Whether you are a cannabis fan who has just begun growing a couple of plants recreationally, or you are looking to test your green thumb for the first time, there is one question that’s going to come up at some point. Do seeds go bad? Let's find out! Sprouting old marijuana seeds is difficult, but not impossible. Here’s how to do it and, in the process, save yourself some seed-buying money.
Do Cannabis Seeds Go Bad?
M any pot fans are starting to look into growing their own supply. After all, how hard can it be? Nature does it all the time, and it doesn’t even have any grow light options other than the sun. While you may not be producing showroom quality nugs, there’s a pride that comes with tending to your own garden and snipping buds straight off the branch. Plus, you can’t beat the price.
Plenty of online stores sell seeds so it’s pretty easy to pick your favorite strains to start. However, if it’s been a while since your seeds arrived and they’re not yet planted, you can forgive yourself for wondering if maybe you’ve waited too long. After all, how long do marijuana seeds last? Whether you are a cannabis fan who has just begun growing a couple of plants recreationally, or you are looking to test your green thumb for the first time, there is one question that’s going to come up at some point.
Do Marijuana Seeds Go Bad?
First off, marijuana seeds are the same as many other plant’s seeds. A waxy outer shell called the seed coat protects the embryonic shoot, stem, and root contained within, which are nourished by a nutrient-rich oil surrounding them. As long as the shell remains intact and the plant inside doesn’t dry out or get damaged, your seed can still grow into a cannabis plant.
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However, this shell will not last forever. Once it dries out and hardens the seed coat can crack and expose the embryonic plant to damage. Or the seed coat hardens to the point that it no longer lets in moisture. In both cases, the seed is no longer viable.
Of course, there is some debate in the cannabis community over how long do marijuana seeds last. Some growers claim that when stored in the ideal conditions, marijuana seeds can last anywhere from six months to a year after packing and still spout once placed in the soil. Other producers believe that marijuana seeds can last up to a decade if properly refrigerated in the right containers.
Most seed producers agree that on average three to six years is a maximum for viability, and every day that the seed is stored drops the chances of it germinating just a little bit.
So how long do marijuana seeds last? In general, six months is the maximum if you’re looking for a nearly 100% germination rate. After three years, you’re looking at a germination rate of around 50%.
What constitutes “ideal conditions” for cannabis seed storage also depends on the genetics of that particular plant. Some cannabis strains produce a much hardier, longer-lasting marijuana seed that can last for years and still stretch their leaves once planted. Others produce seeds that need to quickly return to the soil.
How Marijuana Seeds Are Stored
In terms of long term storage for your marijuana seeds, there are four main factors to consider:
When it comes to how long marijuana seeds last, temperature is the main factor. In nature, heat tells the seed that winter’s over and it’s time to start sprouting. If your marijuana seed’s not in the soil, this means that the plant matter inside the marijuana seed will begin to germinate and then rot.
41 degrees Fahrenheit (5 degrees Celsius) is the absolute warmest you want your storage spot to be, with the sweet spot being somewhere around 38 degrees Fahrenheit.
If you are refrigerating your marijuana seeds, they’ll last the longest in a separate unit or a spot near the back. Every time you open your fridge you are changing the temperature which can harm the seeds over time.
Humidity is also your enemy when it comes to how long your marijuana seeds will last. When a seed gets wet, it cracks open to allow the sprout and root out. This will let in rot if the seed isn’t planted. A humidity level of about 5% is the maximum you want to allow.
Much like heat and humidity, light tells that seed to wake up because it’s time to spring forth.
In order to keep your seeds from going bad, it’s best to keep them stored in a dark container in order to avoid light. photo credit
By keeping your seeds in a dark or opaque container, they’ll keep dozing long term. Light can also damage the surface of the marijuana seed, which in turn will damage what’s stored underneath, causing your marijuana seed to go bad.
Besides being dark, for your marijuana seeds to last long term, you want to expose them to as little oxygen and carbon dioxide as possible. These gasses are what growing plants breathe, as well as the pests that consume them. If you’re refrigerating or freezing your marijuana seeds, make sure your container is as airtight as possible. If you can vacuum seal them, even better.
Alternatively, if you’re planning on planting in the next few months, regular mailing envelopes will do in a pinch. They’ll keep the marijuana seeds out of the light and dry, so all you have to do is store them in a cool place. Plus, envelopes make it easy to label your strains so that you can keep them separate.
How To Tell If Your Marijuana Seeds Are Still Healthy?
What should you do if you find some old seeds and have no idea how long they were stored? Maybe past you put them in a freezer bag in the hopes of keeping your favorite strain alive, or found a couple at the bottom of a baggie that the trimmer missed.
How do you know if your marijuana seed has gone bad, or if it’s healthy and viable to grow into a plant? There are four easy ways to check if your marijuana seed is still good.
If your seeds are dark brown, black, or gray, that’s a very good sign. The shell is intact and uncompromised, which means the genetic material inside has been kept safe.
Seeds should have a dark color. If seeds are still green they are probably not ready yet. photo credit
Viable seeds should also have stripes or spots all the way around. If the seeds are white or green, they’re most likely still immature.
Check if the seed still has a waxy coating. A healthy seed should have a slight sheen to it, as though it’s been oiled. This means the seed still can retain moisture.
If the seed is still healthy, you should be able to lightly squeeze it without it crunching between your fingers. If the shell has no give and splits or splinters under light pressure, then your marijuana seed has gone bad and has no chance in the soil.
Cracks or Holes
If there are any cracks or holes anywhere on the shell, your marijuana seed’s likely gone bad and will most likely not sprout. Bacteria and other harmful lifeforms can find their way into the seed, or it will dry out.
The True Test of a Cannabis Seed
Of course, the best way to test whether your seeds will sprout is to plant them and see. If some green shoots climb their way out of the soil after a couple of days or weeks, you’ve got your answer.
Storing marijuana seeds is a great way to make sure you always have your favorite strains on hand, as well as to keep yourself stocked up on plants for the long haul. Luckily, marijuana seeds can last for years as long as you make sure your seeds are cool, dry, airtight, and out of sight. There’s no better time than now to learn a new skill, so let’s see how green your thumb can get.
How Do You Tell If a Seed is Good or Bad?
If the seed is dark with stripes or spots all the way around, has a waxy shell that doesn’t crack when you give it a light squeeze, and doesn’t have any visible cracks or holes, it’s probably still good. If there are holes in the shell, it’s dry, or especially pale, your marijuana seed’s probably gone bad.
Do Autoflower Seeds Go Bad?
All marijuana seeds can go bad, including autoflower seeds. However, by keeping your seeds at a stable 38 degrees Fahrenheit and at around 5% humidity, as well as airtight and out of the light, your seeds may last up to 5 years or more.
How do you like to store your seeds? Share your thoughts in the comments!
Paul Barach is a Seattle-based freelance writer, editor, and author with experience creating well-researched, edited web articles covering cannabis news, culture, history and science. Paul is a regular contributor to PotGuide and has also contributed to publications such as Medium.com, SlabMechanix, Litro, and The Trek. He prefers to spend his free time outdoors and most recently hiked the Pacific Crest Trail. So far he has only fallen into the La Brea Tarpits once. You can follow him on Instagram @BarachOutdoors and stay up to date professionally through his LinkedIn page.
The Good Germin’: How To Germinate Old Weed Seeds And Bring Them Back To Life
Before there were marijuana clones and mother plants, there were marijuana seeds, the foundation of the cannabis industry. And here’s some big news for you: The price of quality marijuana seeds is going up while availability is going down.
If you were waiting to buy seeds of the famous, scintillating heritage or landrace marijuana strains we’ve been featuring, now’s the time. I’ve been tracking seed prices of quality strains sold by reliable cannabis seed resellers, and I’ve found that in the past year, prices have gone up an average of 30 percent.
Now, let’s talk about the challenge of germinating old, stale, or otherwise defective marijuana seeds.
No matter if you get your marijuana seeds from seeded buds (sometimes called bag seed), from seed resellers, from friends, or from dispensaries, seeds from different strains can show substantial variation in size and minor variation in shape. What you should be concerned about are seeds that don’t look like the seeds in the main photo accompanying this article.
Properly bred, dark-colored and patterned marijuana seeds like the ones in the above photo are seeds that by far possess the highest germination rate and produce plants with the most vitality and performance.
But if your cannabis seeds are pale, green, gray, shrunken, split, dried out, misshapen, poorly marked, or possess a hazy sheen (kind of like old wax that dried on a car before it could be buffed out), then those are defective cannabis seeds. Take a look at the below photo, which shows defective cannabis seeds that are far less likely to germinate.
Green, split seeds and seeds that aren’t properly shaped (mature cannabis seeds should look like miniature footballs) are immature seeds that didn’t fully ripen before the buds they were forming in were harvested. These seeds are a waste of your time.
Seed defects develop if your seeds have been stored improperly, or if the seeds are more than 4–5 years old. Also, if you get cannabis seeds from the less-reputable resellers, you might receive old or otherwise defective seeds. I’ve seen growers who eagerly awaited their seed order, only to be disappointed when they tore into seed packs to discover easily identifiable duds.
In many cases, the disreputable seed seller won’t refund the order or send a replacement order, and the would-be grower is left with a mixture of acceptable-looking seeds and defective ones.
Seeds that are grayish and sheeny are old seeds, and likely desiccated. Old seeds sometimes split or crack. If seeds of any shape are pale, light brown, gray, split, or cracked, they’re defective. But you may be able to salvage some of them so they grow out into plants that yield buds.
Tried And Tested Methods For Getting Old Seeds To Germinate. But Do These Methods Work?
Growers offer many tactics for germinating old seeds, and I’ve tried all their suggestions. I want to emphasize from the outset, if cannabis seeds are grossly immature, they’re unlikely to ever germinate, and it’s not worth trying to. For that reason, the following germination suggestions are for seeds that were allowed to mature and ripen fully before they were harvested.
Method 1: One of the most generic suggestions for germinating old, stale seeds is to soak them in reverse osmosis water pH adjusted to 6.1 for 24–48 hours, before placing the seeds into a rockwool cube, rapid rooter, peat pot or other germination media.
Result: I’ve seen no benefit from this suggestion.
Method 2: This one is rather extreme and time consuming. It involves scraping off the outer layer of the seed, sometimes including the shell itself, exposing the embryo and cotyledon, which are usually white, gray-white or greenish-white.
You then place the unshelled seed material into your regular germination media. Obviously, this is a severe tactic, and you shouldn’t expect it to work. But if the alternative is to not germinate the seeds at all, it’s worth a try anyway. If it doesn’t work, you’ve lost nothing. If it works, you’re a winner.
Result: It worked for me about 15 percent of the time I tried it on old seeds.
Method 3: Another radical tactic is to manually split one side of the seed shell, narrowly exposing the embryo and other internal material that is usually protected by the hard outer shell. The split seed is immediately placed in the usual germination media.
Result: My success rate for this tactic has also been about 15 percent.
Method 4: Over the years, I’ve seen companies offer “old seed soak kits” that allegedly contain special materials that stimulate old seeds to germinate. I contacted those companies and asked for third-party test data and ingredients information so I could ascertain if its products have any validity. Strange that the customer service reps refuse to provide information beyond vague, meaningless verbiage such as, “Our product contains bio-catalysts.”
They also refused to provide product samples. I have to tell you, if a hydroponics manufacturer or seeds producer isn’t confident enough in their products to provide samples for testing, this is an indication that their products are no good.
Result: Grower friends of mine bought several brands of “old seed soak” products and found them to be no more efficacious than soaking old seeds in pH-balanced reverse osmosis water, or just putting unsoaked old seeds into germination media.
If “seed soaker” products contain anything useful at all, it would likely be gibberellic acid, which has been used to treat marijuana seeds to induce germination, vitality and female gender.
Method 5: I’ve done experiments with stale, old seeds using a gibberellic acid pre-soak (i.e., adding gibberellic acid to get the soak solution to 100–150 parts per million), pH adjusted to 6.1, versus reverse osmosis water at pH 6.1.
Result: I had a marginally better germination rate from the gibberellic-treated seeds.
There are other experiments you can conduct if you have old seeds and you want to see if there’s any hope for them. Experiment with using seedling heat mats at a slightly higher temperature than for fresh marijuana seeds. Another tactic is to place the seeds less deep in germination media than you normally would, at about 1/4 inch (normal depth is about 1/2 inch).
You can try placing a T5 high-output fluorescent lamp over them even before they germinate, as if the light can coax them back from the dead like Jesus did with Lazarus.
Of all these methods, one thing’s for sure: Always use proper germination techniques, materials and procedures, regardless of the condition of your marijuana seeds.
Old Colombian Gold: After Germination, More Challenges
If old, stale seeds germinate at all, it usually happens several days after fresh seeds germinate. Expect fresh seeds to sprout 1–5 days after you start trying to generate them. But I’ve seen old, stale seeds that germinated after 13 days.
Even if you manage to coax defective seeds to germinate, you still have some challenges. Here’s an example of what I mean…
I had rare seeds given to me back in 2011. They were allegedly pure Colombian Gold genetics sourced from a lid of partially seeded buds in the early 1980s. Proper storage for cannabis seeds is in an airtight container in the non-freezer part of a refrigerator, and that’s where these had been since they were sourced.
The person who gave me the seeds said the last time he’d grown them was 2003. He had a 50 percent germination rate, but the strain was too difficult to grow outdoors where he lived due to climate conditions and because his locale’s high latitude is the wrong growing condition for a tropical sativa like Colombian Gold. After that failure, he put the remaining seeds back in the refrigerator and forgot about them.
I didn’t expect much from those old seeds. They were so tiny, about the size of a pinhead, and were pale gray, with that sad, dull sheen that characterizes old or dead cannabis seeds.
Still, Colombian Gold is a valuable strain and I had an indoor grow room I could easily control to give that rare heritage strain the environment it needed in which to thrive. I soaked the seeds for 24 hours in reverse osmosis water to which I’d added a very tiny amount of the vitamin B booster B-52, which is useful whenever you have stressed plants or seeds.
I planted 17 seeds about 1/4-inch deep in rockwool cubes and kept the seedling heat mat at 80°F. After five days, I saw no germination. But at day seven, one seedling popped its head above the cube, and by day 11 I had five Colombian Gold seedlings.
Five seedlings aren’t enough for a grow op, so I started fresh seeds of other sativa strains. Those seeds germinated in three days or fewer.
I measured performance of the Colombian Gold seedlings against the seedlings grown from fresh seeds. Two of the Colombian Gold seedlings were mutants — their early set of true leaves failed to develop properly, and the next sets showed the same mutation, so I terminated them.
One thing to expect from stale, old seeds: They often show mutations. Also, expect weak growth and dullness. The three remaining Colombian Gold seedlings popped their heads above the rockwool, developed 2–4 sets of normal leaves, then stalled.
As the seedlings from other strains gained height every day and their leaves grew larger, the Colombian Gold seedlings went into suspended animation. I tried giving them varying doses of light intensity and wavelength. I kept them on the seedling heat mat. After three weeks, when seedlings from fresh seeds were nearing a foot or more in height, only one Colombian Gold seedling had grown taller, but it was still several inches behind the fresh-seed seedlings.
I ended up keeping only one Colombian Gold female. It never had the vigor, root development, bud development, stalk sturdiness or harvest weight that fresh seeds of the same strain would have yielded.
This poor little female clearly lacked vitality from its earliest days, and generally plants grown from old seeds often have to be babied along. This means giving them extra doses of vitamin B, less light intensity than the other plants in the garden, more staking and other structural supports, more carbohydrates (like Bud Candy and Microbial Munch), and more potassium silicate (like Rhino Skin) to strengthen their weak stalks.
These compromised plants lack vigor, and may take longer to mature and develop in both grow phase and bloom phase. They might have hermaphroditic tendencies, weak stalks, insufficient root development, or be especially prone to spider mites, gray mold, pythium root rot and other attackers.
I had to baby that Colombian Gold, but she rewarded me with authentic sativa buds that were long, thin, and a beautiful golden color. The high was stellar and very 1970s-ish.
If the plant had been stronger and more vital, I would have kept it as a mother plant or waited until I had suitable male pollen before breeding her. But she was an experiment, the seed she came from had lain dormant for too long, so her adult life was feeble. I was lucky to get any nice buds from her at all.
Mind you, old and stale seeds aren’t always a dead end. I’ve had nine-year-old marijuana seeds that sprouted within seven days and grew out to be lovely, strong, heavyweight marijuana plants. And those seeds had been stored in a plastic bag inside a sock in a drawer in someone’s bedroom!
The message here is that if you have defective seeds that are immature, don’t waste time on them. But if you have old seeds, there’s little harm in trying the tactics I’ve discussed to see if you can grow out any of them. You might be able to get rare genetic treasure from old marijuana seeds, which makes it worth the effort to try to germinate them.
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