Cannabis growers often wonder how different temperature ranges will affect their plant’s growth. They may also ask what will happen to their plants if they are grown in temperatures that are too cold.
During the vegetative stage, optimal temperatures for photosynthesis range between 20 and 30 degrees Celsius. This is ideal for young plants that are growing quickly in the heat.
Optimal Temperature Ranges
Keeping your cannabis grow room temperature at the right range is vital for optimal growth. Temperatures that are too warm or too cold cause stress for the plant, which may hinder growth.
In general, marijuana plants prefer a warm temperature during their vegetative phase when lights are on and a cooler temperature during their flowering stage. This helps the plant convert nutrients into energy for growth, which is critical for high yields.
The ideal temperature range during the vegetative phase is 76 to 78 degrees Fahrenheit when lights are on and no more than 10-15 degrees cooler at night with a relative humidity of 45 to 55 percent. This helps the plant absorb the proper amount of water to produce strong, healthy leaves and branches that support a robust root system.
Young growing cannabis plants also require a higher level of humidity than more mature plants in the same phase. They are still developing their root system, so they need high levels of humidity to absorb water through their leaves.
As cannabis plants progress through their life cycles, their ideal humidity ranges fluctuate to meet the different stages of development. The seeds and cuttings (clones) stage requires humidity levels between 65 to 70 percent, while the late flowering period requires lower levels of 40 to 50 percent.
To control temperatures, consider using heat extractors, fans, and cooled lighting systems. In addition, CFL bulbs and LEDs can be used to help reduce heat output in your grow space.
When choosing a light source, choose LEDs that emit less heat and include the full spectrum of visible light. These types of lights are affordable and don’t use much energy, which means you can install them closer to your plants for a more productive outcome.
A hygrometer can help you keep track of your grow room’s humidity levels to prevent mold and mildew formation during the vegetative and flowering stages of your cannabis grow. It is also a good idea to lower your relative humidity levels during the final weeks before harvest, as this will prevent powdery mold, mildew, and bud rot from infecting your buds.
Optimal Humidity Ranges
Humidity is the amount of water vapor in the air, and it is an important factor to consider when growing cannabis. This is because humidity affects the amount of water that a plant takes up from the soil or from the air around it.
It also plays a role in controlling water loss through transpiration, nutrient uptake, and photosynthesis rates. To achieve optimal conditions for a cannabis grow room, it is important to keep humidity levels between 40 and 60 percent.
The best way to measure the moisture level in your grow room is to use a hygrometer. These small devices can be easily placed over your plants and will provide you with an accurate reading. They are cheap and easy to use, and you can find some great models at this link.
While seedlings and clones prefer higher humidity, mature plants need lower levels to promote healthy growth. This is because they have much smaller roots and can absorb more moisture from the surrounding air.
As a result, it is important to maintain the correct humidity levels throughout the entire grow cycle. This is a good way to ensure that you are growing cannabis in the right conditions, and it will help you maximize your harvest potential.
There are many different factors that influence the ideal humidity ranges for cannabis, including region, genetics, and growth stages. But a few general guidelines can help you get started.
1. Younger Cannabis Plants Need High Humidity:
Seedlings and clones are little cut-off pieces of parent plants that need to develop root systems. They need high humidity to allow them to absorb moisture through their leaves.
2. Temperature for Younger Cannabis:
Optimal temperatures for young cannabis plants are between 75 and 80 degrees Fahrenheit. This is because the temperature is best for photosynthesis and for enzymes to work efficiently.
3. Vegetative Stage:
Vegetative stage is the stage of growth when a cannabis plant begins to take on its leaf shape and start producing flowering buds. As a result, it is essential to keep the humidity within a comfortable range to support healthy growth and a bountiful harvest.
Optimal Light Ranges
Cannabis plants have a unique light spectrum that they need to thrive and grow. This is why it’s important to use the right lighting system for your grow space. The correct grow light will ensure optimal photosynthesis and optimum harvest yields.
During the vegetative phase, young plants need a blue light spectrum to promote healthy stems and established roots. It also drives peak chlorophyll pigment absorption which is vital for plant photosynthesis.
When it comes to flowering, cannabis plants need a red-light spectrum to promote growth and prolong the flowering period. This helps to produce large, dense buds for pollination.
This color range is also effective at reducing environmental stress, fungus and pests. It can also increase THC potency by boosting the absorption of UV-B light.
While red and blue lights are the most common and widely used in greenhouses, there are other types of light that can have a positive impact on cannabis growth. These include ultraviolet (UV) light, which is comprised of three bands: UV-A (315-400 nm), UV-B (280-315 nm), and UV-C (100-280 nm).
Most indoor growers are best served by using fluorescent or LED grow lights with a color temperature between 4,500 and 6,500 Kelvin for vegging and 2,800 to 3,500 Kelvin for flowering. You can also find grow lights that combine the best qualities of both of these light spectrums, ensuring optimal growth for both phases.
In addition, many growers are finding that the green color range in LED lights can still be useful. While it’s thought that green wavelengths don’t have as much of an impact on photosynthesis, research has shown that they can still be beneficial to the health and growth of your plants.
It’s also important to keep in mind that there are different stages of the cannabis life cycle, and each stage requires different wavelengths of light. During the germination and veg phase, young plants require light with a high blue-light spectrum that can help to stimulate growth and produce healthy seedlings.
As your plants enter the flowering phase, it’s important to make sure you have a light with a red-light spectrum that will promote flowering and increased THC potency. This is particularly true of outdoor cannabis growers who are growing their plants during late summer and fall when the sun’s daylight hours begin to decline.
There are a number of different factors that can determine the optimal temperatures for your cannabis plants. Temperatures can affect internodal growth, water absorption and respiration, PH levels, and the nutrient balance in the growing medium.
Optimal temperature ranges are necessary for healthy growth of any plant, but they are especially important for growing cannabis. During vegetative and flowering stages, the ideal temperatures help ensure that your plants thrive and produce quality buds.
Young cuttings, or clones, are more sensitive to the effects of temperature than other cannabis cultivation phases because their initial focus is on root establishment and they do not have enough internal resources (roots and leaves) to harness higher-stress environments. During these early growth stages, you should keep temperatures low, around 65 degrees Fahrenheit.
You can also use a heat extractor to lower your grow room temperature by sucking warm air out of the room. This will lower the overall room temperature as well as CO2 and other greenhouse gas emissions, creating an ideal environment for cannabis to grow.
Another way to maintain optimal temperatures is to install a two-stage thermostat so that you can set and control the temperature of your grow room at night and day. These two-stage thermostats are a little more expensive than single-stage ones, but they allow you to set and maintain temperatures at the optimal levels for your plants.
In the end, it is vital to make sure that you maintain a proper balance of humidity and temperature in your grow area throughout the entire lifespan of your plants. This is important for ensuring that your plants have the best chance of reaching their full potential and producing high-quality, nutrient-dense buds.
As we mentioned earlier, the ideal temperature range for growing is 76 to 78 degrees Fahrenheit during the day and 65 to 68 during the night. This helps to encourage healthy and robust leaf and stem development while minimizing stress.