Growing cannabis indoors
Growing cannabis indoors is easy. You can buy everything you need online, or from your local garden centre / grow shop. Don’t worry if you have never grown cannabis indoors before, it’s not complicated and most people can master the basic skills quickly. Read on to learn more about: Choosing the best cannabis genetics


  • Choosing the best cannabis seeds

  • Germinating cannabis seeds

  • Grow lights for indoor cannabis growing

  • Nutrients used for cannabis growing

  • Tips  for growing cannabis indoors

Growing indoors


Choosing the best cannabis seeds

Choosing a cannabis variety is of major importance. Yields and quality of plants grown under artificial lights mostly depend on:

1. Seed variety,
2. Whether the plants are grown from seeds or clones
3. After how many days of growing the plants are put into flowering
4. Optimization of the climatic conditions of the grow-room.

Apart from "true breeding" varieties, our seed collection consists of different F-1 hybrids. Crossing two "true breeding" strains (hybridizing) gives F-1 hybrids that possess the so-called "Hybrid Vigor". This means that the F-1 generation is a lot more potent than either parent. F-1 generations also consist of uniform plants.


Feminized seeds and autoflower seeds


Most people grow cannabis indoors with feminized seeds or autoflower seeds.

Feminized seeds grow vegetively for the first few weeks under 18 or 24 hours of daily light. They only start to bloom when daily light is reduced to 12 hours, and take  around 8-9 weeks to bloom.
Autoflower seeds grow from seed to harvest in around 75 days under 20 hours of daily light. Many people find them the easiest, fastest and most convenient way to grow cannabis indoors.
In general, cannabis seeds with indica genetics tend to produce shorter plants, and sativa varieties tend to be slightly taller and can stretch more during bloom.
CBD rich cannabis seeds Produce cannabis that contains 4% CBD (or more) in the dry buds. These are popular with medical growers, the high may not be quite as intense as a typical THC rich variety.

Cannabis indoor growing


How to germinate cannabis seeds


Germinating cannabis seeds can be done in various ways and the internet is full of cannabis grow forums that document various methods. The Dutch Passion cannabis seed germination guide lists several of the most popular ways to germinate seeds. One simple method is to simply place seeds about 1cm below the surface of firmly pressed damp soil. A film of transparent kitchen film over the surface helps keep conditions moist and after a few days of temperatures around 20-25°C the seeds should germinate. Growing from cuttings of mother plants is an alternative to growing from seeds.

In the first stages of life the seedlings are happy to start with lower light intensities often a metre below an HPS light (closer for fluorescent lights). The artificial lights are normally on for 18-24 hours per day. During this time the seedlings are in a state of vegetative growth, they will continue to grow roots, leaves and branches but no bud.

Putting your plant into flower mode, and harvesting the end result.

By reducing daily light to 12 hours the feminized cannabis plant transitions into the ‘flowering’ phase. This stage normally requires 8-10 weeks (but more for certain strains) and it is during this time that the female flowers form. During this stage the plants grow heavy blooms and will tolerate more nutrients and very bright light. Some growers introduce supplemental lighting to ensure the very best yields. At the end of this process the plant is cut down and the buds (un-pollinated female flowers) are dried. Some growers harvest the plants when they see the trichomes starting to transition from clear to cloudy (this requires a magnifying glass). This often coincides with the bud producing lots of red/orange pistil hairs. Some smokers prefer bud harvested early, others prefer late-harvested bud. When you grow your own cannabis indoors it is you that decides exactly how you like it!

In general, longer periods of vegetative growth will grow larger plants and support greater yields during subsequent flowering. Typically 4-5 weeks of vegetative growth are used and during subsequent flowering the plants may increase to 2 or 3 times their original height. Some growers use the ‘sea of green’ (SOG) method, this uses just a few days of vegetative growth before switching to ‘flowering’ conditions. This technique produces small plants of low/medium yield, but allows for fast production.

Male plants are nearly always destroyed by the indoor grower as they don’t yield any buds, and given the chance they will pollinate the female plants reducing them to seed.


Grow lights for indoor cannabis growing


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Cannabis loves light and the successful indoor grower tries to deliver as much light as possible. Consider 250 watts/m² only as an absolute minimum starting point and realistically aim for 2-3 times that level. More light will mean bigger, denser buds and superior yields. As well as delivering high light levels the successful indoor grower keeps the plants close to the light to maximise the light intensity reaching the leaves and buds. Often the personal medical or recreational indoor cannabis grower will have a growing tent of about 1.2 m² with a 400W or 600W high pressure sodium (HPS) lamp.

The indoor cannabis grower has to be careful that the plant doesn’t grow too near to the hot light and damage itself. If the light feels cool to the back of the hand it will be cool for the plant also. For a 400W lamp, growers may not want to allow plants to grow within 40-50cm of the bulb. Cannabis plants can be bent over and tied if they get too tall, some indoor growers deliberately train their plants this way to get as much of the plant as possible close (but not too close) to the high intensity light.

If you are buying an LED grow light we recommend the website of Led by Passion, our sister company. All the grow lights have been designed for growing cannabis, the grow lights have all been tested and approved before being added to the collection. The worlds best LED grow light brands are all represented.

Certain strains respond well to having the growing tip of the plant pinched out (known as ‘topping’, ‘FIM’ or pinching) after the 4th or 5th leaf pair. The resulting plants are often smaller and bushy without the dominant main growth stem (or ‘cola’) and are preferred for some smaller growrooms.


Nutrients used for cannabis growing


Growing cannabis indoors will require use and understanding of plant feeds. This is not complicated, all the plant food does is deliver essential nutrients to the roots, it doesn’t matter whether the roots are growing in clay pebbles, rock-wool, coir or a hydroponic system. Even soil-grown plants will need additional nutrients when the soil has been depleted. Read the instructions on the nutrient labels and avoid the beginners temptation to exceed recommended levels. The experienced gardener can ‘read’ his plants and will learn when to water and feed plants. If you see the tips of the leaves go brown and crispy it could be due to over-feeding. If this happens reduce feed concentration immediately and consider flushing with water.

Indoor growing allows the plants to develop under closely supervised grow conditions without the normal array of outdoor pests and bad weather. Once the grower has the right system in place it is a predictable way of growing great quality cannabis, a lot better than weed sold by street dealers. The main challenge for many indoor cannabis growers is dealing with the characteristic cannabis smell so that no-one notices it. Ensure your carbon filter is working well, and replace it if it isn’t.

Recreational and medical cannabis popularity now extends far outside the earths warm/tropical climates. So for many people, growing cannabis indoors is the only option. Growing cannabis indoors has never been as popular as it is today, nor has it been as easy to produce superb quality weed. Professional seed suppliers, equipment providers, advice and information are all available on the internet.


Tips for growing cannabis indoors


Growing cannabis indoors has seen a dramatic rise in popularity in recent years. When done properly it produces excellent quality cannabis which is usually much better than that sold on the streets.
Growing cannabis indoors relies on the use of powerful artificial lights to replicate the effect of the sun. The ‘average’ home grower has a 1.2 x 1.2m tent or similar and usually has a light between 100-1000W. The 400W and 600W HPS grow lights have been favourites with indoor cannabis growers for many years. More modern LED grow lights produce better results, with higher THC levels but at a higher cost. A carbon filter and extraction fan are essential items for any indoor cannabis grower. Your local grow shop, or an online supplier will have all the necessary equipment and usually can provide good advice. They will also supply nutrients.

Growing cannabis indoors at home

Some indoor growers train the plants underneath a metal wire mesh screen allowing only the buds to grow vertically while the stem and growing part of the plant are trained horizontally. This SCROG (screen of green) technique allows the indoor grower to keep as much of the bud growth as possible equidistant to the lamp, maximising the efficiency and yield.

Specialist suppliers offer ‘air cooled’ lights for the indoor grower that enclose the light in a glass casing. A fan forces air over the light and outside the grow-room via tubing, keeping the grow room cool and allowing the plants to grow taller without burning. Grow rooms are typically kept around 25°C for optimum results. Higher temperatures can cause the plants to wilt and cooler temperatures may slow down growth. The plants will need a gentle breeze from a fan, and a steady supply of fresh air which can be from your house or from outside. Stale air from the growroom is normally continually extracted outdoors by a fan and the pungent cannabis aroma is removed with a carbon filter.

Those indoor growers that do get caught are often betrayed by the smell of their growroom, so some people also invest in ozone generators to further remove odours from the exhausted grow room air.

Choose feminized seeds for indoor growing

Feminised seeds are popular with the indoor growers as they virtually eliminate the possibility of male plants. For many indoor growers feminised seeds from a quality supplier are regarded as the only way to grow.

The indoor grow-room allows plants to be grown in soil or any number of other grow mediums. When growing in soil the cannabis plant benefits from 25% perlite or coco fibre being included. This allows better aeration of the soil and more oxygen for the cannabis roots. One common mistake by inexperienced growers is the tendency to overwater/over-feed soil-grown plants. Get to know the weight of your plant pots and water only when the plants need it. Over watering soil-grown plants will reduce yield/quality and slow down plant development.

Get cannabis seeds online

Buy autoflower seeds here

Successful indoor cannabis growing begins with the best cannabis seeds – get them from a supplier you can trust. The price difference between the best seeds and budget seeds is small in comparison to the value of the cannabis that is produced. Dutch Passion have been in business since the 1980’s supplying the best cannabis seeds with the highest THC levels and the most pleasurable highs. You can buy feminized seeds online from Dutch Passion, or you can buy autoflower seeds online. Both cannabis seed types are easy to grow and will deliver heavy yields. Dutch Passion also sell regular cannabis seeds. Buy Dutch Passion cannabis seeds online and you get decades of expertise and some of the best cannabis genetics available.

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Dutch Passion advise their customers to reassure themselves of local applicable laws and regulations before germination. Dutch Passion cannot be held responsible for the actions of those who act against laws and regulations that apply in their locality. Cannabis seeds should be kept as collectible souvenirs by anyone in an area where cultivation of cannabis is not legal.