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Premature cannabis seeds

Tips & Tricks For Seed Germination

Looking for information regarding seed germination? Whether you’re a novice or an advanced cannabis grower, this is the guide for you. High Times Cultivation Editor Nico Escondido answers all of your grow questions in his weekly Nico’s Nuggets column.

The Question: What Can You Tell Me About Seed Germination?

I have a very technical question regarding seed germination, and I know you are just the man to ask. I have a friend who holds a PhD in plant physiology, and he once told me that plant seeds can be “turned on and turned off,” such that they germinate at a rate of 100 percent, or not at all.

For the life of me, I cannot remember how exactly he said to do this, and I have lost contact with him for the time being. I thought I might try my luck with you. Any info on this subject is appreciated! Thanks and keep up the good work my friend!

The Answer: Seed Germination Basics & Technical Theories

Thanks very much for writing in with your excellent question—and for your faith that we might be able to provide some insight! I think I have an idea of just what your friend was talking about when he described turning a seed “on and off” in terms of germination.

Seed Germination Basics

To start, we must first understand that not all cannabis seeds are viable for germination. Seed viability can be determined by the seed’s size, color, moisture content and age.

Young, immature seeds have very low rates of germination. These seeds are smaller and look very pale or white in color.

Bigger, plump seeds that are darker brown in color, with black tiger-like stripes are usually good bets for higher germination rates. Seeds that need to be stored long-term (more than six months) should be kept in the proper conditions—in an airtight container and in a dry, dark and cool place.

To germinate seeds, there are quite a few easy propagation methods.

Perhaps the simplest is to place the seeds between two moistened paper towels and lay them flat on a tray or plate. Keep the tray on top of a warm appliance or mild heat mat, regularly moistening the paper towels. After a few days, you will see the root tips begin to sprout.

If the seeds are being difficult, you can try floating the seeds in a glass of water for a day to help soften them up. Some advanced growers even use mild soap solutions, razor blades and plant hormones to increase germination rates on old or heirloom seeds.

Advanced Seed Germination

All of that being said, there are some more technical theories on plant seed germination that have been tested. And while some of these theories have been proven using specific seed varieties, it is not known if these techniques work on all plant species.

Perhaps the most well-known theory on turning seeds “on” and “off” for germination involves the flowering signal that triggers hormones in plants to fruit or flower. These same signals can also be used to trigger germination—or render seeds nonviable.

These “signals” are really the absorption of specific light frequencies.

In flowering plants, leaves of the plant pick up these frequencies, usually in a specific order and duration, which then triggers the release of hormones within the plant that alters the plant’s biological functions.

The Phytochrome Red (Pr) pigment in plant leaves that absorbs red light from the spectrum, in wavelengths between 660 – 760 nanometers (nm), is the first signal caller. The pigment called Phytochrome Far Red (Pfr), which absorbs red light at 760 – 800 nm, is the second signal caller.

Much in the same way that these leaf pigments trigger flowering, seeds—with just a single flash of light at these frequencies—can also be turned “on” and “off” for germination.

When red light at 660 – 760 nm hits a seed and then is immediately followed by a flash of red light at 760 – 800 nm hitting the same seed, the seeds will not germinate. Reverse this process, and the seeds will germinate at a very high rate, if not in totality.

Trials with cannabis seeds have indicated that this works for the cannabis plant species; however, in certain subspecies of cannabis (and strains containing diverse and hybridized genetics), the results were less than certain.

Still, many savvy breeders and seed producers have incorporated these techniques into their practices with good success. Conversely, it has long been suspected that Customs & Border Control agencies, as well as other law enforcement agencies, have also practiced these techniques on cannabis seed shipments across international borders, though that conspiracy theory seems a bit far fetched.

Premature seeds in my bud

Im wondering what problems i might be having with this Chemdawg from barneys farm (5 year old strain keep moms about a year before recycling them into new moms) recently noticed potency seems down and im seeing premature seeds through the bud and no hermi problems, wondering if my genetics could be diminishing or what could be causing this issue, thanks for the help.

Logan Burke
Well-Known Member

Could be a few things. I guess to start out, was your grow space totally light-proofed? Light leaks can cause a plant to turn hermaphrodite. I’ve also heard that environmental stress can cause this as well. Did you have any males for any period of time during that grow? Unstable genetics can give an increased chance of a plant turning hermaphrodite. I’m not sure if the seed’s age would or wouldn’t impact that. I’ve seeds about 5 years old though and thus far none have produced seeds. Is the Chemdawg by chance the autoflowering version?


Could be a few things. I guess to start out, was your grow space totally light-proofed? Light leaks can cause a plant to turn hermaphrodite. I’ve also heard that environmental stress can cause this as well. Did you have any males for any period of time during that grow? Unstable genetics can give an increased chance of a plant turning hermaphrodite. I’m not sure if the seed’s age would or wouldn’t impact that. I’ve seeds about 5 years old though and thus far none have produced seeds. Is the Chemdawg by chance the autoflowering version?

No it was a feminized seed pack grew them all out to select good phenos for a mom plant kept the mom alive through cloning new moms from the original and have done so for 5 years now, so now this mother plant has been recycled from a clone of itself 5 times now, not sprouting new seeds of chemdawg sorry if i was confusing with my question. I feel like the genetics may be degrading over time, i feel like it may be because of one of the cuts i took to be a mom was a bad cut, i don’t really know whats going on its potency hasnt been up to par and like i said i have premature undeveloped seeds inside throughout the bud recently in the last few grows of it, and no hermi problems like i said there are no hermies or male flowers at all, i havent had anything hermi or even spit a banana out what so ever, its not a hermi issue at least its not imo and i feel like maybe some type of stress with light could be an issue but its light tight in there, im wondering if maybe there are other enviro triggers or conditions that may make the plants more prone to seeding? Idk really stunted here and have tossed alot of ideas around with other growers and still drawing up a blank here

I have an indoor growroom and in my recent harvest I found seeds in the buds, but I’m sure there are no male plants in the room. I’ve heard that light leakage can cause plants to become hermaphrodites. Is this true, and if so, do you have any tips for avoiding this?

Cannabis plants are monecious. This means they have the ability to be either male or female. Or in the case of hermaphroditism, they can be both. The reason to make sure there are no males or hermaphrodites in your garden is because male flowers make pollen. When pollen touches the white hairs on a flower, it makes a seed, and seeded weed gives you headaches. Even though there are reasons in nature hermaphroditism could be important, such as continuing the species in case there is no male present, hermaphroditism is generally a bad thing when talking about cannabis plants.

Light poisoning is the most common cause for a normal plant to hermaphrodite.

Light poisoning refers to the flowering night cycle of a plant being unnaturally interrupted with light. The best way to prevent this is to close yourself inside your darkened room during the daylight, and then after allowing a few minutes for your eyes to adjust to the dark, check for any light leaks from covered windows, door jams, etc. Also cover all timer and appliance lights with tape.

Negative stressors can combine with small interruptions of the light cycle to cause hermaphroditism, especially with less-stable, clone-only hybridized strains. When the night cycle is abnormally interrupted, it sends a mixed hormonal signal to the plant. This can cause a full female plant to throw some male flowers. Male flowers are easy to identify, especially when side by side with female flowers. Male flowers look like small bunches of bananas, which will take a week or two to swell before they burst and release their pollen.

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Finding a hermaphrodite in your growroom can happen at any stage of the flowering cycle and is indicated by the presence of male flowers growing on the same plant as female flowers. As with all species in nature this can occur in varying degrees. A plant can become slightly or majorly hermaphroditic. In cases where singular male flowers are found between the branch and stalk nodes, you should be diligently removing them as they grow. You must re-inspect the plant top to bottom every few days to be sure pollination and seeding doesn’t occur. If you find male flowers (anthers) actually growing from within the female flowers (buds) the situation is a little more dire. You can still remove all the male anatomy as it appears, but it will be harder to find and much more prevalent. This is a horrible discovery that leads to a tough decision: Should you let the plant live and risk the whole crop being ruined by seeds?

In either case, once hermaphroditism has compromised the safety and purity of your sensimilla, the plant should not be propagated further. Remember, once a hermy, always a hermy. The plant pictured here is in the tenth and what should have been the final week of ripening, but a timer failed and one light stayed on continuously for almost two weeks, causing this vegetative regrowth. Because the light was continuous, the plant made no pollen. This method of re-vegging can be used to save a flowering plant you have no copies of, but be careful, as this may cause some strains to hermaphrodite.

Purposefully causing a plant to hermaphrodite is called selfing. Gibberellic acid or colloidal silver is typically sprayed onto the female plant. This technique is used to make feminized seeds and uses the plant’s ability to be both male and female to force a female plant to produce male flowers. The pollen contained in these male flowers can only produce female seeds. Just keep in mind that feminized plants should not be used for breeding, as they were produced without a true male, making them genetically inferior.