You don’t need to put down your garden shears and your green thumb just because it has snowing outside. You just need to take the weed garden indoors! Is it possible to grow winter marijuana seeds? Here're features and tips for a perfect harvest. >> Read the article! Seasons and seeds: what are the characteristics of the auto-flowering winter seeds. >> Click here and read the article!
How to Grow Cannabis in Winter
If you think that growing cannabis in a European winter is impossible, then you’ve been misinformed. With the right conditions in an indoor growing operation, you can successfully yield good quality cannabis. We are here to teach you how to set up and optimize your grow room in the winter time.
When growing cannabis in winter, even an indoor garden is at the mercy of the elements. Cold, dry air and dropping temperatures can create problems with relative humidity and light intensity. But that doesn’t mean that growing in winter is impossible. Actually, with the right conditions, an indoor garden can perform just as well in winter as it does in the summertime.
It is true that growing in the winter takes a little more attention and a little more TLC. With the right advice and the right frame of mind, you can successfully grow all year round. That is what we are here to help you do!
How to maintain grow room temperature in winter
Temperature is one of the most important concerns when growing in the winter. Optimal daytime temperature for cannabis is 24-30°C (75-86°F), and optimal night-time temperatures falling in the range of 18-22°C (64-72°F).
As a grower, you want to avoid temperatures outside of the prescribed range but you also want to avoid huge discrepancies between day and night temperatures. Growth rate is severely affected by inconsistent temperature changes as much as by an incorrect temperature bracket.
As well as this, if there is too great a discrepancy between daytime and night-time temperatures in the first 2-3 weeks of the flowering period (during which time plants ‘stretch’ noticeably), very widely-spaced internodes will result. Conversely, keeping the discrepancy as small as possible throughout this time reduces the space between nodes.
A temperature gap of 2-4°C (3.6-7.2°F) is ideal for the first 2-3 weeks of flowering. A gap of no more than 10°C (18°F) should be maintained for the rest of the flowering period.
If you are an old-school cannabis grower, then you probably love growing in the winter. That is because last decade’s HID (high-intensity discharge lightning) technology emits alot of heat. And if you are using them in the summer time, then you need to pay through the roof for air conditioning. But in winter, HID lights can keep your grow room at the optimal temperature.
With that being said, a temperature drop when the lights are turned off is something to think about. To mitigate this, winter growers use their lights during the night time and use daytime as the lights off period. This lets a grower take advantage of warmer temperatures during the day.
While daytime temperatures are higher, they are not always high enough to maintain the plants’ required ‘night-time’ temperatures of 18-22°C (64-72°F). If temperature is consistently dropping below this range when lights are off, it is advisable to use central heating or an electric heater to maintain adequate temperatures.
A digital thermostat will come in handy here to automatically control the heater according to the ambient temperature. If using cold lights such as LEDs, heaters may be required round-the-clock.
Controlling humidity of cannabis grown in winter
Mould is one of the biggest threats to your cannabis garden during the winter. In the winter, there is a tendency for low temperatures to increase relative humidity (RH) to a point of danger for your plants. Not only do cannabis plants detest high levels of relative humidity, but it also makes them a breeding ground for mould and fungi. Low temperatures can create issues in maintaining relative humidity.
Essentially, the volume of water in the air continues to condense as the temperature drops. And if you have ever grown cannabis before, you know that this can open up a proverbial can of worms (or better yet, mould) all of your plants.
The obvious way out of this problem is to keep temperatures at the optimum level, whether by using lights or by using central heating. If the problem is extremely hard to contain, then it may be necessary to use a dehumidifier.
It is also highly recommended that winter growers purchase a device called a hygrometer. This device can test the relative humidity of your soil as well as your grow room. It is essential to regularly measure the relative humidity in order to stay on top of it and avoid huge spikes or drops in the concentration of water in the air.
In many areas, winter is actually the driest time of the year, as well as being the coldest. If you are not facing issues of relative humidity, then cold dry air will present problems of its own in the grow room. If air is taken in from outside at a temperature of 10°C and an RH of 50%, it will contain water vapour at 4.7g/m³. If this air is heated to 25°C without the addition of extra moisture, its RH will drop to around 20%, which is far too low for healthy cannabis plants to grow.
In the growroom, a moist growing medium along with transpiration will generally raise levels of water vapour in the air. However, relative humidity should remain consistently between 40% and 60%.
Other things to consider when growing in winter
Temperature and humidity are the main issues that winter-time growers will have to deal with. Lighting is usually not an issue as plants are typically grown under HID lights.
Having said that, some hobby growers might still be eager to utilise as much natural sunlight as possible, such as growing on a windowsill. The problem with this is that light intensity or simply the amount of sunlight hours may be insufficient for growth. Each area will vary in its wintertime habits, and each grower should make choices accordingly.
Some clever growers will use extra lighting during winter only, to ensure that their plants have enough light to grow. While plants will usually not achieve the yields and qualities achieved in more favourable times of the year, there are plenty of smart hobby gardeners out there that will ensure their supply remains steady even in the harshest times of the year by following this principle.
Greenhouse growers are similarly affected by the reduction in daylight hours during winter, and unlike those growing on their windowsill at home, additional lighting may attract unwanted attention.
However, some adventurous greenhouse growers will add the supplementary lighting and then make sure that the greenhouse is covered so that light does not escape when it is dark outside. Thick, heavy blackout curtains or Mylar sheeting can do an excellent job here. Then, all that remains is to heat the greenhouse sufficiently and provide adequate airflow, and growing throughout the winter should become possible.
Top 10 Craziest Hidden Cannabis Grow Rooms
Consider growing winter-appropriate strains
Every grower understands the temptation of growing their favourite strains throughout the winter, even if those strains aren’t really appropriate for winter growing. If you can let go of that temptation and choose winter-appropriate strains, you might be able to avoid some of the difficulties in growing over a snowy winter.
Let’s look at autoflowering strains as an example. In as little as 8 weeks from germination of the seed, you can have a ready-to-harvest cannabis plant. This means that a grower can avoid growing throughout the harshest part of the winter and maximize their growing opportunity.
Any strain that contains ruderalis genes is also more likely to make it through a winter. Ruderalis is tougher and hardier than more common strains. It also isn’t photoperiod dependent, meaning it will flower when it’s ready rather than as a response to a change in light hours. It can bloom within 30 days of planting.
Growing in winter might mean doing some additional planning in advance to prevent the demise of your plants. But that doesn’t make it impossible. After a couple of seasons growing weed in a snowy winter, it should start to feel like second nature.
Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.
Winter marijuana seeds: features and tips for a perfect harvest.
As the cold season approaches, cannabis growers tend to wonder what the winter marijuana seeds are, so they have a fair chance of harvesting them during the winter as well.
It is said that auto flower seeds are best for outdoor winter, as they have – at least partially – Ruderalis genetics. And Ruderalis cannabis reflects what the name makes us imagine: it is ‘rough’, wild, used to survive even under extreme conditions such as cold, rain and high humidity.
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The belief that auto flower seeds are perfect for withstanding extreme temperatures and weather conditions is not entirely wrong, but the farmer’s final goals must also be considered. Are you only interested in a strong cannabis plants or are you looking for a good harvest? If the latter option is the right one, maybe you should not grow outdoors.
Please note that our in-depth studies are only for information. We do not advise you to grow weed seeds because, if you are in the UK, you will commit an administrative or criminal offence depending on the situation. If you currently live in a state where it is allowed to grow marijuana for personal use, then you can rest assured.
Do winter cannabis seeds have a good yield when grown outdoors?
The answer to this question is no! Marijuana plants need special conditions to develop and flourish at their best.
Although automatic cannabis strains flower not according to temperature and light conditions but according to their age (they are usually ready for harvest about 10 or 11 weeks after germination). If grown outdoors in the middle of winter they may still die or stop growing. At best, they may produce very few flowers with low THC and CBD content.
Now imagine you are a cannabis grower. After you have put all your energy into getting a beautiful plantation, winter comes to stop everything: no crops and seedlings irreparably damaged. It’s certainly not a pleasant prospect!
Growing marijuana seeds on winter is undoubtedly possible, but not outdoors. For marijuana plants to develop outdoors in the best possible way, they need favourable climatic conditions.
The perfect conditions for cannabis plants development
Marijuana doesn’t care whether it’s summer or winter. It is only essential to have the right climatic conditions for its growth. For auto flower seeds, fast growing weed seeds and feminized seeds to germinate and for the seedlings to grow well, it is essential that the following conditions are met:
- Relative humidity: during germination, the RH should be between 60% and 80%, during the vegetative phase the RH should be between 50 and 70% and during flowering between 40 and 60% at most.
- Temperature: the temperature should be reasonably stable, so a wide temperature range is not recommended. During the germination of cannabis seeds, the temperatures should be between 22 and 26ºC, during the vegetative phase between 21 and 29ºC and during flowering between 18 and 26ºC. The minimum values refer to night-time temperatures, which should not exceed 6-7ºC difference from daytime temperatures.
- A good soil, well-drained, fertile and fertilized with organic nutrients.
Read the following article to learn more: How to sow marijuana in the best possible soil: 5 things you don’t know about the relationship between soil and germination.
That said, minimum temperatures should never drop below 15ºC as cannabis plants could suffer so much, stop growing and/or die. As you can imagine, it is complicated for temperatures not to fall below 15ºC in winter (unless you are in the Maldives, Hawaii or somewhere else where it is hot all year round… So I envy you!).
Besides, it is not uncommon for rainfall, frost and other situations to occur during the winter months. They will be the perfect conditions for mould and fungi development, which are very harmful to cannabis plants.
That is why growers who choose to plant cannabis seeds in winter do so Indoor or in Greenhouse.
Do winter marijuana seeds exist?
Let’s say that plants born from auto-flowering cannabis seeds and fast growing cannabis seeds are more resistant to low temperatures than seasonal plants. They come from Cannabis Ruderalis varieties crossed with Indica or Sativa. But don’t expect them to resist frost and extreme temperatures!
They may not die below 15ºC, but they will still suffer, either by stopping growing or at most producing a small number of flowers. That’s why growers prefer to grow Indoor or Greenhouse with controlled temperatures, in order not to stop during the winter season and get a good harvest.
Alternatively, if they are in a region with an extremely favourable climate, they can grow in pots and then you only have to shelter them during the evening, at night, and when the weather conditions turn bad.
Since we’ve talked so much about auto-flowering varieties, you might want to add these seeds to your collection… Then visit our catalogue and buy the best weed Seeds BSF, autoflowering, feminized and fast growing weed seeds!
Seasons and seeds: what are the characteristics of the auto-flowering winter seeds.
Everything you need to know about winter autoflowering seeds.
As you may know, marijuana seeds are not all created equal. You will find the standard ones, the feminized seeds, but also the auto-flowering and fast flowering seeds, from which ultra-fast flowering plants are born. However, all seeds tend to generate plants that love temperatures between 20 and 28ºC.
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Farmers who want to perfect their cultivation should know that not all cannabis plants will survive the very harsh winters, typical of continental climate regions or mountain areas. However, some resist well even at low temperatures. These are the plants born from the so-called “winter auto-flowering seeds“.
What is a winter auto-flowering seed?
In reality, there are no winter cannabis seeds, but rather seeds from which the seedlings are very resistant to low temperatures. These plants are the auto-flowering ones.
There is a particular reason why the minimum temperature for auto-flowering plants could even drop below zero without serious repercussions. They come from the mixture between Indica or Sativa plants with Ruderalis cannabis plants. In general, the Indica / Sativa are feminized. Therefore, the hemp seeds that derive from them can produce 99.9% of the female plants.
Ruderalis is the “wildest” strain, which adapts to different temperatures (and that can also resist well to the attack of parasites) as they mostly grow in areas such as Eastern and Central Europe. Perhaps it will not be a surprise to you to know that Ruderalis also grows in Russia, where the average summer temperature does not exceed 19ºC, and where the winter drops many degrees below zero.
But resistance to cold temperature is not the only peculiarity of plants born from auto-flowering marijuana seeds.
Characteristics of autoflowering cannabis plants.
Autoflowering plants are often appreciated by gardeners who do not have a vast space or a large greenhouse and who do not need a tremendous yield in terms of flowers.
The reasons are found in the characteristics of these plants. Here is what distinguishes autoflowering:
- Short stature (often referred to as “dwarf auto-flowering”). For this reason, they can be both in small portions of land or in small greenhouses.
- Resistance to pests and unfavourable climatic conditions. Therefore, those who can cultivate these seeds can choose whether to do it Indoor or Outdoor (we remind you that in the UK, the germination of seeds is prohibited, while it is possible to buy auto-flowering, feminized and/or fast flowering collection seeds).
- Auto-flowering is independent of the seasons. It means that these plants bloom according to their age and not according to the photoperiod (as opposed to standard plants, which are seasonal).
- Very short flowering and ripening times. Flowering often begins just 2 to 4 weeks after germination, and marijuana buds ripen before 10 weeks.
- Average-low yield: you only have few branches with auto-flowering plants, precisely because of the small stature of the stem. Consequently, the number of flowers issued from dwarf-autoflowering seeds is also lower than in standard plants.
Autoflowering plants are ideal for both indoor and outdoor cultivation, and due to their very resistant nature, they also grow well during the winter. Some can even support -15ºC, but we doubt that farmers risk exposing them to such a temperature.
Growing cannabis plants, even autoflowering ones, with very low temperatures entails disadvantages.
The cons of outdoor cultivation in winter.
Although auto-flowering plants can adapt to the most varied climates, it does not mean that they grow and produce the best, even if subjected to very harsh environments. Usually, those who grow auto-flowering winter seeds outdoor choose to do it in pots, so that they can shelter the plants in case of unfavourable weather conditions.
It is not only necessary to consider the temperature resistance, but also the yield of plants and other factors that could damage it.
An auto-flowering cannabis plant subjected to low temperatures could slow down its growth cycle and generate much fewer buds than expected. Consequently, the production of inflorescences would be compromised.
It is not only due to the cold temperature, but also more or less intense rain, wind, hail and frost—all of these things that will irreparably damage a cannabis plant, even the most resistant.
The ideal solution during the winter (in countries where cannabis can be grown, therefore not in the UK) would be to choose a greenhouse or pot cultivation. In the latter case, farmers must be cautious about the plantation, as well as have the space in which to transport and store the pots during heavy rainfall, frosts and strong winds.