One of the most critical factors in a successful cannabis cultivation facility is controlling air humidity. It can have a dramatic impact on crop quality and success.
Cannabis plants have a constant need to intake water, and the amount of water they consume changes with air humidity. Keeping humidity levels right helps ensure that your plants drink only the right amount of water and nutrients.
Vegetative Stage
Air humidity is crucial for the proper growth of cannabis plants. In addition to helping the plant regulate its internal temperature, a healthy level of humidity will ensure that the stomata close properly, limiting water loss from the growing medium and reducing wilting and stress.
A high percentage of a marijuana plant’s energy is consumed by maintaining the correct humidity. In the vegetative stage, a higher relative humidity of 80-90% is recommended to promote optimal growth and development.
Young seedlings are particularly vulnerable to low humidity levels. This is because they have not yet developed a radicular system, which means that they are dependent on the availability of water to keep their leaves moist.
This is why many growers will use a humidity dome to provide a favourable level of humidity for young clones. This will dramatically increase the chances that the clones will root successfully and that they will develop a strong radicular system in the future.
Another advantage of using a humidity dome is that it will reduce the risk of fires caused by hot HID bulbs. This is especially important for greenhouses where the risk of fires is a serious issue.
During the vegetative stage, the cannabis plant uses more energy than during any other part of its life cycle. In this phase, the plant also absorbs and retains a lot of carbon dioxide from the atmosphere. This helps it to grow more rapidly and produce more trichomes.
Although the vegetative stage is the most productive phase of the cannabis plant’s life cycle, it is also the most environmentally damaging. Cultivators who are concerned about the environmental impact of cannabis cultivation should ensure that they do not exceed their nutrient limitations during this period.
Aside from the obvious negative effects of excess nitrogen on air quality, nitrogen fertilization also contributes to soil acidification and eutrophication. These issues are relevant to both cannabis and other crops grown in water-sensitive zones.
Additionally, excessive amounts of nitrogen contribute to a decline in the overall carbon footprint of the cannabis plant as well. This is because nitrogen deteriorates the soil’s quality, and it takes time for the soil to recover its lost nutrients.
In addition, the use of nitrogen-based fertilizers can cause groundwater depletion. This can threaten connected watersheds, and is a problem that grows in importance with each passing year.
The most recent study suggests that a number of farms in northern California are pumping significant amounts of groundwater for their cannabis production. This practice can pose a threat to the local and regional water supply, as groundwater reserves recover more slowly from overuse than surface sources.
The vegetative stage of cannabis cultivation is an extremely important phase for both the plant and the environment. It is a vital stage that needs to be monitored carefully for both the health of the plant and its contribution to regional and global air quality.
Flowering Stage
Air humidity is one of the most critical factors in the successful growth of cannabis. Without proper control, humidity levels can be erratic and cause strains to wilt or develop mold and mildew.
The optimum air humidity for the cannabis plant depends on the stage of development, but there are several ranges that should be maintained. Humidity is especially important during the vegetative stage, because it allows marijuana plants to properly absorb water and nutrients.
For the young seedling and clone stages, humidity should hover around 70-70% to ensure healthy root formation. It is crucial to maintain this level when planting seeds or clones to avoid damage from the harsh environment and nutrient deficiencies.
Once the plant reaches the flowering stage, growers should lower their relative humidity to around 40-55%, as increased moisture during this stage can increase the risk of mold, powdery mildew and Botrytis. This reduces the likelihood of developing disease while allowing cannabis buds to draw out more resin, helping the buds produce the highest quality of THC and cannabinoid content.
As the cannabis flower matures, the stomata will begin to close to prevent water loss. The stomata also play a key role in regulating transpiration, as they intake carbon dioxide and expel water vapor.
It is advisable to use an in-duct humidifier during this stage, as it can help improve air circulation and prevent mold from growing on the leaves of the plants. The best humidifiers will also keep the humidity at the optimal levels, ensuring that your cannabis plant gets the correct amount of water and nutrients it needs to achieve the best possible outcome.
The most effective cannabis growers will use a smart humidity system that can adjust the RH in the room, depending on the stage of the plant. It will also be able to detect when the humidity level is too high or too low, which can help prevent these conditions from occurring.
Humidity is also essential during the curing process, as it helps preserve terpenes and slow the drying process. Too much humidity in this stage can make the buds moldy, a major issue that can destroy your reputation as a grower and leave you with unsatisfactory product for sale.
While humidity is vital in all stages of the plant’s life, it is especially critical for successful cannabis cultivation. The cannabis plant has a constantly fluctuating need for moisture, and this requires constant monitoring and adjustment to ensure its optimal needs are met throughout the entire cycle of growth.
If you’re new to the world of growing cannabis, it’s easy to lose track of these details. That’s why we developed our first-ever “Smart Humidity Special Report,” which is packed with data from proprietary research, insights from cultivators and experts on how to apply smart strategies to ensure your cannabis production is the healthiest it can be.
Harvesting
Cannabis plants require different levels of humidity throughout their life cycle. This is largely due to their natural requirement for water intake to develop a healthy root system, and it’s a factor that’s critical to achieving a quality harvest.
The best growers monitor their relative humidity (RH) using a thermo-hygrometer. This enables them to keep a close eye on their environment and ensure that all the necessary conditions are met across the life cycle of their plants.
Humidity is a measure of how much water is being held in the air, and is generally measured in grams per cubic metre. Warmer air can hold onto more water than cool air, so it’s important to maintain a consistent moisture level in a grow room or tent.
For the optimal cannabis growing experience, you should aim to keep your RH between 60% and 75% at all stages of plant growth. If the humidity rises too high, this can lead to issues with mould or bud rot, both of which are undesirable for producing fat, dense main colas and resinous buds that have a pronounced cannabis flavour.
Mold isn’t the only threat to a quality cannabis harvest, as too much dry air can also contribute to nutrient burn and leaf wilting. Both of these problems can slow the growth of your marijuana plants and ultimately result in a poorer product for you to sell at a dispensary or for personal use.
Nutrient burn is caused when a cannabis plant takes in too many nutrients at once. This can cause the leaves to turn yellow and the tips to look burnt.
The buds that result from these conditions are usually ruined, making the product unusable for both you and the user. You can avoid these situations by monitoring the humidity in your grow room or tent.
A good grower will have a good understanding of their local climate and will use a thermo-hygrometer to ensure that the right conditions are maintained in their grow rooms or greenhouses. They may also invest in a dedicated de-humidification unit, such as a Dantherm, to reduce their RH levels to safe levels and minimise the risk of mold and fungus.
As with temperature, the ideal level of humidity is dependent on the age of your cannabis plants. Younger plants, such as seedlings or clones, need higher levels of humidity to allow for water intake and root development.
