How to germinate Cannabis seeds: a guide for beginners

Last updated in February 2024

In this guide, you’ll learn step by step how to germinate with the paper towel method, as it requires simple equipment and has a high rate of germination. How to germinate marijuana seeds indoors step by step, what you need to start, how to store your seeds, and tips to get your seeds started!

This is how the life of the Cannabis plant begins. A viable Cannabis seed looks brown with some stripes, hard to the touch, and dry. If it feels weak or it’s white or light green, it’s probably an undeveloped seed and it won’t produce a healthy plant.

You can start your seeds indoors or outdoors, but we recommend doing it indoors because there’s a bigger chance of seed survival. When germinating seeds outdoors, the small plants are exposed to cold/hot weather, wind, pests, and mold. In this stage, plants are very vulnerable and it’s important to keep them safe. On the contrary, when germinating seeds indoors, we reduce or eliminate the possible negative outcomes caused by temperature changes and insects, for example.

There exist many methods for germinating seeds indoors. For example, placing your seed between cotton balls or paper towels sprayed with water, placing your seed in a jiffy or a small cup directly into the soil.

How to germinate Cannabis seeds in 3 easy steps

For starting seeds indoors you need:

• Cannabis Seeds
• Plastic container with a lid or 2 plates
• Paper towels
• Water sprayer with clean water
• Small cup or glass of water

Time: From 12 hours to 7 days

How to germinate Cannabis seeds – Paper towel germination method step by step.
For germinating, Cannabis seeds need high relative humidity, air, and water

1. Place the seed on a paper towel and inside a container, spray with room temperature water

Place your Cannabis seeds on a paper towel, inside a plastic container, or between two plates. This container must remain dark, warm, and humid at all times. Spray the napkin with warm water and cover it with a lid or plate. Place your container in a warm place and leave it there.

2. Open the container every few hours and spray with water until the seed opens
Open the container every few hours and spray it with water. Never let the napkins dry up or your seed won’t sprout. The napkin must stay moist, but not soaking wet. Prepare the next growing medium as soon as you see the seed opening.

3. When the seed opens and shows a tap root, plant it in a small cup, jiffy, or plug
When the seed opens up and starts showing the first white tap root, it’s time to put it in its next growing medium (soil, coco, peat) in a small cup, jiffy, or plug.

Start your germinated seeds in a small container to avoid watering issues

TIPS before starting to germinate Marijuana seeds:

• Store your seeds in a sealed plastic bag in the fridge and take them out when you decide to plant them. This mimics the season change from Winter to Spring when Cannabis plants usually sprout and promote germination.
• Soak your seeds in a glass of clean water, at room temperature (20°- 25° C) for 12 hours. Keep in a warm place and signal it to prevent accidents (like drinking the water or throwing them out).
• Soaking your seeds in a glass of water for more than 24 hours will deprive them of oxygen and they are likely to drown and may not sprout. A seed that sinks after 12 hours it’s likely to be viable and good for germination. If it floats, touch it, and it will probably sink. On the other hand, seeds that float after 12 hours are not likely to sprout soon.
• Get a water sprayer and set reminders to spray your germinating seeds. A dry napkin may also damage a recently sprouted tap root and kill off your plants before starting.
• It is very important to track germination dates and stage changes during your grow. Do not forget about your germinating seeds! If you leave them for too long in the container and do not plant them, they’ll grow a long taproot but they’ll end up dying without proper growing conditions. Set reminders and schedule your tasks. Use our free app Grow with Jane to make it easy and fun!

Frequently Asked Questions about Cannabis Germination

What is the best temperature and humidity for Cannabis germination?

The best temperature to germinate Cannabis seeds is 25° C / 77°F
The best relative Humidity to germinate Cannabis seeds is 70 / 90%  

Do I need growing lights for Cannabis germination?

No! You can start the germination process and you won’t need any lights yet, but it’s recommended not to wait too long to get them because you’ll need them soon!
The Cannabis plant needs light as soon as it pops out from the soil. In the first weeks, young plants are not yet able to process high-intensity light. Led lights or lower-wattage lights as CFL are better for this stage. A cold (blue) spectrum light is better for this stage, as it promotes vegetative growth.

A Cannabis seed just sprouted but the seed shell is stuck on the seedling. What should I do?

The seed shell normally falls off when the first pair of round leaves (cotyledons) are formed. Sometimes, this shell is tough and gets attached to the already-formed cotyledons. You can spray it with clean water to soften the shell and leave it for a few more hours. If you decide to take it off, you can try spraying it a little with water and gently take the shell off using sterilized tweezers. Be very careful not to damage the seedling!
Notice that in the following pics, the seedling finally manages to get rid of the seed shell by spraying water on it, but the soil mix seems muddy and not of good quality. Overwatering may cause stunted growth in seedlings!

When is the best time of the year to germinate Cannabis seeds?

The best time to germinate a Cannabis seed for outdoor grow is at the beginning of Spring. Cannabis plants are annual, they grow all Spring and Summer and start flowering towards Autumn when days grow shorter. Growing indoors, you may germinate your seeds whenever you like if you manage to give them the right environment to live in. Read our Growing Checklist to find out how to do it!

How long does it take for a Cannabis seed to germinate?

A Cannabis seed may take 12 – 72 hours (best conditions) to a few days to germinate, or even more if the environmental conditions are bad. Storing your Cannabis seeds properly and giving them the best environmental conditions to germinate will increase the chances of success.

My Cannabis seeds won’t sprout after a few days, why?

Sometimes seeds won’t sprout for many reasons: they are old or dry, have wrong storage conditions, wrong germinating methods, problems at the seed bank, etc.
I do not recommend disturbing or trying to crack the seeds, as they are very fragile at this stage and you may damage them. Try the above-mentioned “glass of water” method to “activate” your seed. It’s better to be patient right now, make sure they have the above-mentioned sprouting conditions, and wait.

How to store Cannabis seeds

Keep your seeds in a dry, dark, and cold place, for example, in the fridge (in the original packaging if possible), inside a ziplock plastic bag for better conservation. When the time of germination comes, get your seed out at ambient temperature.

Germinating is the first step towards your next Cannabis plant!

If you’ve read the whole article, now you know the basics of how to start growing your own Cannabis plant. Patience is key to success when growing Cannabis and this stage is no exception. Taking notes is a very good method to track your progress and see what’s working and what’s not.

Remember to keep your seeds in the fridge until you’ve got everything ready to start and follow the steps closely.

Growing Cannabis requires a bit of reading and experimenting, but it’s not rocket science and it’s a VERY rewarding experience. We hope you feel encouraged and start germinating your Cannabis seeds soon!

Tell us in the comments if you tried this method and how it’s going!

Read the following articles and become a Cannabis home grower!

Checklist: What do I need to start growing Cannabis? Pics + Tips [2021]

Cannabis seedlings – How to avoid stunted growth

The Cannabis plant life cycle – Cannabis stages week by week