the onset of flowering period is an automatic process.

Basic tips for optimal growth of marijuana plants

The first thing you need to know before your cannabis plants enter the growth period, is that once into flowering, they will continue to grow, so you should prevent your plants from taking up too much space.

To avoid this, you should be cautious when you choose the marijuana seeds that you want to grow and the size of the pots used.

Among other things, nitrogen (N) is the most consumed element by the plant during the vegetative period, so make sure that your substrate has enough Nitrogen in solid form, i.e. worm humus, or by using liquid fertilizers.

Many fertiliser brands offer products suitable and especially formulated for the growth period of marijuana.

 Growing marijuana indoors

Indoors, the grower is responsible for deciding how long the plants will be in growth phase, forcing them to flower when changing the photoperiod.

At Philospher Seeds, we recommend you a photoperiod of 18 hours of light and 6 hours of darkness during the growth period (18/6). It is essential that you use a timer to set the desired schedule. Some growers work with 16/8 cycles, although this light cycle can induce certain strains into flowering earlier than desired.

Other factors such as lack of space in the container (lack of available substrate), lack of nutrients and an poor management of the climate could cause premature flowering.

Growing marijuana indoors is more complex than doing it outdoors, because this growth period will determine, in part, the overall height and the size of your plants. This means that depending on the lenght of the growth period more or less plants per square meter will be used. This is very important if we do not want problems related to the height of the plants at the end of flowering. If they end up too close to the light they may get burned.

In this table you have the recommended number of plants per square meter for each variety in our catalogue:

We usually advice a two-week growth period - for plants in 3.5 litre pots - before changing the photoperiod; three weeks for 7L pots, and 4 weeks for 11L pots.
Some varieties like SuperJuani and Jack el Frutero are mostly Sativa plants that tend to stretch a lot when flowering, so a shorter growth period is advised for these strains.

One of the most common problems during the growth period is that plants stretch and do not absorb nitrogen properly, and therefore their lower leaves get yellow quickly; this is due to wrong temperatures, light intensity and relative humidity.
For optimal growth of marijuana plants indoors, you should carefully monitor the climate parameters.
Cannabis plants are sensitive to temperature changes, so during the growth period we recommend a constant temperature of 24°C, both at night and during the day.
Another important factor when growing marijuana is having the correct humidity level: during the first week of growth it should be around 80-85%, and during the following weeks around 70-75%. In this way, the water demand through the roots is much lower. If you manage to keep these parameters and a correct fertilisation program rich in nitrogen, you will see your plants grow green, lush and healthy.

Light is another key factor in the growth phase. As long as you can, grow your plants with the whitest light you have, whether it is metal halide or any other type of light (Agrolite, CFL, etc.).

From our own experience, we have realised that the growth phase using sodium lamps (red spectrum) makes plants stretch and somehow blocks the absorption of nitrogen, causing lower leaves to quickly turn yellow.

The temperature of the water with which you water or fertilize your plants is also important in all phases, but it is even more important during the growth period because of the fragility of the roots, which are young and still developing.

This is why you should always have your nutrient solution at 22 degrees, which provides optimal balance between temperature and good oxygenation of the water.

Growing cannabis outdoors

Marijuana plants usually bloom outdoors when the days get shorter. The first flowers can be seen from around mid July (in the Northern Hemisphere), but it mainly depends on the variety and when you make them germinate. The sooner we plant them, the larger your plants will get. Growers usually decide when to germinate their seeds depending on the available height and space.

We recommend that you germinate cannabis seeds once the cold season is over,  in a light substrate - similar to light-mix - during the first 2 weeks of life, in pots of a capacity of 3-4 litres. When you see the roots peeking out the bottom holes of the pot, it’s time to transplant the marijuana plants into larger pots, or directly in the ground with a richer soil.

When plants are very small, protecting them is important, as some animals could step on them, tear them or eat them. To prevent potential problems, we recommend fixing up a wire around the plant - or a plastic bottle cut in half after removing the cap. This will also promote the maintenance of a constant relative humidity, causing a greenhouse effect.

Take extra care if you are using solid organic fertilizers such as blood or horn meal mixed with the soil, these products can attract insects.

For proper development of your cannabis plants, place them in a very sunny spot and just hope for the weather to be mostly dry.

 Different growth rates for different methods of cultivation

Depending on the growing space or the method used, you must prepare and mold the marijuana plants in order to avoid problems during their bloom period, when they stretch their branches.

Every grower has his/her own preferences and possibilities, this is why it is hard to give guidelines suitable to everyone, since in the same growing space some people will grow 40-50 plants in small pots with little growth, while others will only grow 9-12 plants in larger pots, which will have more branches and a longer vegetative period. This is why we only give you a global advice here, so you can decide which method is best suited to your growing space, skills and means.

If you have limitations concerning height, or you want to grow the maximum number of plants per square meter, you should use a technique called Sea Of Green (SOG), using strains with little growth and short internodal distances. Ideally, with this growing method you should grow mostly Indica cuttings, but you can also use seeds. If you use seeds, plants are usually moved into flowering indoors when they are between 20-25 cm in height. Naranchup and Black Bomb and are ideal plants for this technique because their growth is homogeneous and they don’t stretch much during flowering.

On the other hand, if height is not a problem for you and you are looking for growing large plants, you should use different techniques, which include supporting the plants with meshes or selective pruning.

If you have any queries concerning the necessary growth period for a particular strain according to your growing tent, leave a comment here and we will be happy to help.

All the best from Philosopher Seeds.