These are the most common mistakes when growing cannabis indoors

Indoor cannabis cultivation has become increasingly popular among cannabis lovers.

The possibility of growing marijuana at any time of the year has led to an exponential growth of home growers. However, it is common to make mistakes that negatively affect the yield and quality of crops.

1. Choosing the wrong lighting equipment

One of the most common mistakes is to use inappropriate lights for marijuana growing. Specific lighting kits for cannabis cultivation are essential, since they provide the power and color spectrum necessary for a good development of the plants.

Using bulbs or LEDs not designed for marijuana cultivation causes low performance and unnecessary energy waste.

2. Too many plants in the crop

A common mistake is to overcrowd the growing space with too many plants.

Although it may seem logical that more plants mean more buds, in reality, plants need their space to grow and develop properly.

If plants are too close together, they will compete for light and stretch upwards, resulting in low yields. The number of plants will depend on the available growing area, being advisable to place between 9 and 16 pots per square meter.

3. Using a substrate of low quality

Using a substrate of low quality can have negative consequences on the growth and development of the roots.

Commercial substrates for marijuana are specially formulated to provide the optimal conditions of humidity and aeration needed. These substrates are usually composed of a mixture of peat, coconut fiber, perlite and organic matter.

When choosing a substrate, it is important to consider its water-holding capacity and air-to-water ratio.

4. Light pollution

Light pollution negatively affects indoor cannabis cultivation. It is important to recreate optimal outdoor conditions, preventing plants from receiving light when it is not appropriate. Keep in mind that inadequate light generates stress in plants and even causes problems such as revegetation or hermaphroditism.

To avoid this, it is advisable to check the growing space in complete darkness to detect any unwanted points of light and cover them if necessary.

5. Lack of temperature and humidity control

Maintaining proper temperature and humidity is essential for successful cultivation. It is advisable to use thermometers and thermo-hygrometers to monitor these parameters constantly.

Inadequate ventilation can hinder the exchange of carbon dioxide and oxygen, directly affecting the plant’s ability to photosynthesize and grow healthily. In addition, a lack of temperature and humidity control can promote the growth of fungi and other pathogens harmful to the crop.

6. Excessive watering

Overwatering is one of the most common mistakes in cannabis cultivation, both indoors and outdoors. Often, for fear that the plants will dry out, we tend to overwater them.

This practice generates problems, as the excess water displaces oxygen from the substrate, weakening the roots and making the plant sick. It is crucial to allow the substrate to dry out between waterings and water only when necessary.

A good way to know when to water is to lift the pot and check its weight.

7. Poor indoor ventilation

Insufficient ventilation has serious negative consequences for indoor cannabis cultivation. The lack of air exchange hinders the influx of carbon dioxide and the removal of oxygen, which directly affects the plants’ ability to photosynthesize.

In addition, poor ventilation creates an environment conducive to the development of fungi and other harmful pathogens. It is essential to have an adequate ventilation system that includes exhaust fans and ventilators to ensure a constant flow of fresh air.

8. Do not use carbon filters

The smell of cannabis indoors can be very intense and persistent. Using carbon filters is essential to avoid problems and maintain discretion in cultivation.

Many novice growers underestimate the importance of odor filters, but once flowering begins, they realize the need for them. Carbon filters help eliminate strong odors and avoid unnecessary problems.

9. Plants that are too large

A common mistake is allowing plants to grow too large in the growth stage. While it may seem tempting to let plants grow larger before moving into flowering, this is not always beneficial. Plants that are too large can have problems with uneven development, as the buds at the bottom tend to receive less light and energy.

Concentrating the tips of the plant at an optimal height ensures higher production and balanced bud development.

10. Not keeping an eye on water temperature

In cold weather, it is common to use cold water for watering plants. However, cold water often negatively affects the roots.

Be sure to maintain an appropriate water temperature of 18 to 22 °C (64 to 72 °F). A solution to avoid irrigation with cold water is to leave the prepared water in the growing space to warm up before use.


There is no doubt that these are the most common mistakes when growing cannabis indoors that you should avoid at all costs.

Remember that knowledge and experience are fundamental to obtain good results in self-cultivation of marijuana. Good luck with your crops!