The Basics of Hemp Growing: A Comprehensive Guide for the Beginner

Are you interested in growing hemp, but not sure where and how to start? In this guide, we will learn about the most important basics related to hemp cultivation.

In this guide, we will learn about the most important basics related to hemp cultivation that every grower should know before starting a breeding project. We go through the life cycle of the plant as well as the necessary tools and supplies related to indoor cultivation.


According to the Finnish Penal Code, the cultivation of hemp is a punishable act if the intention is to use it as a drug. Even sowing or planting a plant can become punishable as a drug offense.

Hemp ( Cannabis sativa ) is a versatile plant that is utilized as food and medicine as well as a raw material for many industrial commodities.

Domestic cultivation of hemp varieties used as medicine and intoxicants is really popular today. According to a study conducted by THL in 2011, as many as 40,000 to 60,000 Finns were estimated to have grown cannabis at some point in their lives .

Growing hemp is a project that requires not only patience but also a basic understanding of the plant and gardening. There are a few basic things every breeder should know about hemp.

Sativa, indica and ruderalis – What are the differences between these?

Generally, hemp is considered to be of three different species; Cannabis sativa, Cannabis indica and Cannabis ruderalis .

  • Cannabis Sativa – Sativa varieties occur naturally in tropical sunny areas near the equator. They are characterized by narrow leaves and height compared to other varieties. In nature, they can grow up to 5 meters high. Sativos have a longer growing time compared to other varieties. They usually bloom for about 12-16 weeks.
  • Cannabis Indica – Indica varieties occur in nature in Central and South Asia and the Indian subcontinent. They are lower, bushy and broad-leaved compared to sativos. Indica varieties usually grow in the wild up to 2 meters in height. Indicas bloom faster than they rained (about 8-12 weeks).
  • Cannabis Ruderalis – Ruderalis is a variety that grows wild in the north and under very demanding conditions. They are small in size and only grow to about 30-80 cm in height. Ruderalis varieties usually have a low THC content and are therefore of little pleasure as an intoxicant. However, it is crossed with other varieties due to its autoflower properties.

A very common misconception is that these varieties describe the effects of the plant. Sativa varieties are often said to have more energetic and perky effects, while indica varieties are more relaxing.

In reality, whether the variety is indica or sativa is about the appearance of the plant, not about its effects! There are thousands of crossings that differ in their chemical composition and, consequently, in their effects, and the generalizations of effects mentioned above are completely useless .

It would be much more essential to know the amounts of active compounds such as cannabinoids and terpenes present in hemp .

More information on the effects of hemp can be found in the article below

Sex (male and female)

Hemp is a dicotyledonous flowering herb, a plant in which the mother and peduncle flowers are in different individuals. This therefore means that hemp can grow both male and female plants .

See also  Hemp - What is it and what is it used for?

Of these, the inflorescence of the female plant, i.e. the mother, is the one that is grown for use as an intoxicant or medicine. Male plants, or stamens, are mainly used by seed breeders.

Unless the goal is to produce seeds, male plants should be disposed of as soon as possible.

It is important for the breeder to be able to identify the sex of the plant at the earliest possible stage. When it gets far enough, the fruit plant pollinates the crop, at which point seeds begin to appear in the sow flowers. This negatively affects the quantity and quality of the crop.

If the growing environment is wrong or the treatment is too harsh, the plant may freak, ie start growing both suckler and peduncle flowers. Such an individual is called a hermaphrodite.

This can be due to either poor genes in the variety, too harsh handling, or growth conditions such as irregular light periods.

The best remedy for hermias is to make sure that the conditions and hygiene of the rearing are in order and that the equipment (timers, etc.) works as it should. In addition, the use of high quality seeds or cuttings is important.


Growth stages and plant life cycle

The life cycle of the hemp plant can be divided into three primary stages: germination, growth and flowering .

It is important for the grower to understand these, as the plant’s need for nutrients, water, and light varies at different stages.

Duration3 to 7 days1 week – 2 months2 – 4 months
Light cycle16/812/12
Temperature20-25 ° C22-28 ° C20-26 ° C
Humidity65 – 80%40 – 65%40 – 50%


If the project starts with seeds, the first step is seed germination. Germination is the process by which roots and seedlings begin to grow from seed.

In germination, water is absorbed through the shell inside the seed. When the seed has absorbed sufficient moisture, the outer edge of the seed opens and within a few days the first signs of rooting appear.

The duration of the germination phase varies slightly depending on the seed, but usually the first signs of roots begin to appear within a week at the latest. At this point, the seeds are ready to be transferred to the final medium.

Seed germination is easy and can be done in many different ways. The most common ways are germination between damp kitchen paper or in a glass of water. There are also separate germination media (e.g. Root Riot, Jiffy pellets).

The seeds can also be germinated directly in the soil or in the medium used. The advantage here is that the germinated seeds no longer need to be transferred separately to the final growing medium.

Growth or vegetative stage

During the growth phase, the plant develops strong roots and stems for the flowering phase. In the early stages of vegetative growth, the first leaves and new stems appear on the plant.

During the growth phase, hemp needs light 16-24 hours a day. So the lights can be on around the clock, but some growers already want to give the plants darkness and rest at this point. To adjust the light cycle, a timer is required, which is a necessary acquisition at the latest at the flowering stage.

See also  Basic information about cannabis and its use

The length of the growth phase varies from a few weeks to more than ten weeks, depending on the variety and the breeder’s goals. The length of the vegetative phase very much determines the final size of the plants. Longer growing time means larger plants.

At this stage, it is also possible to influence, for example, the height and shape of the plant. Especially in smaller farms, it is worthwhile to try to spread the plants evenly over as wide an area as possible. The most commonly used techniques are germination, tying and SCROG.

During the vegetative phase, the plants are particularly hungry for nitrogen. Make sure you have a high-nitrogen fertilizer for the growth phase. At this point in the life cycle of the plant, the humidity should be quite high, between about 50-70%.

Flowering stage

During the flowering stage, the plant, as its name implies, begins to produce inflorescence. With normal and feminized seeds, flowering begins when the light cycle is changed to 12/12, i.e., the plants are given 12 hours of darkness and 12 hours of light. Autoflower seeds begin to bloom on their own, without changing the light cycle, in about 2-4 weeks.

After changing the light cycle, after a few days the plants begin to stretch and grow rapidly in height. At this point, the plant may stretch to a length of several cents a day and may double or even triple its size, so make sure you have enough space available.

Humidity should be significantly lower than in the growth phase, about 40-50%. This is very important as excessive moisture during the flowering stage exposes the plants to mold.

The plant clearly shows its sex at the beginning of the flowering phase. If you use regular non-feminized seeds, at this point at the latest you should be careful and get rid of male plants.

Cannabis blooms for about 6-15 weeks, depending on the variety. Indicators usually reach maturity in about eight weeks. Sativat ripens more slowly, about 10-15 weeks.

When a plant is ready to be felled and whether the inflorescences are ripe can be deduced in many different ways. The most reliable way is to observe the trichomes of the plant.

In the plant still raw, the trichomes are translucent and bright. As the inflorescence ripens, they gradually become more turbid.

Many growers rush with the harvest because there is a hard rush to get to enjoy the fruits of their own labor. However, it is worth staying patient and waiting in moderation until the inflorescence is ripe.

The inflorescences swell and condense just in recent weeks, and unnecessary harvesting can really affect the quantity and quality of the harvest you get!

How long does it take to grow hemp?

When grown from seed, the crop is ready in about 3 months at the earliest. On average, hemp indoor cultivation takes about 3-5 months per harvest. The growing time largely depends on the variety used and the length of the growing phase.

If it is important for you to harvest as quickly as possible, the best way to minimize growing time is to choose a variety that matures quickly.

See also  Industrial hemp


The last stage of the breeding project, ie harvesting, is also an important part of the process. A well-executed harvest is essential to obtain the highest possible quality end product. On the other hand, a poorly done harvest can, in the worst case, really ruin your crop.

The stages of harvesting are plant felling, trimming, drying and curetus .

Putting down plants

The first step in harvesting is, of course, felling the finished plants. The plants are cut into smaller pieces so that they are easier to trim or set to dry.

Trimming, i.e. pruning of extra leaves and stems, can be done either immediately after felling while the plant is still wet or alternatively only after drying. This is entirely a matter of taste, and every breeder can do as they see fit.

The trim leaves that grow in inflorescences contain active ingredients and should by no means be wasted. They can be used to make concentrates, such as hashish and oils, or used for baking, for example.


Fresh cannabis contains about 75% water. In order to make the inflorescences combustible, the excess water must first be dried off.

Ideally, drying takes place in a dark, dry and cool well-ventilated area.

  • Darkness – If possible, drying should take place in complete darkness, as UV light from the sun or artificial lights during the drying phase can damage cannabinoids and terpenes in the inflorescences.
  • Ventilation – Ventilation and ventilation of the drying room must be provided to prevent the temperature and humidity from rising too high. However, do not point the fan directly at the plants, as this will cause them to dry unevenly.
  • Humidity – Excessive humidity exposes plants to mold and bacteria, while in too dry plants dry unnecessarily quickly. The good humidity in the drying room is between about 45 and 55%.
  • Temperature – Temperature also affects how quickly inflorescences dry out. The ideal temperature is between about 18 and 20 degrees Celsius.

It is very important that the inflorescences are not dried too quickly, as this will negatively affect the taste and quality of the final product.

Generally, drying takes about 7 to 15 days. The drying process is complete when the shaft snaps when bent. If the stem just bends but does not snap, the inflorescences should be allowed to dry even more.

During the drying phase, especially during the first days, the smell of the inflorescences is really strong, so you should also take care of adequate odor removal.


Once the inflorescences have dried enough, you should still curet them before use. The purpose of this step is to reduce the amount of leafy greens and improve the taste of the dried inflorescence.

In Curetus, the trimmed and dried inflorescences are loosely packed in an airtight glass jar. The jar should be stored in a dark and cool place.

During the first two weeks, it is important to open the lid of the jar a few times a day to allow excess moisture to escape from the container. Later, it is enough to open the lid a couple of times a week.

If you see mold in the inflorescences or the jar becomes a pungent, strong urine-like smell of ammonia, it is a sign that the inflorescences are too moist. In this case, the inflorescences should be set to dry again and the moldy parts should be removed immediately.

Curetus can last from two weeks up to more than two months, depending on the breeder’s preferences.

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