Best Temp And Humidity For Germinating Weed Seeds

Cannabis is a high-value plant that has come to be primarily cultivated indoors due to its high sensitivity. Each stage of cannabis growth requires a specific kind of tune-up to achieve optimum growth and obtain high-quality yields. Humidity not only plays a roll in the growth of this incredible plant, but also in the Temperatures and Medical Cannabis Growing: From Seedling to Harvest The marijuana industry created an estimated $34 billion economic impact in 2018. Legal sales of marijuana are expected to In order to produce marijuana buds, the cannabis plant needs to go through 4 growth stages like the germination stage, the seedling stage, the vegetative

What Is The Best Humidity For Growing Cannabis Plants?

Cannabis is a high-value plant that has come to be primarily cultivated indoors due to its high sensitivity. Each stage of cannabis growth requires a specific kind of tune-up to achieve optimum growth and obtain high-quality yields. Humidity not only plays a roll in the growth of this incredible plant, but also in the proper curing of cannabis, and in proper storage containers and conditions while in storage.

While many cannabis growers identify sensitivity to the condition of the soil and the nutrients available for the plant, it’s environmental conditions that really matter. One of the environmental factors that affect the growth of cannabis is humidity.

Humidity can be defined as the amount of water vapor in the air. Generally, there are three types of humidity:

  • Specific humidity – The specific humidity of an area is the ratio of the amount of water vapor to dry air.
  • Absolute humidity – This is the actual amount of water vapor present in a given area.
  • Relative humidity – This is the ratio of the actual amount of water vapor present in an area compared to the speculated maximum amount of water vapor that the area can hold.

In cannabis growth, as with any other plant, the relative humidity is used. It is also worth noting that humidity and temperature are interrelated. The amount of water vapor that air in an area can hold increases with increasing temperature.

What Factors Affect Relative Humidity Control For Cannabis?

There are three basic factors that weigh heavily in determining the correct relative humidity when growing cannabis plants. They are region, genetics, and stages of growth. Although there are lessor and differing situations, these three have the greatest impact.

Region

Cold regions have less moist air due to the temperature relation stated above. Growing cannabis in these areas means that the relative humidity must be increased to an optimum level. On the other hand, hot or tropical regions require less control of humidity as most cannabis plants are highly favored by relatively higher humidity.

Genetics

A good number of cannabis varieties have been developed over the years. Some cannabis species are adapted to warmer and more humid areas while others are adapted to cold and less humid areas.

Growing Stages

From germination to late flowering, the cannabis plants call for changes in the humidity levels. Since each stage comes with distinct metabolic reactions, the relative humidity needs also vary.

Why Is Humidity Important For Cannabis Plants?

To understand how humidity affects the growth of cannabis, let’s first understand the plant’s respiration process.

The sugars produced in the photosynthesis process must be converted to energy used to support plants’ growth. To convert the sugars, mainly glucose to energy and oxygen, later released to the environment, the cannabis plant must acquire carbon dioxide from the environment.

The carbon dioxide enters the plant via the stomata; tiny pores on the leaves. When this process occurs, some water from the plant’s water reservoir is lost to the environment. Relative humidity kicks in here as it dictates how much water the cannabis plant will lose to the environment.

Two scenarios can occur:

When the air is moist (high relative humidity)

The water concentration gradient is significantly reduced due to the higher amount of water vapor present in the air. This means that the cannabis plant will lose less water and hence remain in its best shape.

When the air is dry (low relative humidity)

The high water gradient created between the plant and the surrounding air causes high water loss. The marijuana plant will try to prevent this by closing the stomata, a process that compromises the vital respiration process.

In summary, relative humidity is vital to cannabis plants as it regulates the respiration process and its subsidiary activities such as water loss. For a cannabis plant to benefit fully from relative humidity, it must be maintained at an optimum level. It will also help if the humidity is also kept constant for an extended period.

Should Humidity Be Low Or High For Cannabis Plants?

Cannabis plants are grown in a relative humidity range of 70-40%. This is neither too high nor too low humidity. As discussed above, both extremes of relative humidity are potential causes of cannabis plant stagnation. It is also good to understand that high humidity may support the growth of mold that may affect the growth of your marijuana plants.

What Humidity Should I Have In My Grow Tent?

When you cultivate cannabis in a grow tent, conditions such as humidity and temperatures must be appropriately controlled. While by now we know that different growing stages of the cannabis plant require different levels of humidity, it would help if you kept the humidity in your grow tent relatively high for cannabis seedlings. Several factors affect the amount of humidity in your cannabis grow tent. These include:

Lighting

If the lights of your grow tent are always on, the temperature of the contained air is raised and hence the relative humidity. Poorly lit grow rooms have cold and dry air (low humidity).

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Ventilation

If your grow tent is adequately ventilated, the relative humidity is reduced due to increased air circulation. Ventilation is required for mature cannabis plants that require low relative humidity.

Frequency of Watering

Watering cannabis plants in a grow tent increases the plant’s water intake through the roots. High uptake of water by the plant increases the water loss rate through the leaves, making the room more humid. The induced moist environment, in turn, regulates the respiration process keeping the marijuana plant healthy. Again, watering should be optimized to maintain the grow tent in the recommended level of humidity.

What Humidity Is Good For Cannabis Flowering?

The recommended relative humidity for a flowering cannabis plant is 40-50%. The moisture is reduced to this level mainly to prevent the growth of mold that is very vicious at this stage.

Did you know that mold infestation on one cannabis flower can ruin your entire harvest? Lowering the humidity in this stage is, therefore very crucial and should not be overlooked. The humidity can also be reduced below 40% when the cannabis is close to harvest. This, however, depends on how your cannabis plants respond to changes in humidity.

In conclusion, it can be said that humidity is an essential condition in the growth of cannabis plants. Always start with a high relative humidity of about 70% for your cannabis seedlings and reduce the moisture gradually until the plant is ready for harvest, where the humidity should be around 40%.

Luckily, humidity levels in cannabis growing spaces can be detected easily using manual or automatic hygrometers. If your cannabis plants are in a grow tent, there is also an advantage of automatic reduction of humidity levels. Commercial size dehumidifiers and fans are used for this purpose.

15 comments

Unless you have your exhaust fan fill force but in a 4 × 4 I have been advised and successful opening a single vent, keeping 6″ Infinity at 3 max and still get the right amount of negative pressure. I think a full on carbon filter is waist until flowering, but that’s me. I use a small washable filter with mesh wraps. When plants in full flower at 2nd – 3rd week I open a 2nd vent…the 1st opposite the exhaust and the 2nd on a perpendicular wall. Never the wall by the exhaust. That’s also when I install the AC Infinity Carbon filter. I also learned to only use a 0ppm water, R/O or distilled or Pure water from discount store. Measure the PPM because of it has any you can bet it’s cal Calcium…many people think the have PM but plants don’t care for it either. These are suggestions from my initial errors

As with any 60+ humidity loving plant, just spray the covering, inside growth and especially outside growing early. Always try and cover early plants, late plants need more air flow. Keep the humidity up early and your usually on the money.

If your using a tent I found soaking grouting sponges and leaving them in the tent to raise humidity. Rather than a bowl of water.

I run an AC inline fan with temp/Humidity control in a 5×5 tent. You have to find that sweet spot especially when your lights go out for the dark period and often its a day to day adjustment on fan speed and heater temp. My tent is in the garage and I’m currently in veg stage so those garage temps also affect the adjustment.

Automation is the answer to proper temp & humidity control. Environment is important but always remember, it’s a weed, it’ll grow given a chance.

Temperatures and Medical Cannabis Growing: From Seedling to Harvest

The marijuana industry created an estimated $34 billion economic impact in 2018. Legal sales of marijuana are expected to increase from $10 billion in 2018 to $20 billion by 2022, according to the Marijuana Business Fact Book. This means that more and more legal growers (under strict governmental regulations) will be on the American horizon seeking the best indoor growing practices. Temperature and humidity monitoring are essential for growing healthy cannabis plants throughout the entire life of the plant…seedling to harvest.

What’s the Difference Between Temperatures and Humidity Levels?

Temperature and humidity levels interact and are very similar and are closely related to one another. Humidity is the measure of how much humidity is actually being held in the air. Relative humidity (RH) which is one way to measure humidity levels, is how much water is in the air compared to the maximum amount of water that can be held in the air at that temperature. The premise is that warm air holds more water vapor than cold air so it is important to get the warmest air in the environment. It is necessary to extract the warmest air from the growing environment while allowing cool air to enter. The warm air alone has way too much vapor for ideal growing conditions.

Horticulturalists know that the key to success in any growing plant is understanding the lifecycle of the plant. This is also true with growing cannabis. Throughout every stage of growth, cannabis plants will have a constant need for water which the amounts will fluctuate with the humidity. When the humidity is high, plants use their leaves to absorb moisture from the air which results in less water drawn from their roots. On the other hand, when the humidity is low, cannabis plants will take more water through their roots.

Monitoring and having the right humidity encourages strong, healthy, nutrient-dense leafy plants with optimal growth.

Humidity levels must be monitored to prevent:

1. Bud Mold/Rot: A condition when the inside of the plant is taken over by mold. When this happens the buds are unusable.

2. White Powder Mildew: White Powder Mildew (WPM) is a rapidly reproducing fungal disease resulting in a white powder or mildew covering the plant. If caught early enough, it can be prevented, if not the plant will become unusable.

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3. Nutrient Problems: If a cannabis plant takes in too many nutrients at once the leaves will turn yellow and the tips will look burnt, called nutrient burn or nute burn.

4. Slowed Growth: If humidity levels are not optimal for the growth stage, they don’t grow as fast as they could. Younger cannabis plants grow better in higher humidity than more mature plants.

So, the next question is how do you measure the ideal levels?

Cannabis Temperature Monitoring In All Stages of Growth

There are four stages or periods of cannabis growing, all requiring different temperature and humidity levels. They are seedling, vegetation, flowering, and late flowering. Experts recommend monitoring levels throughout all four stages using a digital thermometer and a digital hygrometer that include a memory feature so history can be reviewed. The four stages and what they require are:

1. Seedling Stage: Seedlings or clones, little cut-off pieces from a parent plant that needs to develop roots, require high humidity levels between 65 and 70 percent. These high humidity levels are needed because the root system is not established and humidity allows water intake through the plants’ leaves. Young growing cannabis plants prefer temperatures between 75 and 80 degrees Fahrenheit. Anything above 80 degrees Fahrenheit is not recommended.

2. Vegetation Period: This is the stage that cannabis starts developing its renowned leaf shape. It is important to note that light exposure is a very important part of this stage. The number of humidity levels should be lowered by five percent each week throughout the vegetation period. The temperature can be increased, too because roots absorb more water and evaporate through the plants’ leaves. Humidity levels should be before 40 and 70 percent. If wet spots are forming on the leaves, humidity levels are too high.

3. Flowering Plants: The humidity levels of cannabis plants at the beginning of the flowering stage should be lowered to 40 to 50 percent. At this stage, the plants have created a robust root system to meet their water needs. They still absorb water through the leaves. A lower humidity level is required to prevent mold and mildew from forming. Note that mold and mildew infect the plant from the inside the buds, so it isn’t visible at first.

4. Late Flowering Period: This period lasts anywhere between six and 12 weeks and when plants mature. During this time careful temperature and humidity monitoring are necessary. It is recommended that humidity levels be lowered between 30 and 40 percent to improve the yield, flavor, and appearance of the plant. Temperatures can range between 70 and 80 degrees Fahrenheit.

Tips To Adjust Temperature and Humidity for Cannabis Growing

It can be difficult to keep humidity and temperature levels at the right balance throughout the plants’ life cycle. Keep in mind that warm air retains more water than cold air and that relative humidity and temperature interact to create the perfect balance. The following are hands-on tips for adjusting these levels but note that there is technology available in the SaaS Cloud that will wirelessly do the work for you.

Tips to Lower Humidity and Temperature:

  1. Increase fresh, cool air in the growing area
  2. Water plants right when lights are turned on in the growing area
  3. Add a dehumidifier to regulate humidity in the growing area

Tips to Increase Humidity and Temperature

  1. Keep the soil surface moist
  2. Surround the room with moist towels and open containers of water
  3. Use a humidifier to constantly add moisture to the room

It is difficult to be present for the entire life cycle of a cannabis plant. There are more innovative and technological methods for monitoring temperature and humidity levels. Contact SensoScientific for a free trial and to learn more about the most advanced wireless monitoring solution available for cannabis temperature monitoring.

How Long to Germinate Weed Seeds?

In order to produce marijuana buds, the cannabis plant needs to go through 4 growth stages like the germination stage, the seedling stage, the vegetative stage, and the flowering stage. For the purpose of simplifying the process of cannabis cultivation to our readers thinking about becoming marijuana growers, in this article we’re focusing on the germination stage and how long it takes to germinate weed seeds.

Germination, or sprouting, is the first stage of cannabis cultivation during which the cannabis seeds are placed in water in order to develop sprouts. Some marijuana seeds may germinate while others won’t, and the sprouting success rate mostly depends on the quality of the seeds.

In order to increase the germination rate of cannabis seeds and increase the chances of successful germination, check out our guide below.

The 411 on Germinating Marijuana Seeds

Before you start cannabis cultivation and germinating seeds, you will definitely benefit from reading the following tips:

  • Purchase high-quality seeds from a verified seed bank.
  • Purchase growing lights required for the following stages like LED, CFL, or HID grow lights.
  • Use a heating pad underneath the seeds to help aid germination and maintain proper temperatures.
  • Pre-soak seeds in 1% hydrogen peroxide or compost tea for 12 hours in order to improve germination or kill pests.
  • Keep the marijuana seeds under a temperature of about 72 degrees Fahrenheit (22 °C).
  • Keep the seeds away from your windows and direct sunlight.
  • Purchase jiffy pellets or starter plugs for germinating weed seeds.

How Long Do You Need to Germinate Cannabis Seeds

The time needed for seeds to sprout is not always the same, but if you’ve provided your cannabis seeds with the right conditions, germination should usually start between 12 to 36 hours after you’ve soaked the seeds. Warmth, moisture, and darkness will accelerate cannabis seed germination, and the whole process can be over within 5 to 10 days (during which the seeds will be completely out of their shell). The more ideal your germination environment is, the faster your cannabis seeds will start to germinate.

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Choosing a Germination Method

There are a few ways that you can germinate your seeds and the most common ones include:

  • The paper towel method;
  • The glass of water method;
  • Planting directly into the soil.

The Paper Towel Method

This germination method is one of the easiest ways to germinate seeds and it only requires paper towels soaked in tap water. The two pieces of paper towels are soaked in water, and the cannabis seeds are placed between the sheets. Additional water should be added so that the seeds are moist, and excess water should be drained away. Furthermore, the temperature in the area where they’re kept should be between 70-90°F (21-32°C).

Once the seed splits and a sprout appears, you’ll know that the seed has started germinating. The sprout is called the taproot, and it’s a sign of successful germination. After the seed starts to split, make sure you’re very careful with the taproot when planting it, and don’t touch the seed as it begins to split.

The Glass of Water Method

This is the most common germination method for beginner growers since all it takes is placing the seeds in a glass of water. The seeds should be placed in a half-filled glass of water at a temperature of about 71°F (22°C), and the seeds will start sprouting between 3-5 days and develop taproots. After the roots reach 2–3 mm they should be transferred to soil pots, and over time the germinated seeds will develop into cannabis plants.

Keep in mind that not all seeds will germinate. Some seeds will sink to the bottom and some will float. The ones that float are probably not viable, and they need to be thrown away. Use tweezers when transplanting the taproot into a growing medium, and start preparing the proper lighting system for your marijuana plant.

Planting Directly Into the Soil

This germinating technique isn’t recommended for beginner cannabis growers since they need to be informed about the proper nutrients, appropriate pH soil, and humidity levels that the growing medium should have.

What you’ll need in order to plant directly into the growing medium are pots filled with premium-quality soil that’s been soaked in water. This method of germinating cannabis seeds prevents moving the seeds when they’re at their most fragile state, and that’s exactly the reason why most experienced growers prefer it.

What to Avoid When Germinating Cannabis Seeds

If you are planning to grow your cannabis plants from seeds and germinate them, you’ll need to avoid some common mistakes that cannabis growers make.

Letting the Germination Medium Dry Out

While germinating, always make sure that the paper towels stay moist. This is especially important if you have a heat source placed above the germinating seeds. It’s better to opt for rock wool cubes germination as opposed to hydro since it helps retain moisture.

Avoid Overwatering

Overwatering your cannabis seed may result in bud rot and ruin the potential for the cannabis seed to grow into a cannabis plant. Make sure you provide your plants with enough water, but not excess water.

Avoid Leaving Seeds to Germinate Longer Than They Should

If you end up germinating using the paper towel method, make sure you leave the seeds to germinate, and transplant them before the cotyledons appear. The best time to transplant is once the taproot is between 1-2 cm in length.

Do Not Germinate Directly in Soil

If you’re a less experienced grower, don’t start by germinating in soil. You could always try germinating using the paper towel method, jiffy pellets, or peat plugs, which will make it easier to maintain proper temperature and humidity.

Maintain the Appropriate Temperature and Humidity for Germination

The right environment is essential for successful germination. Ideally, the germination medium should have a temperature of about 72 degrees Fahrenheit (22 °C) and 70% relative humidity. Lower values may make the germination less successful, while higher values might result in rot or fungus.

Plant the Seeds Correctly

The seed needs to be planted with the root facing down, so when it opens at the tip it lets out the root. The seed shouldn’t be buried too deep because the seedling may never emerge, or, on the other hand, if it’s too close to the surface, the stem can grow weak. Make sure that the top of the seed is just below the surface of the growing medium, and the root faces down.

Final Thoughts and Transplanting Germinated Cannabis Seeds

After the taproot appears, you can transfer your germinated seed into a growing medium and wait for the three stages that follow in the marijuana growth cycle. You can choose to grow in coco coir, hydroponic, or soil, depending on your preferred planting medium. Young plants are pretty vulnerable, which is why you should be extra careful when transferring them in the potting soil. As you grow more cannabis plants, you’ll learn more about the germination process, which will make you more confident each time you germinate new seeds.

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