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 Cannabis seeds need only water, heat, and air to break dormancy and germinate; they do not need extra hormones, fertilizers, or additives. Seeds sprout Without a doubt, germination is one of the most important stages in cannabis cultivation. In this article we will take a look at some of the most comm
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.
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:
- Increase fresh, cool air in the growing area
- Water plants right when lights are turned on in the growing area
- Add a dehumidifier to regulate humidity in the growing area
Tips to Increase Humidity and Temperature
- Keep the soil surface moist
- Surround the room with moist towels and open containers of water
- 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.
Jorge’s Cannabis Encyclopedia: Seed Germination
Cannabis seeds need only water, heat, and air to break dormancy and germinate; they do not need extra hormones, fertilizers, or additives. Seeds sprout without light in a range of temperatures. Strong, viable, properly nurtured seeds germinate in 2 to 7 days. At germination, the outside protective shell of the seed splits, and a tiny, white sprout (radicle) pops out. This sprout is the root, or taproot. Cotyledon, or seed, leaves emerge on a stem from within the shell as they push upward in search of light.
Break dormancy: Put newly harvested seeds in the refrigerator for a week or two to simulate winter. Remove and germinate. Seeds will germinate more uniformly because they all come out of dormancy at the same time.
Timeline for Germinating Most Seeds:
At 36 to 96 hours – Water is absorbed, root tip (radicle) pops through outer shell and is visible.
At 10 to 14 days – First roots and root hairs become visible.
At 21 to 30 days – At least half of seeds are rooted by day 21. Seeds not rooted by day 30 will probably grow slowly.
Once seeds are rooted, cell growth accelerates; stem, foliage, and roots develop quickly. Seedlings develop into full vegetative growth within 4 to 6 weeks of germination.
Seeds are Prompted to Germinate By:
Water: Soaking seeds in water allows moisture to penetrate the protective seed shell within minutes. Once inside, moisture continues to wick in to activate the dominant hormones. In a few days, hormones activate and send enough signals to pro- duce an initial root tip. The white radicle (rootlet) emerges to bring a new plant into the world. Once a seed is moist, it must receive a constant flow of moisture to transport nutrients, hormones, and water so that it can carry on life processes. Some seeds need lots of moisture to wash out the dormancy hormones in the seed coat, and if they do not get enough moisture, they do not germinate. Conversely, too much water deprives the seed of oxygen, reducing its quality or destroying it. If fragile germinated seeds are allowed to suffer moisture stress now, seedling growth will be stunted. Soaking most seeds in water for 12 to 24 hours is all they need to initiate germination. All the nourishment for a seed’s initial growth requirement is pulled from the fleshy cotyledons, or seed leaves. Water seedlings with low-EC (electrical conductivity) household tap water during the first week or two of life. Supple- mental nutrients are unnecessary and if applied in excess can disrupt internal seed chemistry. Some gardeners prefer to germinate seeds using distilled or purified water that contains virtually no dissolved solids.
Temperature: Overall, cannabis seeds germinate in temperatures from 70°F–90°F (21°C–32°C) and grow best at 78°F (26°C). Temperatures below 70°F (21°C) and above 90°F (32°C) impair germination. Low temperatures delay germination. High temperatures upset seed chemistry causing poor germination. Seeds germinate best under the native conditions and temperature ranges where they were grown.
Air & Oxygen: Sow seeds twice as deep as the width of the seed. For example, 0.125-inch (3 mm) seeds should be planted 0.25 inches (6 mm) deep. Adequate oxygen is un- available for seeds planted too deeply, and tender seedlings have insufficient stored energy to drive through deep layers of soil or crusty hard soil when sprouting.
Agricultural Astrology — Planting by the Moon
Ancient Babylonians and Egyptians planted and harvested based on moon phases in relation to geographic location. The premise is that plants grow better when planted during the appropriate moon phase.
Moon phases cause ocean tides to rise and fall. They also affect the rise and fall of moisture in soil and fluids inside plants. The moon phase influence is said to be the same indoors, outdoors, and in greenhouse-grown cannabis.
Cannabis gardeners who plant by the moon report faster-sprouting seeds that grow into vigorous plants. However, scientific evidence is lacking in regard to cannabis and other plants’ relationship with agricultural astrology.
Seeds need oxygen from the air to germinate. Growing mediums that are too moist (soggy) will cut off oxygen supplies and the seeds will literally drown. Cannabis seeds germinate best when moisture is between 60 and 70 percent.
5 common mistakes when germinating cannabis seeds
Although the germination of cannabis seeds is a relatively quick and easy process, it is crucial to take into account a series of important factors in order to obtain as high a germination rate as possible. In addition, it’s in our interest that the seeds germinate as quickly as possible, and especially if we want to avoid problems like fungal infection or a low germination rate.
In our article on how to germinate cannabis seeds we explain step by step what you must do to achieve successful germination. Today we will take a look at the main mistakes made during this process, some simple errors that, as we will see, can easily be solved. Let’s see where many growers fail to germinate their seeds, it’s a great way to learn what not to do if we want to make the most of our seeds.
A germinating cannabis seed
Letting the germination medium dry out
By placing the seed in a moist culture medium, it begins a series of reactions that will lead to germination in a few hours or days. Whichever substrate we choose for germination, we must ensure that it never completely dries out, because as the seed stops absorbing moisture, it’s likely that the seed will cease its activity and never germinate. Cialis for Erectile Dysfunction http://valleyofthesunpharmacy.com/cialis/
For this reason, it is advisable to check every day to make sure the germination medium remains moist, especially if a heat source is used to achieve a higher temperature and therefore a better germination rate; the heat will cause the substrate to dry more quickly, something that must be kept in mind to avoid nasty surprises. In case of hydroponic cultivation it is always better to germinate in rock wool cubes, which of course must always remain moist.
The paper towel should never dry out once germination begins
Leaving seeds to germinate for too long
Another common mistake, in this case when germinating in kitchen paper or similar, is to let the seed germinate until the cotyledons appear. If we do this, then the subsequent transplant is very difficult, and it is very likely that we’ll damage the root in the attempt. Additionally, the longer the root is exposed to air and light, the more damage will result, so it is preferable to transplant it before this occurs.
To avoid problems, it is best to plant the seeds when the tap-root measures approximately 1cm, or 2cm at the most. This will make it much easier to transplant and we won’t harm the development of the roots, which can be expand into the new growing medium without setbacks. Phentemrine diet pills http://kendallpharmacy.com/phentermine.html
Direct germination in soil
This is a common mistake that usually results in non-germination, especially if the substrate hasn’t been previously watered before sowing the seed but is watered afterwards. By planting the seed directly in the substrate, we run the risk of it being buried too deep, made worse when we irrigate the growing medium post-sowing.
To obtain much better results, first germinate seeds in kitchen paper, jiffy pellets or peat plugs used for rooting cuttings and then transplant them to the soil or to a pot once the small seedlings have been born. Another benefit of this method is that we can germinate a large number of seeds in a very small space, such as a small greenhouse, which will make it much easier to provide the correct temperature and humidity.
Temperature and humidity for germination
Cannabis seeds germinate correctly with relatively high temperature and humidity values. It will be necessary, especially during some seasons of the year, to use some source of heat to get a temperature of about 26-28ºC. For this purpose there are many options on the market, such as thermal cables or heated greenhouses. The latter are particularly interesting because they also provide the perfect high humidity environment for seed germination.
The ideal is to maintain the germination medium at about 26-28ºC and at 70% relative humidity. Lower values will result in a slower and less successful germination, while higher values can bring fungal or rot problems.
A heated greenhouse is perfect for germinating seeds
Planting the seed incorrectly
If you look closely at a cannabis seed, you will notice that it has a slightly oval shape, ending in a point at one end and forming a small “crater” at the other end, which is called the crown. When planting your seed (whether it’s a seed that you want to germinate, for example, in a jiffy, or a seed already germinated on kitchen paper that you want to transplant) you must keep in mind that this crown should always be facing upwards.
So, you should plant the seed with the tip down and the crown uppermost and facing you. Once the seed germinates the crown will serve as a hinge, so that the seed will open at the tip and let out the root. In case of placing the seed incorrectly, the tap root will grow upward and the seedling downwards, which should be avoided at all costs because it is likely that the seedling will not be born.
Planting at the incorrect depth
Too often the seed is buried too deep (a problem that we have already seen in case of watering after planting the seed), so the seedling may never emerge. In the other case, if we sow too close to the surface, we can find that the seed germinates well but the stem grows weak, bending and not allowing the seedling to develop correctly.
To avoid these problems it is be best to sow the seed at about 2cm depth. In addition, we can cover the lower stem as the seedling grows, so that it gains stability and produces new roots along the length of stem we have buried. In this way we can accelerate the growth of the plants.
We should plant the seed with the root downwards
Planting several seeds in the same pot
Although it may be tempting, germinating several seeds in the same container is not usually successful. In addition to the difficulty of correctly planting several seeds in the same pot, once they are born they will compete for the little space available for their roots. Having restricted root growth does not suit cannabis plants, which will grow more weakly and with greater internodal distance.
In addition, the scarce space between the plants will also mean they will compete for available light, something not recommended if we want to get the most out of each plant. The plants will produce very little lateral branching, and will center their growth on a weak main stem, with too long an internodal distance, factors that usually affects negatively on the final yield of buds.
We hope that this article will help you avoid problems when germinating your seeds, it can be very frustrating to start a grow with all the enthusiasm and excitement, only to run into problems straight away! Do not hesitate to leave us any doubts, comments or your own tips and tricks, we’ll be happy to answer you.
Comments in “5 common mistakes when germinating cannabis seeds” (49)
I’ve been growing since I was 13. I am 66. Not a boast. It just is. My comment is not so much about growing weed but rather about a lack of civility AND (not necessarily limited to only this forum). For the most part cannibis “enthusiasts” are wonderful people. Still, is it my imagination or are there a lot of condescending pricks (can I say that?) on these forums. Some of which are “Newbee Experts” criticizing anything that didn’t come out of their own mouths? When the Real Expert offers an opinion that doesn’t mesh with the self proclaimed genius’s vast knowledge base, they tend to respond with very little grace. So I guess this is more about the general state of things and what some people believe is acceptable behavior. Just a thought. Cannabis community, let’s treat each other with respect. We’ve made so much ground and it’s taken SO MANY years. Let’s not screw that up.
Just a quick poll for those of you with a few growing seasons under their belt. Have you found that your failure rate with seed germination has been increasing. I suppose it is possible that I’ve just had a bad run but my success over the last two grows has been about 50%. I’ve been doing this stuff for a long time and my technique is sound. Just seems like I have more duds lately (I have not purchased seeds from Philosofer).
I quit reading long back when the initial 100 seed results were reasoned. I’ll likely be missing many points observed. Simple opinion, for better than 25 million years of natural survival this plant has recreated itself for man to adapt to its uses in a very short 10,000 or how ever many years there’s been somebody crapping In a watermelon patch Surely it knows its way around a 2cm [email protected]&?ing hole surrounded by its predecessors environment. I would think genetically it knows what the !(@& to do. Especially if you are using a “Feminized seed”. Now, surely many observations have been made justifiable or not the laws of average are easily debatable, but I believe that the laws of average have established the standards many moons ago friends. Maybe I’ll fill up a kiddie pool 4ft Dia. @6 inches deep perlite and drop a 100 seeds through a pine bow from 6 feet high and then document the seeds position when it’s at rest in the perlite.. . I’m Extremely new to cuktuvating cannabis, my 2nd year. My first year turned out peesonally satisfiable at best simply because I planted shark cookies. I germinated in a paper towel, from there I rested the seed however it rested in a tub of perlite with an aquarium bubbler, also a circulator moving a solution of compost tea through the roots for 2 weeks, then put them in a small crawl area with a fan and a few lights for another 45 days, and then moved them to a bucket and put outside for the next 3 months and then brought back inside for another 2 weeks. So any opinions that we all have are open for discussion, but the only resolution for judgement is our own environmental abilities to nurture the development of variable genetics. Happy gardening friends..
Hi and thanks for your comment. We’re happy that your first year of cultivation was a reasonable success, we hope that this year will be even more so! Germinating seeds may seem like the most natural and easy thing in the world, and that’s how it should be, but it’s amazing just how many people fall at this first hurdle, and when the seeds are not particularly cheap, as in the case of cannabis, it becomes even more nerve-wracking, especially for beginner growers and those who have no basic experience of growing other plants like vegetables, flowers, etc. There’s no real substitute for experience in this game, and the more seeds we pop, the more confidence we get. Thanks again for your comment, best wishes to you!
Hello Good day I have some that looks like stale might be more than years old seeds. It was a given to me by a friend and I doubt it was preserved properly in proper containers. Will it still germinate?
Hi, thanks for your comment and question. The older the seeds are, the less chance they will germinate, and if they weren’t stored in good conditions (dry, cool, stable, e.g. in the fridge) then the chances of non-germination become even greater. You can try a few things to help improve germination rates, for example, the application of fulvic acid and/or gibberellic acid will give older seeds a better chance of germinating. Try germinating a few of the seeds in the normal way and then if you don’t get success I’d look at using one or both of the compounds I mentioned. I hope that helps, all the best!
I have germinated five seeds of different stains, all paper towel method. All sprouted.. All healthy.. All put in good seedling raising mix but the problem is they just sit dormant just not growing. I grow under lights. Last year.. No problems this year no growth. Seeds r less than a year old. HELP.
Hi and thanks for your comment. To work out the problem, we need to eliminate a few possibilities. First, check that the temperature and humidity levels within your grow area are suitable for vegetative growth: ideally from 20 to 28ºC with 40-60% RH. Then verify whether your lamps need changing – old bulbs put out significantly less light than new ones, which could be leading to poor growth. If all those factors are as they should be then the most likely culprit is the soil mix itself – the quality can vary from season to season, even with the best brands, so it’s always possible that there could be pests or pathogens in the soil which are preventing the seedlings from making progress. I would recommend trying with a different brand of soil to see if that makes a difference. I hope that helps. Best wishes and good luck!
I germinated in paper towel until tap root was as long as seed it curled around the seed anyway my question is if I planted in jiffy pod should I put it under light or wait till it pops up to put it in the light .
Hi and thanks for your comment & question. The newly germinated seed doesn’t really need a light source while it’s below the soil surface but as soon as it pops out it will need light to prevent it from becoming stretchy, lanky and unhealthy. For this reason, it’s probably best to keep it under a light with a photoperiod of 18 hours light and 6 hours darkness for the day or two that it takes to break the surface. I hope that helps, best wishes!
You’re incorrect, seeds should be planted pointy end up crown down.
Hi Master, thanks for your comment. I honestly don’t believe there’s a correct or incorrect way. In our time, we’ve tried germinating seeds point down, point up and also laying them on their side in the soil, and we’ve come to the conclusion that it makes no difference at all – we certainly didn’t see any real difference in the results of one method compared to another. In nature, cannabis seed dispersal doesn’t rely on the seed landing in the soil in any particular position and it’s managed to spread pretty well! That said, if you like to sow your seeds pointy end down, then that’s great, keep doing it your way if it works for you! Best wishes!
I had my seeds in the paper towel for 3 days. The tap-roots appeared(not out just showing a bit) and I planted them in the soil. 3 days have past and I haven’t seen any progress. Is there a reason why this is happening?
Hi Sean, thanks for your comment. As long as the soil is neither too wet nor too dry, there shouldn’t be a problem with the seeds. They can take a few days to pop their heads up above the surface once they’re planted, the root needs to work its way downwards and find a solid hold to be able to push the seed head out of the soil. Speaking from personal experience, don’t be tempted to dig around looking for them as you’ll probably do more damage than good. The only times that seeds didn’t come up for me were the times I overwatered them, it’s crucial that they get enough air at this moment and too much water can lead to them rotting quickly. Of course, if they totally dry out then they’re not going to survive either. At this stage, I’d just recommend patience, good luck! Best wishes!
This article has a lot of nonsense in it. From Mandala Seeds: A #1 seed killer is a closed humidity dome/mini-greenhouse. Humidity domes are only required for rooting cuttings. Many growers make the mistake of thinking that they need a high ambient humidity for germination or seedlings. This is an unfortunate myth of cannabis cultivation. The high humidity and lack of fresh ventilation quickly causes fungus in the soil or growing medium and the seeds can rot! Cannabis is not an orchid or swamp plant! The seeds need a well aerated growing medium to germinate well. Seedlings also cannot tolerate high humidity and can easily be attacked by fungus such as fusarium and pythium. Only the soil or growing medium should be moist for optimal germination and seedling growth. Ambient humidity is best at or below 50%. Btw, seed should be planted with the pointed end UP, not down. Tap root ALWAYS goes up no matter how you place the seed. It’s by the nature, goes against the gravity to create a support for itself so it can push the seed out. It you put it with the pointed end down it will have to make double turn loosing the precious energy stored in the seed.
Hi, thanks for your contribution. Mandala Seeds give some helpful advice but they don’t have a monopoly on germination methods! In my 20 years germinating seeds I’ve tried all different methods and I’ve found good and bad in all of them. except for the methods using moist paper towels, I refuse to use it these days – I found that’s a great way to get mold problems and a really bad start to the plant’s life! That definitely is far too much humidity. as for ambient humidity, we don’t specify anything in this post. What we do say is that the medium in which the seeds are germinating should be at about 70% humidity for the best results. There’s nothing wrong with using a humidity dome or mini greenhouse, as long as you know when to start ventilating. of course if it’s kept sealed all the time then problems are bound to arise! These days I start all mine in a glass of water with a few drops of H202 and then once the seeds open (usually 24 hours) they get transferred to the substrate. As for the point down/point up debate, I think I’ll need to do a side-by-side comparison to settle this in my own mind. I’ve always planted them point downwards or on their side and I’ve yet to see any weird stuff like roots popping out of the surface, or doing a loop-the-loop before the seedling breaks the surface. But it’s clear that the debate needs to be settled so I’ll do an experiment and I’ll be happy to be proved wrong! EDIT: I’ve since germinated over 100 seeds as a test, 1/3 of them went in the soil with the point downwards, 1/3 sideways, and 1/3 with the point upwards. Most of the seedlings broke the surface at around the same time but it’s clear to see that the ones that I’m still waiting for are mostly those that went in with the point upwards. The next step has to be a test in a terrarium so I can actually see what’s going on but I’m almost ready to call complete BS on this “point upwards” theory, FWIW. Thanks again for your comment, all the best!
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