Cannabis Seed Macro Shot

How To Store Cannabis Seeds

Not having enough room to grow all of the seeds you have purchased or wanting to save favourite varieties for another season will leave you needing to store cannabis seeds. The incorrect storing of cannabis seeds can be costly to future yield and will reduce crop quality and quantity. That’s if they germinate at all.

How Long do Cannabis Seeds Last?

Successful storage relies on you being able to delay the process of germination and prevent any other damage to the seeds. Germination is the process by which the dormant seed is awoken and begins to use its stored nutrients to become a plant. To prevent germination the seeds must be kept cool and free from moisture and light. When stored properly cannabis seeds can be kept for two years without lengthening germination time or reducing plant quality. For longer storage, germination time will inevitably lengthen but if the storage is conducted correctly these seeds will produce virile plants. In some cases cannabis seeds have been stored and then grown after periods of ten years or more.

Autoflowering Seeds

The life of autoflower seeds can similarly be extended by reducing and controlling temperature, moisture and light. There are no different methods required to store these types of seeds.

3 Things to Consider

Preventing germination is key to the successful storage of cannabis seeds. Germination requires warmth, humidity and light. Exposure to any of these factors can trigger chemical changes within your seeds that will prevent their germination and growth later on:


Cannabis seeds that come into contact with moisture will combine it with stored nutrients to be used as a food source. This process even occurs when humidity is low and can diminish the nutrients available for germination. To combat this, seeds should be stored in an airtight container or kept in original airtight packaging. For best storage results, relative humidity levels should be below 9%. There are many specialist units available to reduce moisture. These include desiccants such as silica gel packs which can be a good, but a less accurate alternative.


Exposure to light may cause cannabis seeds to partially germinate. Without correct conditions for full germination this light exposure will result in damaged seeds and effect or prevent full germination. Using an opaque container or wrapping a glass container in black tape can prevent light from falling directly onto your cannabis seeds.


Temperatures approaching 24⁰C can trigger germination so it is essential to keep cannabis seeds cool for storage. The ideal temperature for seed storage is a constant 6⁰C. Changes in temperature can be nearly as damaging to cannabis seeds as higher temperatures. Refrigerators or specialist cooling units will keep your seeds at a constant temperature for best results.

How to Preserve Seeds for Long Term Storage

How to store cannabis seeds

For effective long term storage of cannabis seeds it’s essential that you begin the storage process as soon as possible. This will ensure that seeds are stored in the correct state and will not be altered by exposure to humidity, light or warmth. Store your cannabis seeds in a clean, opaque container and include a silica gel pack. This will reduce the humidity within the container to a safe level. Don’t be tempted to add several desiccant packets because this risks drying the seed out entirely and preventing later germination. The best containers are airtight and sealed firmly enough to keep out insects and other pests. Now store your container in an environment where you can maintain a constant low temperature.

Storing Seeds in the Refrigerator

Refrigerators are an excellent option for maintaining the constant temperature required to successfully store cannabis seeds. However, if they are regularly in use the opening and closing of the door could have an impact on temperature, humidity and light levels. To minimise this, place your container together with your seeds and silica gel towards the back of the fridge where there will be less disturbance. Or you could invest in a refrigerator specifically for seed storage. Frost free refrigerators will further decrease moisture but it is still essential to store your seeds in an airtight container first.

Storing Seeds in the Freezer

Storing cannabis seeds in a freezer will also provide you with the constant low temperatures required to prevent germination. However, each time you freeze and thaw your seeds the seeds will become slightly damaged. While it may be easier to keep your seeds undisturbed for longer in the freezer the colder conditions, over a prolonged period, will cause small amounts of damage. Any moisture left in the seeds when they are brought to below freezing will freeze and swell causing internal damage to the seed. If seeds are dried thoroughly and stored in a freezer professionally and slowly brought down to temperature the damage can be minimised. However, for most of us an airtight container in a refrigerator is the safest option.

What Types of Containers are Good for Storage?

Ball Wide Mouth Storage Jars

Having the correct container for your cannabis seeds is essential for successful short and long term storage. As well as being able to keep your seeds cool, dry and dark a good container must be secure from pests and prevent the growth of mould. Home vacuum sealers can be useful if you are storing seeds regularly or in large amounts. If you don’t want to invest in a vacuum sealer to store your cannabis seeds a glass jar with a glass lid can be a good option. You will need to cover it to protect your cannabis seeds from the light. The jar and lid will expand at similar rates maintaining an airtight seal at all times. For the ultimate in reliable storage you can purchase sealable curing vaults. These will allow you to set both the humidity and temperature.

At Growers House they sell a whole range of glass jars (including the Ball jar above), humidity packs and CVault storage. Click here to visit.

How to Store Your Cannabis Seeds:

  1. Store them in an airtight, opaque container with a desiccant packet.
  2. Keep the container at a constant low temperature in the back of a fridge.
  3. Protect your seeds from pests, moisture and light and temperature changes.
  4. For larger batches, vacuum pack your seeds and keep them in their own frost free refrigerator.