Do you ever pause to consider air humidity in your grow room? This is a topic that novice growers tend to overlook, to their cost. Managing ideal air humidity conditions can be a major factor in growing cannabis seeds into strong, healthy plants. Too much moisture can impair growth and increase risks of bud rot and mould, but low humidity comes with its own risks and problems. That’s why this blog explains all about the best cannabis air humidity conditions, and how to manage them.
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The importance of controlling cannabis air humidity
Basic fact: your cannabis plants need water. Period. How much water they need, however, largely depends on the relative air humidity of the grow environment. High humidity enables plants to absorb water from the air through their leaves, reducing the need to absorb it through their roots. Conversely, plants will drink more using their roots of air humidity is low.
This is a mechanism that growers can use to their advantage. Of course, the water you use to feed your plants directly may contain nutrients that help boost growth. That only makes controlling air humidity levels more important, though, as this in turn affects the uptake of nutrients as a result of root activity.
Air moisture levels can be used to influence other factors too, however, including growth rates, production of THC and other cannabinoids, and presence of mould such as bud rot.
Consequences Of High And Low Humidity
Cannabis humidity levels have a huge impact on your plants. Too high or too low air moisture percentages can cause very real problems. As mentioned, air humidity affects how much water your plants will absorb through their roots. They will drink much more in dry air. Pair this with high temperatures and you can be sure they will drink their fill, which can easily result in excessive nutrient uptake. If your plants absorb more than they need, nute burn may result, causing the leaves to turn yellow or display the characteristic ‘scorched’ edges of nutrient burn.
A major problem related to high cannabis air humidity is mould formation. While high humidity tends to be good for young plants, you should always be wary of mould issues including powdery mildew and bud rot. Ensuring you have proper ventilation in place is a good way to prevent fungi from spoiling your grow.
Improving your control over grow room moisture levels will benefit your plants’ overall development. Cannabis air humidity needs vary as plants go through different stages of their life cycle, however. Young plants prefer high humidity, while more mature specimens tend to need less as they enter the flowering phase. If your cannabis air humidity does not match the phase your plants are in, their growth will suffer and you will end up with sub-par harvest results.
Cannabis Air Humidity For Outdoor Growers
Outdoor growers have very few means at their disposal to control their cannabis air humidity levels. Factors such as sunlight, heat, and shelter form wind and rain are easier to manage than air moisture levels. Even though opting for a greenhouse can considerably improve control, outdoor cannabis humidity levels air far more difficult to influence than grow room or tent moisture percentages.
Absolute Or Relative Humidity?
Air humidity is an indicator of how much moisture the air can contain. It can be expressed in terms of either absolute or relative humidity.
Absolute humidity is the simplest quantification, indicating how much water is present in a given volume of air. The problem is, however, that warm air can hold more water vapour than cold air. This is due to the fact that hot air has more energy to turn water into vapour and keep it in that state. This means that even if absolute humidity stays the same, warm air has lower relative humidity than cold air.
We know this is a bit of a technical detour, but don’t worry: as long as you stick to relative air humidity, you should be good.
Relative humidity (RH) is the go-to expression in most fields of application. It measures the amount of moisture the air contains relative to the maximum amount the air can contain at a given temperature.
The Best Cannabis Air Humidity For Veg And Flowering Stages
Since ideal cannabis air humidity levels differ for each respective stage of a plant’s life cycle, it is essential to adjust them accordingly. We have listed the ideal cannabis air humidity levels for each stage below:
- Clones and seedlings: 70% RH; temperature 24 to 16.5 degrees;
- Vegetative/ growth stage: 60% RH; temperature 20 to 25.5 degrees;
- Early flowering: 50% RH; temperature 18 to 24 degrees;
- Late flowering: 40 to 45% RH; temperature 18 to 24 degrees.
As you can see, the table indicates both an ideal RH value and a temperature range. This underscores the relationship between perfect cannabis air humidity conditions and temperature as we indicated above. Different plants in different life stages will thrive within differing relative air humidity ranges, which correspond to ideal temperature ranges. That means that controlling your perfect cannabis air humidity automatically includes keeping ambient temperature in check.
How To Provide Ideal Humidity
Anyone growing cannabis in a grow tent is in a good position to provide ideal humidity values. Installing a hygrometer will give you accurate insight into current RH values, usually accompanied by temperature measurements for convenience.
The easiest way to keep cannabis air humidity values constant is using a humidifier and dehumidifier in your tent or grow room. Of course, such equipment is an investment, but your return on this investment is accurate moisture control at the mere push of a button.
If you can’t afford humidifier equipment, you can opt to regulate your cannabis air humidity manually. It will be considerably less accurate, but it’s still a good alternative for novice growers. We’ll explain to manage either method below.
Dehumidifying The Air
An air dehumidifier will draw moisture from the atmosphere automatically. Some devices can be connected to a drainage system, while others have their own reservoir that you’ll have to empty when full. Another means of lowering RH is using ventilation to control moisture levels.
Place a swivel fan, or oscillating fan, and ensure that your tent or room supports adequate exhaust capacity. Aim your fan so that the airflow brushes along the canopy, leaving the leaves swaying gently in the breeze. The circulating air will carry off any excess moisture, thus improving uptake of nutrient and water supplies.
An important cause of excessive cannabis air humidity levels is overwatering. Many rookie growers tend to give too much water to their plants, simply as a token of their dedication and budding love of growing. You can easily end up saturating your soil substrate, causing excess moisture to evaporate and increase existing moisture levels. Always make sure not to overwater your plants!
A final option for regulating cannabis air humidity without dehumidifiers is to prune away a few excess leaves from the foliage canopy. A dense canopy can easily raise your cannabis air humidity above ideal values, mostly by disrupting airflow and blocking ventilation efforts.
Increasing cannabis Air Humidity
If you need to increase humidity rather than lower it, your easiest option is buying an air humidifier to add moisture to the grow room or tent. Evaporation humidifiers come with the added benefit of lowering temperatures while they add moisture. Humidifiers with large water reservoirs are a smart choice that will prevent you from having to replenish your water supply several times a day.
If you are not in a position to buy special equipment to regulate your cannabis air humidity, you could try placing a bucket of water in your grow room instead. This will help to gradually increase your cannabis air humidity. Another viable option is using a nozzle sprayer. Simplistic as this technique may sound, it is still an effective if labour-intensive way to increase your RH values by hand
Whichever technique you prefer, always make sure to keep your humidifier equipment clean and use fresh water, or you’ll risk turning perfect cannabis air humidity into a giant mould and bacteria hazard.
As you can see, it’s not that hard to improve your control over optimal cannabis air humidity in your grow room, whether you have special equipment or not. Making sure your plants keep enjoying perfect relative humidity will surely improve your prospects of enjoying strong, healthy plants with beautiful buds.
Optimal Cannabis Air Humidity For Drying And Curing
After harvesting, the time has come to dry and cure your buds. Obviously, these processes depend heavily on RH values in your drying room and mason jars. Too much moisture will prevent any remaining water to evaporate from the flower buds. Too dry conditions may speed up the drying or curing process beyond acceptable limits, resulting in loss of flavour and potency.
When starting to dry cannabis air humidity levels should be about 50%, at around 20-degree temperatures. After three or four days, raise RH to 60% while lowering temperatures to about 18 degrees. Make sure to keep your grow room airflow moving as you proceed.
After drying comes the curing process that will elevate your weed’s flavour, fragrance, and potency to perfection. The best curing environment supports cannabis air humidity levels ranging from 60 to 65% at temperatures around 20 degrees. As our special drying and curing blog explains, it is essential to regularly open your mason jars to allow moisture to escape while drawing fresh air back in.
You’re Good To Grow!
Now that you know how to control your cannabis air humidity throughout the entire grow, you’re all set to start growing premium cannabis seeds. Just pick the seeds that match your personal taste and grow goals and order them directly from our online store: we usually ship them out on the same day.
Pick The Best Seeds
If you’re keen to find out more about the best conditions for growing cannabis seeds, or looking to improve your game to make the most out of every seed you germinate, check our Grow Blogs and watch your knowledge flourish as bountifully as the plants you raise!
