There are two common methods to determine when a cannabis flower is ready for harvest: with the naked eye or with a magnifying glass or microscope. It's every marijuana cultivator's dream: to produce your own cannabis seeds and have a truly home-grown harvest for your next crop. Can’t fully get rid of that cannabis strain you grew for so long? Learn how to store seeds and pollen to clear space in your garden and hang onto those favorite genetics for another day.
I’m a first-time cannabis grower and my first plants are starting to flower, but I’m not sure exactly sure when I’m supposed to harvest them. How do I know my buds are ready? Also, is there anything I can do with the fan leaves after harvest, or do I just throw them out?
There are two common methods to determine when a cannabis flower is ready for harvest: with the naked eye or with a magnifying glass or microscope.
With the naked eye, the grower should closely watch his or her flowers until the pistils (little white hair protruding from the flowers) start turning red or brown.
As the cannabis flower reaches maturity, more of the pistils will become red or brown. A good rule of thumb is to harvest when just over 50 per cent of the pistils have become red or brown in color. The naked eye method is good for beginners who do not have access to a magnifying glass or microscope.
If possible, use a magnifying glass or microscope to determine the appropriate time to harvest your cannabis flowers. A magnifying glass or microscope allow a gardener to observe the trichomes (the small mushroom-like glands that contain most of the cannabinoids).
As the cannabis flowers start to ripen, the trichomes will turn from translucent to milky, and then, eventually, to an amber color.
For most hybrid plants, the peak THC percentages will be when the trichomes are mostly milky in color. In other words, most growers wait until most of the trichomes have become milky to harvest.
However, some growers like to harvest earlier (when trichomes have developed, but are still translucent) which produces a more energetic high for most users or later (when the majority of the trichomes have turned amber) which produces a more lethargic high for most users.
Having a magnifying glass or microscope allows the grower to determine when to harvest more accurately depending on his or her personal preferences. All in all, a magnifying glass or microscope is a valuable tool for harvesting and an investment worth making.
To answer the second part of your question regarding the fan leaves, you can make extracts from them. The large fan leaves contain cannabinoids, albeit at a far less concentration than the flowers.
Due to the low percentage of cannabinoids they contain, many growers dispose of the fan leaves. Personally, I like to make a coconut oil extract with my fan leaves. I do this by heating water and coconut oil in a large pot (I use one of my water bath canning pots).
The amount of water and coconut oil will vary depending on the amount of fan leaves you have. After the coconut oil has melted completely in the water, add the fan leaves, and cook over low heat for three to five hours.
You do not want to heavily boil the leaves; a light simmer is sufficient. After cooking, strain the water/coconut oil mixture through cheese cloth to remove the leaf material. The remaining mixture can be placed in the refrigerator for separation.
After 12 hours, the coconut oil will separate from the water and become hard. Discard the water and scrape the bottom of the hardened coconut oil to remove any sludge left by the plant material.
The resulting cannabis-infused coconut oil can be used for making capsules, baked goods, or as a topical ointment.
How to Harvest Your Own Cannabis Seeds
Congratulations! You’ve mastered the art of growing your own marijuana plants from seed and clone, and you’ve succeeded in bringing in a number of fruitful harvests. Perhaps you’ve even found a couple of strains along the way whose plants produce such a scrumptious bud that you have a new goal in mind: to produce your own cannabis seeds and have a truly home-grown harvest for your next crop
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Woah There, Tiger
As with most forms of sexual reproduction, in order to produce marijuana offspring (or cannabis seeds), you need a male and female plant. A male plant can produce pollen, which acts as a fertilizing agent in female plants, around two weeks before a female plant is ready to receive it. Because of this difference in sexual maturity, it is important to keep your male plant alive and thriving as you wait for your female plant to reach maturation. You can do this by pruning the male’s quick-growing buds and allowing the slower-growing flowers time to mature at a more leisurely pace.
When the Moment’s Right
Once the female plant has begun to produce flowers of a decent size with a number of long hair-like pistils, she is ready to receive the male plant’s pollen. There are two ways to approach the actual pollination stage: you can stick male and female together and let nature take its course, or you can manually pollinate specific female branches.
The first option is the easiest up front, but will ultimately take the most effort on the part of the grower. Essentially, when both male and female plants have reached maturation, you should place them next to each other and shake the male plant. This shaking will encourage a release of pollen, which will spread around the air and land throughout the female plant. Repeat this step once or twice a day for two days to ensure fertilization.
If the female plant is fertilized this way, there is no way to control how many cannabis seeds are produced, or where on the plant they come from. When it is time to harvest, you will notice that most, if not all, of your bud has a plethora of seeds buried within. In addition to being a lot of work, this mass production of seeds can be very wasteful. Growers may not have enough room to plant all of the seeds, and the leftover bud will be less robust due to the female plant’s energy being put into seed production.
Doing It by Hand
The second, more popular option is to pollinate specific branches on the female plant with pollen from the male. Before you get down to the dirty deed, you need to put in some prep time for both the male and female plants. First, turn off all fans and air circulation devices. For the female, prune the lower branches as well as the fan leaves that surround the branch or branches that you wish to pollinate. After preparing the female plant, clip off some of the more attractive and full-looking flowers from the male plant and place them in long paper wine bags (at least one good-sized flower per bag).
Now it’s time to pollinate. Carefully slide the paper bag with male flower around the prepared branch of the female plant. When the entire branch is covered, tightly close the end of the bag at the base of the branch using a zip-tie, string, or tape that will peel easily (such as masking tape or painter’s tape). Once the bag is secured, shake it strongly to encourage the spread of the pollen. Over the next couple of hours, repeat the shaking process one to two more times.
When removing the bag after pollination, be careful not to jostle the branch or the flower inside the bag. This could lead to accidental fertilization of other branches on your female plant (or surrounding plants). Although this requires more specific and detailed work up front, you will thank yourself later. This method of fertilization will provide you with enough seeds to plant for your next crop, while not overwhelming your female plant with seeds in every bud.
Bun’s in the Oven
Now you play the waiting game. Continue caring for and pruning your growing plants, and keep an eye on your female for the signs of fertilization. Once pollinated, most cannabis seeds will fully ripen within 4 to 6 weeks. You should expect to leave your fertilized flower on the plant longer than the bud that is not fertilized.
A ripened seed is structurally sound and dark brown or tan in color, often (but not always) with obvious stripes along the outside. The harvesting process is relatively simple. Simply dig into the fertilized flower and pull out the seeds. Don’t worry about messing up your bud harvest: female flowers that have been fertilized expend a lot more effort into growing seeds than producing THC, so the fertilized bud will not be nearly as potent to consume as the rest of the plant. (Of course, you can still use the seedless fertilized flower for shake, melting into butter, or making other edibles.)
The Circle of Life
Once you harvest your cannabis seeds, the next step is to plant them and start the entire process over again. If you’re not ready to start a new crop just yet, don’t worry. You can freeze the seeds and they will retain their ability to germinate.
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.