How Long Do Cannabis Seeds Last?

The most important part of growing marijuana is the seed. If you start with a bad seed, you’re going to get bad (or no) results.

Assuming you buy some high quality seeds from trusted vendors, you can be pretty sure that the seed will germinate when you’re ready to grow.

But if you’re only growing 1 plant at a time, you’ll need to store the rest of your seeds.

Hemp oil n a glass jar and hemp seeds

In this article I’ll cover how you should be storing your seeds to maximize their life span and I’ll answer the question of how long seeds can last in storage, because it depends on several factors.

Average Lifespan of Marijuana Seeds

If properly stored in optimal conditions, cannabis seeds can last up to 5 years.

But take this answer with some caution….because there isn’t really a 1 size fits all answer here.

The truth is that every single seed has a different life span. In a batch of 10 seeds you’ll get 1-2 that will last 6 months, 5-6 that will last several years, and 1-2 that can last 5 years or more.

Every seed has slightly different conditions on the inside which determine how long they can last before they need to germinate or die.

The 3 Factors that Affect Seed Life Span

Before I go into the 3 factors that will determine how long your seeds will last, it’s important to touch on how a seed actually germinates.

The easiest way to germinate a seedling is to submerge it in warm water or fold it between wet paper towels and leave it in a warm place.

Notice something in common there?

A humid and warm place.

These 2 things promote germination.

So if you want your seeds to last a long time, we want to do the opposite.

We want to keep the seeds dry, cold, and away from light.

Close view of hemp seeds, macro photo

Humidity

Humidity is really just a fancy way of describing how much water there is in a given space.

Seeds for all plants, including cannabis, need water to stay alive and germinating as a seedling is the first step.

But if you want to preserve your seeds, then humidity is your enemy.

This handy chart from Royal Queen Seeds shows what happens at different levels of humidity.

Based on this chart, you can see that for long term storage you want to stay below 8% humidity and the lower, the better.

Humidity LevelImpact on Cannabis Seed
<8%Allows long term storage, up to 5 years.
8-9%Can attract pests
12-14%Can allow fungus to grow
18-20%Causes nutrient loss/breakdown inside of seed
20-30%Ok for short term storage
40-60%Seeds begin to germinate
80-100%Seeds can drown after 12-24 hours

Temperature

Remember earlier where I said that seeds require high humidity and warm temperatures to germinate?

Well for long term storage we want to do the opposite.

So keep your seeds in a cool place with low humidity.

Some people prefer to store their seeds in the refrigerator. I’ve never gone to this extreme but if you are positive you’ll be storing seeds for several years, this can make sense.

Just make sure you keep them in a dark container so they aren’t exposed to any light.

Light

Light is not a requirement for germination, but it will create a more rapid breakdown of the seed and cause issues if you plan to store the seeds long term.

Keep your seeds away from light to avoid issues, either by wrapping them in a dark material or storing them in a part of your refrigerator that doesn’t have lights.

Heap of hempseeds with cannabis plant on wooden background

Final Thoughts

Remember, storing seeds long term is not an all or nothing proposition. You can find seeds that last 10+ years and some that are dead on arrival.

But in general, the longer you store your seeds, the more likely you are to have issues when you try to germinate them.

Keep seeds stored in dark, cool places with low humidity and they should stay good for several years.

Yo, my name is Chad. I grow dope weed (haha) and want to help you do it too. I started growing a few years ago when it was legalized in my state and now I can help you avoid all of the mistakes I made!