If you don’t begin with great seeds, you can forget about producing a harvest of high-quality marijuana. A lot of growers seem to forget one simple fact: Your seeds are alive! Although cannabis seeds are fairly durable, improper storage can ruin them. If you’re paying $10-$20 a seed, losing a full batch is an expensive mistake.
Before your marijuana seeds germinate, they are in a similar state to animals when they hibernate. Like all living organisms, your seeds can die if you don’t take care of them correctly. The good news is that cannabis seeds can last for five years after harvest with proper storage.
In this guide, we outline how to store and preserve your cannabis seeds. We focus on the following:
- Insects & Pests
- Germinating old seeds
Keeping Light Away from Your Marijuana Seeds
You must keep your seeds in a location that is cool, dark, and dry. It is best if you keep the seeds in their original packaging. When they are exposed to temperature changes or light, cannabis seeds begin using their store of nutrients. This is a disaster because they ultimately won’t have the nutrients to germinate.
When they are exposed to temperature changes or light, cannabis seeds begin using their store of nutrients.
Make sure your seeds remain away from light, as it can directly trigger germination.
What’s the Right Storage Temperature?
The best temperature to store your cannabis seeds at is between 43- and 47-degrees Fahrenheit. The lower the temperature, the less likely your seed is to germinate unexpectedly. Experienced growers tend to have special refrigerators to store their seeds. Ideally, your fridge is a no-frost model. If you can place the seeds in the fruit and vegetable section, that is even better.
Another option is to freeze the cannabis seeds. If you go down this route, please ensure that you vacuum pack them first. Then put them in a dark container. Also, it would help if you germinated these seeds immediately once they come out of the freezer. Don’t allow them to thaw first.
What About Humidity?
Here is a quick overview of what will likely happen to cannabis seeds at different humidity levels:
- <8%: The seeds will attract insects and other pests.
- 9 – 20%: Your seeds are more likely to develop fungi inside and out. They begin sweating at below 20% humidity. However, 8-10% is a ‘sweet spot’ for long-term storage in the right conditions.
- 21 – 30%: The ideal humidity level for cannabis seed storage.
- 31 – 60%: This is the germination zone, particularly once the humidity level goes past 40%.
- 61%+: You are endangering your seeds the higher the humidity level goes. Once it reaches 80%, your seeds will wilt and die in approximately 12 hours.
Your cannabis seeds need a certain level of moisture for germination. If the humidity level gets too high, your seeds will rot in storage. An extremely low level of humidity of around 8-10% is suitable only for long-term storage. If it drops below 8%, you offer any insects present in the seeds the chance to become active and start reproducing.
The Right Storage Options for Your Cannabis Seeds
You now understand that you must store the seeds away from direct light. We have also outlined the need for relatively low humidity and a refrigerator-level temperature. Different options are available depending on how long you intend to store the seeds.
If you only require short-term storage, a dark drawer or cupboard is sufficient. The most important thing, regardless of the duration of storage, is to avoid temperature and humidity fluctuations. Rapid variations in temperature, in particular, can destroy your seeds. If you live in a location with warm daytime temperatures and cold nights, avoid outside storage.
For short-term storage, place the seeds in a container with desiccant. Seal it, and place it in a cool, dark place.
Once you enter medium-term storage (a few months), it is time to use an airtight container. Examples include a mason jar or Ziploc bag. Place this sealed container in the fridge. Remember that opening your fridge can cause significant temperature fluctuations. As a result, it is ideal if you have a second fridge that is seldom used.
Also, you should note that modern fridges have low humidity levels. If the humidity is too low, your seeds will begin using up nutrients.
If you want to store your seeds for at least six months, use a vacuum-sealed container. You can achieve this effect by removing all the air from a Ziploc bag. There are also special vacuum-sealed containers available online. Put the sealed bag in a dark container and put it in the fridge.
You also have the option of placing the seeds in the freezer. Remember, though; you need to germinate them immediately upon removal.
A Note on Insects & Pests
Imagine paying $100+ for seeds, going to the trouble of storing them, only to find that insects ruin them. Unfortunately, all you need is one insect in a container to destroy all of your seeds. The first consideration is to avoid exposure to ultra-low humidity. However, for long-term storage, this is precisely what you are supposed to do!
One option is to spread diatomaceous earth (D.E) where you store them. This is a type of sand that has a fossilized algae base. Crucially, for our purposes, it serves as an excellent natural insecticide. Unfortunately, you shouldn’t use D.E if you plan to store your seeds in a fridge with other food.
Imagine paying $100+ for seeds, going to the trouble of storing them, only to find that insects ruin them.
It would help if you also stored your seeds as high above the ground as possible. This reduces the possibility of a pest like a rodent coming in and feasting on the seeds.
Insects and pests also thrive in dirty storage areas. As a result, you must ensure the storage area remains clean. Otherwise, you won’t just attract pests to your seeds; microbes will form and damage the seeds. Do you want to consume marijuana from contaminated seeds?
You can ‘test’ your seeds once you have removed them from storage. Place them in water. If they sink, they should be fine. However, if they float, it is more likely that they are bad seeds. You can still try to germinate, but there is a greater risk of producing poor-quality cannabis, or else the seeds fail to sprout. You can keep floaters in water for approximately 72 hours to see if they sprout a tail.
If you have old seeds not stored in ideal conditions, there are still a few ways to germinate them.
- Remove the hard ridge with a sharp knife.
- Soak the seeds in carbonated water with germination booster, fulvic acid, or hydrogen peroxide. Use room temperature water, and perform this pre-soak for at least 12 hours in a dark area.
- Scratch the tough outer shell with sandpaper. Believe it or not, this process could help warmth and moisture get inside. This process is called ‘scarring’ and should happen before you soak the seeds.
- Make a small cut into the shell as a last-ditch attempt to get it to sprout.
Final Thoughts on Storing and Preserving Cannabis Seeds
If you purchase marijuana seeds and intend to use them almost immediately, you should have no issues. Even so, it is probably best to keep them away from direct light. In the short-term, a dark cupboard is sufficient as long as the temperature and humidity are reasonable.
Once the goal is to store cannabis seeds for months rather than days or weeks, everything changes. You need an airtight container, which you should store in a fridge. Include a vacuum-sealed container if you plan to store the seeds for several months or longer.
When storing cannabis seeds, you must ensure they are not exposed to germination conditions. This means keeping them away from direct light. Also, store in 20-30% humidity (8-10% for long-term storage) and a cool temperature. Keep the environment clean to avoid pests, and consider the tips above for germinating old seeds.