When To Harvest Marijuana Seeds?
After the whole process of germination, growth and flowering, a lot of growers ask themselves when to harvest Marijuana seeds. Usually, the breeders will include a suggested flowering time for each strain, but as a rule of thumb, Indica marijuana plants harvest in 6-8 weeks while Sativa Marijuana plants take 10-12 weeks.
Look for these signs for when to harvest Marijuana seeds
You can also judge the ripeness of the Marijuana by taking a look at the trichomes; or little hairs/crystals on the flowers and surrounding areas of the Marijuana plant. If they are transparent its still too soon, if they are milky white they are ready and if they turn brown they have become over-ripe. It is also advisable to follow the instructions to harvest Marijuana seeds on the packet since most reputable breeders also have a tried and tested flowering time for optimum ripeness, potency and flavour of a Marijuana strain.
If you meant when to harvest seeds from cross-pollinated Marijuana plants, then the seed will fall from the flower by itself once it is mature and ready to germinate into another Marijuana plant. Usually, as a best practice to harvest Marijuana seeds, some growers wait for the whole flowering cycle to end just as if they were harvesting the flower.
You might find our FAQ Submission How Do I Harvest My Plant? useful
Preserving Cannabis Genetics: How to Collect and Store Seeds and Pollen
Sometimes a grower has to move on from a certain strain. Maybe you’ve been growing the same strain for a long time and it no longer makes as much money as it used to, or maybe you just want to mix it up and start growing something else and don’t have the space for it.
It can be bittersweet saying goodbye to old genetics, but sometimes it’s unavoidable. You can take clones or keep a mother plant, but those aren’t ideal because they require a lot of care and maintenance, especially if they aren’t producing flower.
Fortunately, preserving genetics for long-term storage is easy and will save time, money, and space in the long run. Through seed and pollen collection, you can hang onto those genetics that you can’t fully get rid of and safely store them for future use.
The Benefits of Long-Term Storage
Cannabis genetics are often sourced from external companies and organizations such as nurseries and seed banks. For the individual grower, saving seeds and pollen removes this reliance on external companies. This is especially true with pollen, as very few (if any) companies offer pollen to the public.
Saving space is a big reason to consider long-term storage of seeds and pollen. Mother plants lay dormant in a vegetative state and take up lots of space. Maintaining this extra space is time-consuming and takes extra resources like water, soil, nutrients, light, and other costly elements, all for something that doesn’t produce flower. Even keeping clones of an old strain around will take up space and resources.
A grower or breeder can also freeze the progress of a breeding project for months or years without losing any of the long, hard work. Endeavors such as phenotype hunting and maintaining desired mothers for breeding and cloning can all be saved for later through genetic preservation. This process is like backing up work on a hard drive.
How to Collect Seeds
Cannabis is for the most part dioecious, meaning that the male and female reproductive organs exist on two separate plants (although hermaphroditic plants do occur). It is also a wind-pollinated plant, so pollen must be transferred from a male stamen to a female pistil via the air in order for pollination to occur and seeds to form.
A female cannabis plant that has received pollen from a male will produce many seeds over the course of its maturation cycle. Upon senescence, when the female plant is fully mature and ready for harvest, its seeds will be ready for stratification and collection.
To collect seeds, it’s important to wait until they are fully mature and ready for harvest. Cannabis with seeds takes longer to mature than cannabis that only produces flower.
To tell if a seed is mature, take a look at its shape and color. Premature seeds will be small and light in color, taking on a beige hue. Fully mature cannabis seeds are more full in shape and size and have a much darker brown hue, sometimes accented by black tiger stripes.
Deseeding cannabis can be done by hand or machine. This process typically takes place after the plant has been dried for one to two weeks after harvest. This way, seeds will have reached their maximum maturity and plant material will be brittle enough to break apart with minimal effort.
When collecting seed by hand, use a fine screen to help catch trichomes that will break off during the process. This material is valuable and it would be a shame to waste.
To release the seeds, simply break up the dried buds over a screen and they will fall out. You can release the seeds en masse by rubbing the flower between your fingers and lightly breaking it apart.
Separate or sift seeds over the screen to remove any unwanted plant matter from the seeds themselves. Brush off the seeds—they should be completely free of any remaining plant material such as leaves, stem, or trichomes, as these elements put seeds at a higher risk for contamination and spoilage during long-term storage.
Male cannabis plants will produce pollen several weeks into their flowering cycle. Once their pollen sacs have opened up and released, the plant will begin to senesce and eventually die. It is important to collect pollen right as the sacs are beginning to open up, as this is the time pollen is most viable.
The best way to harvest pollen for storage is to remove an entire male flower cluster and place it in a sealed storage container for several days. After the cluster has dried, place it over a micron screen with parchment or wax paper underneath, and give it a light shake. This will allow the pollen to separate from any remaining plant matter and fall through the screen and onto the wax paper.
Moisture is a death sentence for pollen viability. Because of this, many breeders opt to mix flour into their pollen at a ratio of 4:1 (flour to pollen) when storing it long-term. This additional step will help keep pollen dry for a longer period of time.
Seed and Pollen Storage
Long-term storage requirements for seeds and pollen are similar. Both require cool, dark, dry, and oxygen-deprived environments for optimal preservation.
When storing seeds, place them in an air-sealed container that doesn’t have any light leaks. Film canisters, medicine bottles (non-translucent), and any sealable storage jar will work fine. The idea is to reduce the amount of oxygen present in the storage space as much as possible. You can also add uncooked rice to the storage container, which acts as an absorbent, to reduce moisture content.
For a cool environment, store seeds in either the refrigerator or freezer. Seeds need a consistent temperature without fluctuation to remain dormant long-term.
As mentioned above, the best way to reduce moisture in pollen is to mix it with flour. For long-term storage, it can be kept in a sealed vial or freezer bag. You can keep it in the refrigerator or freezer, though for optimal long-term storage, the colder the better.
The Shelf Life of Seeds and Pollen
You can expect cannabis seeds that have been sealed and properly stored to last for several years, and in many cases, longer. Seeds may be dormant, but they are still alive. Over enough time, they will lose their viability.
It’s important to continually practice germination testing to be sure your stored seeds haven’t lost all viability. To test this, periodically plant a seed and document its ability to germinate.
Fresh seeds should have a germination rate close to a 100%, whereas older seeds will see a significant drop off over time in their ability to germinate.
Out in the open, pollen may be viable for one or two weeks under normal conditions. However, when frozen and sealed, it can last up to a year and even longer. Pollen is more unstable than seed and even under the most optimal conditions, it isn’t expected to have as long of a shelf life.
For both seeds and pollen that have been frozen long-term, it’s important to avoid defrosting until they are ready to be used. Fluctuations in temperature and moisture content will quickly destroy their viability, so maintain a steady temperature for as long as possible. Warming and freezing multiple times isn’t good.
When it comes time to use frozen seeds, remove them from their container and let them sit out on a dry surface for several hours. Letting the seeds reach room temperature will help ensure a successful germination.
Pollen should also be placed at room temperature before using. Since pollen can be much messier to handle, it’s best to carefully transfer a sample from its long-term storage container to a fresh container before using it to pollinate a plant. This way, you don’t have to use all of the pollen and saved pollen can go back in the freezer with minimal exposure to warm air.
The Importance of Collecting and Harvesting Cannabis Seeds
T here was a time in our not-too-recent history when a sack of weed almost always included seeds. However, as cannabis cultivation evolved, so did the demand for sensimilla, or high-quality, seedless cannabis. Breeders not only began developing their own customized strains, they also started specializing in the cultivation of very special cannabis seeds. These seeds are used in both the breeding process and the wide-spread distribution of the carefully created strain itself.
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The Role of Seeds in the Breeding Process
The process of breeding the perfect strain requires a controlled production of seeds. Breeders must force their favorite plants to produce pollen and then use it to pollinate other favorite strains, thus creating “cross-breeds” of their two selected parents. Note that this process is not haphazard like the seeds one might find in a poorly-controlled outside marijuana grow – cannabis seed cultivation is a precise process that requires controlled, sanitary environments that are thoroughly sealed to prevent outside dander from getting in.
The plants can “veg” here, or continue their vegetative growth phase if trying to increase their size before seed production begins, but it’s not necessary. Once the plants are large enough, they are put into a flowering light cycle of 12 hours light and 12 hours of complete darkness.
Within a few weeks, the male will produce pollen sacks which will soon burst and get carried off into the air to pollinate the females. The females will now produce seeds which may continue to be used in the breeding process or harvested and sold to the public.
For the purpose of seed production, only around 20 females are recommended per male. However, a single male can realistically pollinate hundreds of females, hence the importance of a tightly sealed environment during the seed production process.
Natural Cannabis Seed Production
Cannabis is an amazingly resilient plant and doesn’t require male pollination to produce seeds. Evolution has bestowed upon the cannabis plant an amazing ability to self-pollinate when there are no males around to do it for her. Whether stressed or old (for example, a female cannabis plant that is not harvested before her prime), if a female senses an environment that is not conducive to long-term growth, she will produce seeds in hopes that her legacy will continue.
This is how feminized cannabis seeds are produced. Breeders will carefully stress a healthy female plant to “trick” her into thinking her life or safety is in danger.
One common method is to stress the female by applying solutions like colloidal silver or silver nitrate generously onto the leaves when she first enters the flower light cycle. Within 3-4 weeks, male sex organs will appear on the nodes of the female plant. Please note, applying these stress-inducing solutions to plants renders them unsmokable. The particulate cannot be washed off thoroughly because it settles deep into the surface of the plant. This method is for seed production only.
Another method is to simply let a healthy female age. If she grows past maturation, she will produce male “banana” pollen sacks without any male chromosomes. Though she may look like a hermaphroditic plant at this point (one containing the chromosomes of both male and female), the pollen she produces will contain only XX chromosomes and therefore cannot pass the Y (male) chromosome down to its heirs. Pollen collected in this way is then used to pollinate another female which will then produce female-only seeds.
How to Collect Cannabis Seeds
Though many grow ops aim to do away with seeds to grow fine sensimilla instead, sometimes breeders want seeds. Whether to grow their own crops or to sell to a demanding public, cannabis seed cultivators have their goals set on producing healthy, happy seeds in lieu of big, beautiful buds.
Seed crops are harvested when the seeds are plump and dark, often with a tiger stripe appearance (around six to eight weeks into flowering).
After harvesting, the bud is dried and the seeds are collected. Small-scale seed collection is done by simply crumbling the cannabis flower and collecting the seeds that fall out (this video by Johnnys Green Extractions offers a clever way to separate seeds from flower using an old vinyl record cover).
Commercial seed collection usually involves special machines that crush dried flower then pass the trim and seeds into separate bins. After seeds are collected, they’re stored in opaque, air-tight containers to prevent them from rotting or sprouting prematurely.
Though cannabis flower is usually cultivated to be seedless, sometimes the seeds are the whole point. Breeders pay special attention to the pollination, harvest time, and drying process when growing cannabis specifically for the seeds to improve the likelihood of a successful harvest.
Frequently Asked Questions
How are Feminized Seeds Made?
Feminized seeds are made by inducing a female plant to produce seeds without being pollinated by a male. These resulting seeds will not contain a male Y chromosome, only retaining the two X chromosomes from the female plant, and thus all of the resulting seeds will be female. This process can be done by stressing the plant, altering it with chemicals, or allowing it to grow past its harvesting time.
How Many Plants Can a Male Cannabis Plant Pollinate?
For professional production, it is recommended to pollinate about 20 female plants per male plant, but this is done to ensure tight oversight and quality control. In the wild, a single male plant can pollinate hundreds of female cannabis plants.
Can You Smoke Cannabis That Has Been Treated with Colloidal Silver?
No, colloidal silver is only used on plants raised for seeding purposes, it makes the plants that it is sprayed on unsmokable.
How are Strains Crossbred?
Cannabis breeders create crossbreeds by using the pollen of one strain to pollenate seeds with another strain. The resulting seeds will have genetics from both parents. These new plants are selected by their desirable traits and then stabilized through further breeding, typically using the genetics of their parent strains.
Have you ever harvested cannabis seeds? Share your experiences in the comments below!
Abby is a writer and founder of Cannabis Content, a marketplace designed to connect cannabis writers and creatives with businesses in the industry. She has been a professional cannabis writer since 2014 and regularly contributes to publications such as PotGuide and M&F Talent. She is also the Content Director at Fortuna Hemp, America’s leading feminized hemp seed bank. Follow Abby on Facebook, Twitter, and Linkedin.