How to germinate cannabis seeds

Germinating cannabis seeds is simpler than it looks: all it takes is damp paper, a closed container and a few days of patience. Yet this is the stage where most seeds are lost — and nearly always for the same reason. Below is the method we recommend at Pyramid Seeds, broken down step by step, along with the three places people go wrong most often.

If you are just starting out, it is worth browsing our marijuana seeds for beginners as well — hardy strains forgive a first-time grower a great deal.

What you will need

Nothing special to buy. All of it is already in most kitchens:

• Distilled water at room temperature. Not from the tap, and not from the fridge.
• A napkin or paper kitchen towel. Plain, with no fragrance or added coatings.
• A container with a lid — a Tupperware box or anything that closes properly.
• A spray bottle — for adjusting the moisture without drenching the paper.
• Pots of substrate — needed at the last step, but far better prepared in advance.

The water deserves a word of its own, because it is the thing people grab without thinking. Distilled water matters because tap water carries chlorine and hardness salts, and their concentration varies from one town to the next — you simply don't know what the seed is getting. Room temperature matters for the same reason steadiness matters later on: cold water straight from the tap is a temperature shock in the very first minute.

The germination method we recommend, step by step

Step 1. Prepare the base

Moisten a napkin or paper kitchen towel with room-temperature distilled water and lay it on the bottom of the container. The water should soak through the paper without pooling underneath it.

Step 2. Lay out the seeds and cover them

Place the seeds on the damp base without pressing them in or burying them. Leave a little space between them, so that later you can lift each one out without disturbing its neighbours. Cover them with a second damp layer and close the lid.

Petri dishes work just as well as a container — they are what you can see in our photographs. The principle is the same: a layer of damp paper, the seeds, a second layer, a closed lid. Their advantage is that a clear base lets you spot the roots without taking anything apart. If you are germinating more than one strain at once, keep them in separate dishes and label them: germinated seeds are very easy to mix up and impossible to tell apart afterwards.

The seeds do not need soaking, and must not be left sitting in water — neither before you lay them out nor after. We will come to exactly why further down.

Step 3. Keep it dark and at a steady temperature

Put the closed container somewhere dark where the temperature holds steady. The exact figure matters less here than the steadiness: a cannabis seed copes badly with sharp swings, rather than with cool or warmth as such.

That rules out the windowsill, the radiator and the space beside the hob — those are where the temperature moves most over a day. A closed cupboard or a desk drawer works far better.

Step 4. Air it out once a day

Open the container once a day for a couple of minutes. This does two things at once: it lets fresh air in and lets you see whether any roots have appeared.

While it is open, check the paper. If it has dried out, mist it lightly with the spray bottle. Lightly is the operative word — the aim is to bring the base back to damp, not to top it up for later.

A germinated seed is unmistakable: the shell splits along its seam and a white root pushes out. Until that happens, it is best not to touch or turn the seeds — look at them by lifting the top layer of paper, then put it back. Every unnecessary handling is a chance to interrupt a process that has already begun.

Step 5. Move them into substrate

As soon as a seed has germinated, move it into a pot of substrate. From laying the seeds out to a visible root usually takes between 1 and 7 days — the spread is normal and depends on the strain and the batch.

Pick the seed up carefully, by its shell rather than by the root, which is extremely fragile at this point. And don't put the move off: the longer the root gets, the easier it is to damage in transit. Once it has germinated, plant it.

Which leads to a practical point: the pots of substrate should already be standing ready. Seeds from one batch do not open at the same time, and if the first one germinates on day two while you have not yet bought substrate, you are choosing between rushing and losing a root. Far simpler to get everything ready on the day you lay the seeds out, then move them one at a time as each is ready.

Why cannabis seeds should not be soaked

This is where our method parts company with most of what you will read online — and it is the single biggest cause of failure among first-time growers.

To germinate, a seed needs two things: moisture and access to air. In nature a seed lies in damp ground, but it is not submerged. That combination is exactly what damp paper reproduces: the water is there, and so is the oxygen.

Leave a seed in water, or on paper that is too wet, and the oxygen runs short. In those conditions seeds do not germinate — they begin to rot. And it often looks harmless from the outside: you simply wait, day after day, and no root appears.

The most common version of this is the glass of water, which plenty of guides still recommend. Notice that even those guides come with a time limit attached, usually somewhere around a day. That limit exists precisely because of the oxygen problem — soaking is a race against the clock, and if you forget the glass overnight, the seed may not recover. The damp paper towel method has no timer to get wrong.

The reasoning behind soaking is easy to follow: it feels as though more water should soften the shell faster and get things moving sooner. In practice the shell softens on damp paper anyway, while there is nowhere for air to come from inside a glass. Soaking doesn't speed germination up. It trades one variable, moisture, for two problems at once.

How to tell a good seed from a bad one

Some failures get blamed on the method when the seeds were the problem all along: an immature or over-dried seed will not germinate even in ideal conditions. You can judge one by eye and by feel.

Colour and pattern. A ripe cannabis seed runs from light brown to almost black, often with a marbled or tiger-stripe pattern. Pale green, whitish and uniformly light seeds have usually been harvested unripe: they never built up their store of nutrients.

Firmness of the shell. Squeeze the seed gently between thumb and forefinger. A ripe one feels solid and does not give. If it dents or crumbles, there is nothing inside.

An intact shell. There should be no cracks, chips or dents, and a faint waxy sheen. A matte, dried-out looking surface usually points to long or careless storage.

Shape. A good seed is symmetrical and teardrop-shaped, with a clear seam running down it and a visible ridge at the base. Flattened or lopsided specimens come up less reliably.

Size on its own means nothing. It depends on the strain: some produce large seeds, others small ones, and it has no bearing on whether they germinate. Comparing seeds only makes sense within a single pack, not between strains.

Dark spots and film. Individual markings on the shell are part of the natural pattern and nothing to worry about. A greyish or white fuzzy film, a musty smell, or seeds stuck to one another are a different matter — they mean the pack has been damp. Those are not worth germinating.

Judge the pack, not the seed. Any pack will contain a few that are smaller or paler than the rest, and that is normal. The warning sign is when the pale, soft or cracked ones outnumber the good ones. A single unimpressive seed tells you nothing about the batch.

The float test doesn't work. The popular advice — drop them in a glass, the ones that sink are good and the ones that float are empty — is best left alone. It is the very soaking we advise against: for as long as the test runs, the seed sits without oxygen. A doubtful test for a real risk.

One last thing: what matters is not only how a seed looks, but how it was kept before planting. A pack that looks fresh but spent six months somewhere warm and bright will do worse than an unremarkable-looking seed out of the fridge. There is more on this in our guide to seed storage. And if you are still deciding what to buy, it is worth reading how the types of cannabis seeds differ — feminised, autoflowering and regular behave differently from the very start.

What happens next: from seedling to outdoors

After the move into substrate, the plant spends a while in its pot. The marker for the next step is simple: once it has three tiers of leaves, it can go outdoors.

There is no reason to rush before that. A young seedling with one or two pairs of leaves is not ready for wind, sun and the swings of open ground — and there is no bringing it back once it is out there.

Three tiers is not an arbitrary figure. It is a visible sign that the plant has stopped living off the reserves in the seed and is supporting itself. The marker is also convenient for not being tied to the calendar: some strains reach that point faster than others, but counting tiers is equally easy either way.

Common mistakes

What to grow first

For a first grow it makes sense to pick a strain that forgives mistakes in care. The photographs in this article show two of them: Tutankhamon, feminised and predictable as it develops, and Auto Galaxy, an autoflowering strain that spares you any fuss over light cycles.

The germination method is the same for both: moisture and air, exactly as in nature.

Frequently asked questions

How do you germinate cannabis seeds?

Place the seeds on a napkin or paper kitchen towel moistened with room-temperature distilled water, cover them with a second damp layer and close the container. Keep it somewhere dark at a steady temperature, and open it once a day for a couple of minutes to let air in and check on them. As soon as a white root appears, move the seed into substrate.

How long do cannabis seeds take to germinate?

Usually between 1 and 7 days. That spread is normal — it depends on the strain and the batch, so seeds from one pack will not all open at the same time.

How long should you soak cannabis seeds before germinating?

We don't recommend soaking them at all. Even the guides that suggest it agree there is a ceiling — leave a seed in water much beyond a day and it starts to suffocate. That ceiling exists because a seed needs two things to germinate: moisture and access to air. Water gives it the first and takes away the second, so soaking is a race against the clock. The damp paper towel method gives it both from the start, and there is no timer to get wrong. The paper should be damp, never soaking, and the seed should never sit in water.

Can you germinate cannabis seeds in a cup of water?

You can, and plenty of guides suggest it, but it is the method we advise against. A seed sitting in a cup has moisture and no air, so the clock starts running the moment it goes in — and if you forget it overnight, it may not recover. The paper towel method removes that risk entirely. It is also why we don't suggest the float test: checking whether a seed sinks means putting it in water, which is the thing we are trying to avoid.

What do good quality cannabis seeds look like?

A mature seed ranges from light brown to almost black, often with a marbled pattern, and has an intact shell with a faint sheen and no cracks. It feels firm and does not give under light pressure. Pale green, whitish or soft seeds were harvested before they ripened. Size on its own says nothing about quality — it varies by strain. Judge a pack as a whole rather than a single seed: a few smaller or paler ones are normal.

My seed hasn't germinated after 7 days. Is it dead?

Not necessarily, but 7 days is the outer edge of the normal range, so it is worth checking the conditions rather than the seed. The usual culprits are paper that has dried out unnoticed, a spot where the temperature swings through the day, or a container that has been opened and rearranged too often. Keep the paper damp rather than wet, leave it somewhere with a steady temperature, open it once a day and otherwise leave the seed alone.

What do I do once a seed has opened?

Move it into a pot of substrate, holding the seed by its shell rather than by the root. Don't wait for a longer root — the longer it gets, the easier it is to damage. Once the plant has three tiers of leaves, it can go outdoors.