Even though they don’t seem to do much, seeds are alive. They need to be handled with care and kept safe until you’re ready to grow them. If you’re not sure how to store cannabis seeds correctly, don’t worry, we’ve got you covered.
Seeds are pretty pricey, and there’s a lot more to storing weed safely than you might think. If you expose them to the elements and extreme temperatures, they’ll die.
Below we’ll discuss how long marijuana seeds last, the ideal storage methods, the role of environmental factors, and how to germinate cannabis seeds. Let’s get started!
How long do marijuana seeds last?
Seeds require proper protection from the elements to last. If carefully stored, you can extend their shelf-life.
Most cannabis seeds last up to six months at room temperature, but this timeline extends for users who keep the seeds refrigerated.
High-quality options can survive up to 10 years, but the duration varies according to environmental factors and the chosen strain. Hardy cultivars can withstand the test of time, while weaker varieties only last for three years.
Even the most expensive cultivars can’t survive in unfavorable conditions. Learn all about the various methods available before you start storing marijuana seeds.
How to store cannabis seeds
Seeds are living organisms. If you don’t take proper care of them, they can die. Using the right techniques for storing cannabis seeds means that you can preserve them for extended periods until you’re ready to plant them.
Before you decide on a suitable method, you need to ensure that the environmental conditions are ideal. Important considerations are:
- Humidity levels
- Temperature fluctuations
When any of the above factors aren’t correct, it can cause your seeds to germinate early or wilt.
If you’re wondering how to store cannabis seeds, light exposure is the first consideration. Seeds are unlikely to germinate when you store them in dark places. Storing your seeds near a window exposed to the sun’s rays can cause roots to sprout.
Too much light can also force the seeds to use their nutrients to survive before germination. This exposure causes the seeds to weaken, and they won’t develop once you plant them.
When it comes to humidity and storing cannabis seeds, you need to balance them carefully. If you have RH levels below 8%, your seeds become vulnerable to pests. Humidity levels above 10% can result in fungi developing and levels above 60% cause wilting and death.
The ideal range is 21–30% for short-term storage. Preserving seeds for longer periods means you need to keep them as dry as possible at 8–10%. Various levels have different consequences for the seeds.
|Below 8%||At these levels, any pests or insects around the seeds become active, reproducing and damaging them.|
|8–10%||The risk of pests still exists, but it’s the optimal relative humidity (RH) for long term storing of cannabis seeds.|
|12–14%||Fungi flourish in these conditions, which harms the seeds and affects their ability to germinate later.|
|18–20%||The seeds may sweat, and heating can cause them to rot.|
|20–30%||These levels are ideal for storing cannabis seeds for short-term use.|
|40–60%||When you increase the RH to 40–60%, seeds start germinating. These are also the optimal levels for cultivating most strains of cannabis.|
|80–100%||These levels are too high for storing marijuana seeds. Within 12 hours, they’ll start drowning, wilting, and dying.|
The best way to store marijuana seeds is in cool conditions, with 43°–47°F temperatures. The cooler it is, the less likely your seed will be to germinate. Many growers use a “no frost” refrigerator. The best place to keep them is in the fruit and vegetable section.
They need to be vacuum sealed beforehand. It’s safe to say that when you store cannabis seeds, the ideal environment is cold and dark with low humidity. Aside from refrigeration, some growers use a freezer or a dark spot at room temperature.
Any fluctuations in these conditions put your seeds at risk. You must keep your containers sealed until you plan to plant them. Opening them exposes the seeds to bacteria and pests.
Choosing containers: the best way to store marijuana seeds
If you want to know how to store cannabis seeds with minimal risks, you must choose the appropriate container. Different options are available depending on the duration of storage. Growers typically select between:
- Ziplock bags
- Mason jars
- Plastic containers
- Mylar bags
- Vacuum sealable containers
How to store cannabis seeds in the long term
If you’re wondering how to store cannabis seeds for more than six months, the most efficient option is a vacuum seal container. Ensure that it’s dark-colored and restricts access to light.
Place it at the back of your fridge or freezer. Once again, you need to ensure the appropriate RH levels. Use a desiccant to maintain the moisture levels and absorb ethylene. Popular options are silica gel packs or uncooked rice.
How to store cannabis seeds in the short term
Storing marijuana seeds in the short term is probably the easiest. You can select a drawer or cupboard that’s cool and dark. Ensure that the spot has a consistent temperature. Containers that work well need to be airtight.
Many growers use foam canisters, plastic containers, and mylar bags. The main factor is that they need to keep oxygen and water molecules out.
The best way to store cannabis seeds in the medium term is in an airtight container like a mason jar, ziplock bag, or vacuum sealable container.
You can use a refrigerator to extend the lifespan of your seeds. Be sure to check the humidity levels, as some refrigerators have low humidity levels.
Method for storing cannabis seeds
If you’re collecting seeds from the buds, you first need to dry them. After harvesting, place the buds in a humidor box for roughly 14 hours, then transfer them to brown bags for 2-3 days.
After that, place them back in the humidor box for another week, whereafter mature seeds should start falling off. This drying and curing procedure helps with the long-term preservation of seed quality. If you’ve purchased your seeds from a credible seed bank, you may skip this process.
The steps for how to store cannabis seeds are:
Step 1: Label your containers for easy identification later. It also minimizes light exposure.
Step 2: Insert a desiccant and place a layer of cotton wool as a boundary to separate it from the seeds. This step ensures that the moisture will be absorbed, and the seeds won’t be disturbed.
Step 3: Put the cannabis seeds on the other side of the cotton barrier and seal the container. Place it in the desired location until you’re ready to plant.
How long can you store cannabis seeds?
You can store cannabis seeds for anything from a few days to a few years. You need to control environmental factors carefully, and the better you are at providing optimal conditions, the longer they’ll last.
The containers you choose, temperature, and humidity levels all play a role in the total duration of safe marijuana seed storage.
How to germinate stored cannabis seeds
After storing cannabis seeds, you first need to establish they’re still healthy and viable. Ideally, they should be dark, round, and smooth. If they’re pale, white, and shriveled, you might not be able to get them to sprout.
A great way of testing them is by popping them into a glass of water. Seeds that sink are more likely to germinate. Ones that float might still grow a root, but the cannabis quality it produces will be poor.
You can try a few techniques for stubborn stored seeds that seem like they aren’t viable.
From the fridge
When you’re ready to cultivate your weed crops, remove the seeds from the fridge. This process is similar to the changes in nature when winter turns to spring. Place them in a glass with room temperature water for 12 hours.
To give them an extra boost, you can add one of the following solutions to the water:
- Fulvic acid
- Germination booster
- Hydrogen peroxide
- Gibberellic acid
Some seeds may germinate during this time. If not, you can still try one of the other germination methods.
If you’ve been storing your marijuana seeds for a long time, the outer shell may be quite hard—scarify the seed may be a good option to break the tough outside layer. Using sandpaper, gently scratch the seeds’ surface to allow moisture and warmth to enter it. You can do this before soaking.
Over time the ridge of each seed gets extremely tough. You can enhance the chances of germination by removing the ridge with a sharp knife or blade.
When you store cannabis seeds for a long time, there’s a chance they might not sprout roots. If all the other methods don’t work, you can use a blade to make a small cut in the shell. Ensure that you don’t damage the inside of the seed.
Short term storage germination
If you’ve only kept your weed seeds in storage for a couple of weeks, you can use the same methods as with newly purchased seeds. Common methods include:
- The paper towel method
- Ziplock bag technique
- Cotton wool germination
The paper towel method
This germination method is popular with marijuana cultivators. It’s affordable, easy, and uses mainly household items. It’s great for when you’re no longer storing cannabis seeds, as you can check for progress daily.
To use this method, you’ll require:
- Two paper towels
- Two dinner plates
- A bowl of water
- Cannabis seeds
The two dinner plates serve as a makeshift germination station.
1: Set out one of the plates as the base of the setup.
2: Wet the paper towels in the bowl of water and squeeze out any excess liquid so that they’re damp, not soaking.
3: Place one paper towel on the plate and space the seeds an inch apart on it.
4: Gently cover the seeds with the second paper towel.
5: Cover it with the plate.
Similar to the environment where you store cannabis seeds, you need to place your setup in a cool, dry place. Check on them daily, and add moisture if they seem to be drying out.
If the seeds don’t germinate within a week, they’re not viable. Check our germination guide for more info on this method.
The Ziplock bag technique
The Ziplock bag technique is quite similar to the previous method. The main difference is that instead of placing the paper towels between dinner plates, you slide them into a ziplock bag.
You store marijuana seeds at a lower humidity level than when you germinate them, and the increase encourages roots to sprout. Placing them in a Ziploc bag traps the moisture and provides the ideal environment for the seeds to flourish.
Germinating using this technique takes between 5-7 days. If there’s no sign of roots developing, discard the seeds.
Cotton wool germination
Growers have used cotton wool as a germination tool for many years. Some use it to start bean plants and other vegetables, but it works just as well for helping weed seeds get started.
This method works best if you’ve been storing the cannabis seeds for a few weeks and it requires:
- Two cotton pads
- A bowl of water
- Cannabis seeds
- A container with a lid
1: Soak the cotton pads in the bowl of water and squeeze out the extra liquid.
2: Smooth the cotton pad flat at the base of the container.
3: Place the seeds an inch apart on the cotton you’ve just inserted.
4: Cover with the second damp cotton pad and close the lid.
Place the setup in a cool, dry place and check on it every 24 hours. If the cotton appears dry, add moisture with a spray bottle. Seeds should germinate within seven days.
Locking up seed storage
Storing marijuana seeds is not as simple as it sounds. If you place them in a cupboard and forget about them for a few months, they’ll likely die.
You need to ensure that the temperature and humidity levels are correct and the space you choose needs to be dark. You also need to consider which container you’ll use carefully. Airtight options provide the best results.
Now that you know how to store cannabis seeds head over to the Homegrown Cannabis Co. store and browse through the wide range of options.
To keep learning about the importance of storing your cannabis seeds correctly, check our Potcast on the subject:
About the author: Parker Curtis
Parker Curtis has around a decade of cannabis-growing experience, specialising in soil-less and hydro grows. He’s mastering outdoor, greenhouse, and indoor grows.