How Long to Soak Marijuana Seeds Before Germination?

Germination is the first and most crucial step in growing cannabis. And while there are several techniques to initiate this process, soaking marijuana seeds in water is one of the most widely used and effective methods—especially for beginners.

But how long should cannabis seeds stay in water? Can you soak them for too long? What happens if they float or sink? In this article, we’ll cover everything you need to know about soaking cannabis seeds to ensure healthy and vigorous germination.

Why soak marijuana seeds?

Soaking seeds helps to simulate the natural conditions cannabis experiences in nature: a warm, moist environment after a rainfall. This triggers the seed’s internal mechanisms and tells it that it’s time to wake up and start growing.

Main benefits of soaking:

Hydrates the seed coat: Softens the shell so the taproot can break through more easily.
Speeds up germination: Prepares the seed to sprout faster than dry-sown seeds.
Identifies viable seeds: Seeds that sink are usually viable; floaters may be old or damaged.
Improves success rate: Especially helpful for older seeds or those with a hard shell.

How long should you soak marijuana seeds?

Recommended soaking time: 12 to 24 hours

Soaking cannabis seeds for 12 to 24 hours is ideal for activating the embryo inside without suffocating it. In most cases, this window is enough to fully hydrate the shell and start the germination process.

Maximum soaking time: 32 hours (with caution)

You should never exceed 32 hours of soaking. Seeds need oxygen to stay alive, and prolonged exposure to water can drown them. If a seed hasn’t cracked open after 24 hours, it’s safer to move it to a moist paper towel setup to continue the process.

What happens during soaking?

When you soak marijuana seeds, three key things happen:

Water penetrates the outer shell, reactivating the seed’s metabolism.
Enzymes inside the seed wake up and begin converting stored nutrients into energy.
The seed coat softens, allowing the taproot (radicle) to emerge.

Usually, the seed will crack and show signs of sprouting within 12 to 36 hours total (including both soaking and paper towel phases).

Step-by-Step: How to soak marijuana seeds

1. Prepare the Water

Use distilled water, reverse osmosis water, or tap water that has been left out for 12 hours (to let chlorine evaporate).
The water should be at room temperature, around 20–25°C.
Optionally, add 1–2 drops of hydrogen peroxide to the glass to help disinfect and soften the seed shell (especially useful for older seeds).

2. Place the seeds in a glass

Use a clean glass or jar.
Drop the seeds into the water. Some will float, others will sink over time.
Don't worry if they float at first — they often need a few hours to absorb water and sink.

3. Store in a dark, warm place

Place the glass somewhere dark, like a cupboard or closet.
Maintain a stable temperature between 20–25°C for best results.
Avoid direct sunlight or cold surfaces.

4. Wait and watch

Check the seeds after 12 hours.
If some seeds have sunk and begun to crack, they are ready to be transferred.
After 24 hours, move all seeds to the next stage—even if they haven’t cracked open yet.

What to do after soaking?

After soaking, it’s time to continue the germination process. Most growers use one of the following methods:

Option 1: Paper towel germination

Place seeds between two layers of damp (not wet) paper towel.
Put them inside a ziplock bag or between two plates.
Keep in a warm, dark area (22–25°C).
Check twice a day for signs of sprouting.
Once the taproot is 2–3 mm long, transplant to your growing medium.

Option 2: direct to medium

If your soaked seed has already sprouted in the water, you can place it directly into:

Soil
Coco coir
Jiffy pellets
Rockwool cubes

Plant it about 0.5–1 cm deep, root tip facing downward.

Common mistakes when soaking cannabis seeds

Soaking for too long

More than 32 hours in water can drown the seed. Seeds need oxygen to stay alive, even during soaking.

Using chlorinated tap water

Chlorine and other chemicals in untreated tap water can harm seed embryos. Always use filtered or rested tap water.

Cold water or cold room

If the water or room is too cold, the soaking process will stall. Seeds may take longer to sprout or fail altogether.

Not using clean equipment

Contaminated glasses, tweezers, or paper towels can introduce pathogens and lead to mold or seed rot.

Do all seeds need to be soaked?

No. Soaking is a helpful method, especially for:

Old seeds
Seeds with thick or hard shells
Unstable strains with inconsistent germination

However, fresh, high-quality seeds—like the ones you’ll find at Mavericks Genetics—often sprout quickly using only the paper towel method or by planting directly in moist soil.

Tips for boosting germination success

Keep seeds warm, but not hot (ideal range: 22–25°C).
Maintain constant humidity during the paper towel phase.
Label different strains during soaking to avoid confusion.
Handle seeds gently with sterile tweezers to avoid damaging the root.

Troubleshooting: Seed didn’t sprout after soaking

If your seed hasn’t germinated after 24 hours in water and 2–3 days in a moist paper towel:

Be patient — some seeds take longer (especially older ones).
Try scarification: lightly scratch the seed shell with sandpaper.
Try a hydrogen peroxide soak to soften the coat.
Try light pressure to crack the shell gently (last resort only).

Soaking seeds is simple — If you do it right

Soaking marijuana seeds is a proven, beginner-friendly way to kick off your grow. It boosts germination rates, shortens sprout time, and helps you identify which seeds are strong and viable. Just remember:

Soak for 12–24 hours
Never go over 32 hours
Move to paper towels or soil once hydrated

At Mavericks Genetics, we’re here to support you from seed to harvest. Whether you're starting your first grow or storing rare genetics, knowing how to germinate properly is the key to success.

Explore our full collection of premium cannabis seeds and start your next grow with confidence.