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Growing Cannabis Seeds: Here’s Everything You Need To Know

Growing cannabis seeds can be incredibly rewarding. Our step-by-step guide has all the info you need, from seed selection to storage.
Growing Cannabis Seeds

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Starting cannabis from seed can be extremely rewarding. Not only do you get to take your plants through a complete growth cycle, but you might also get to produce some seeds of your own. With seeds, anyone can go from a cannabis enthusiast to an amateur breeder. You’ll be able to custom tailor your plants to meet your specific needs or possibly develop a new strain or two. To help you experience the wonders of seeds, we’ve created the Seeds 101 series. This ultimate guide to growing cannabis seeds summarizes the series and tells you where to find more information.

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1. How to find and choose the right seeds

How to find and choose the right seeds

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If you’re growing from a clone, it’s unlikely that your plant will produce seeds. Seeds develop after a male cannabis plant pollinates a female. Only female plants produce seeds. Yet, when you smoke cannabis, you’re typically smoking the unfertilized bud of the female flower. This can make it a bit difficult to actually find seeds if you’re interested in growing from scratch.

There are a couple of ways you can source your seeds. If you live in a legal medical or recreational state, ask your favorite dispensary for reputable local seed companies. Many people also order seeds from online seed banks. Though, this is illegal in the United States. Seeds for “souvenir purposes” are legal in many regions around the world, allowing many seedbanks to ship worldwide.

Though ordering seeds is illegal in the U.S. and you can face criminal charges, seed arrests are uncommon in comparison to arrests from growing or germinating plants. It’s not uncommon, however, to have your mail-ordered seeds confiscated by U.S. customs. If you order seeds from an international seed bank and they are found, you will get a letter in the mail saying that your seeds have been tossed out.

Finding seeds may be a little tricky, but choosing the right seeds to grow is easy. There are a few qualities that set good seeds apart. When you’re picking out your seeds, watch for these features:

  • Color: Look for a dark brown teardrop-shaped seed. Some seeds have dark stripes or splotches of different brown, black, or tan shades. Avoid pale or green seeds.
  • Size: Indicas produce larger seeds with striping. Sativa seeds are a smaller and more uniform in color.
  • Hardness: A good seed has a hard outer shell. Don’t pick seeds that are soft or damaged.

2. How to germinate and sprout your seeds

In many places, cannabis becomes illegal once seeds begin to germinate. Germination is simply the process of getting your sprouting your seed to grow a plant. If you are able to safely germinate your seeds, there are a few ways to go about the process. Almost every grower has their preferred germination method, but here is a brief summary of the most popular techniques:

Pre-soak method

cannabis seeds soak

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Basically, pre-soaking means that you soak your seed in warm (not too hot!) water until they sink to the bottom of your glass or container. The idea is that soaking your seeds speeds up the germination process by making sure that your seed is completely moist before planting.

Some people soak their seeds for up to seven days, or until a root appears. Though, the major concern here is that pre-soaking increases the risk of rot and mold before you’ve even fully started your plant.

Paper towel method

The paper towel method is one of the most popular germination methods out there. It takes a little longer than the pre-soak method, but there’s less of a risk of rot if you’re observant. You simply moisten a paper towel, fold it, place the seeds inside the fold, and then place the damp towel into a plastic baggie.

Keep the plastic baggie in a dark, warm place, but keep an eye on it so that it doesn’t mold. After a couple of days, a root will appear. You can then transfer the germinating seed into soil.

Direct soil method

Direct soil method to grow cannabis seeds

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You can plop your seed directly into soil whether or not you’ve pre-moisten it in any way. Have a small container of prepared soil ready. Make a tiny, half-inch well in the soil. If you’ve pre-soaked your seeds, place the seed root-end down. If you’re starting with dry seed, place it pointed end down. Flick a tiny amount of soil back over the seed. Then moisten the soil with a sprayer or small amount of water.

If you started from a dry seed, cover the container with plastic wrap to create a greenhouse effect. Store your newly planted seed in a warm, dark place. After about 4 to 5 days, your seeds will sprout. At this point, move your seeds to a brighter, well-ventilated location and wait for them to get large enough to transplant.

3. How to sex your sprouts

When your little plants reach about the 6-week mark, you’ll be able to tell their sex. If you’ve started from feminized seed, you won’t need to worry about this step. Feminized seeds only produce female cannabis plants, making them great options for folks who plant to just grow from clone after their initial start with seeds.

If you’re not growing from feminized seed, sexing your plants is one of the most important parts of the early growing process. In order to get a good harvest of usable cannabis flower, you’ll need to separate your male and female plants. If you do not separate your plants, you risk unwanted pollination.

When female plants are pollinated, they stop spending energy on developing potent buds. Rather, they spend energy developing seeds. Here’s a brief summary of what to look out for.


Cannabis sprouts will produce “preflowers”. These preflowers will be found in the crux between the main stalk and the branch. A sure-fire way to tell that your plant is female is to look for preflowers with long, white hairs. These white hairs are pistillate hairs, part of the female sex organ of the plant.


Male plants develop flowers, too. However, male flowers are markedly different than female flowers. While females produce a conical bud covered in long white hairs, male flowers look more like little bundles of downward facing tulip. These little bundles are pollen sacks. To spot a male, look for a small bud in the crux between a branch and the main stalk. This bud will be bulbous without any hairs.

4. How to produce your own seeds

There are a lot of reasons to hang on to male cannabis plants. The best reason? You can use them to create your own seeds. You can either pollinate an entire female cannabis plant for a TON of seeds, or you can pollinate select branches to save some of your harvest and still have some seeds for next year.

Pollinating an entire plant is simple: take a female plant and place it next to a mature male plant. Give the male plant a good shake to release the pollen. You can rotate your female plant around a few times and shake again to make sure all areas of the plant have been exposed to pollen.

A better option is selective pollination. Pick out your favorite female plant and your favorite male plant. Keep the plants separate. Clip a couple of good flowers off your male plant and put them into a long, paper wine bag. Take the wine bag over to you female plant.

Carefully slip the bag with clippings over a low flower on your female plant. Using tape, a zip tie, or some string, secure the bottom of the bag around the branch. You’ll want to make the enclosure fairly tight to avoid pollinating other flowers on the female plant.

Once the bag is secure, give it a good shake. This will release the pollen and sprinkle a nice coating of pollen over the female flower. Leave the bag on for a couple of hours, and then carefully remove.

Selective pollination means that save the rest of your female flowers for consumption. Pollinating an entire plant wastes potentially good, smokable flower. Once you’ve pollinated your plants, expect seeds 4 to 6 weeks.

5. Preserving and storing your seeds

After you have found your seeds, germinated your plants, gone through the growth cycle, and cultivated your own seeds, you better know how to store them right. Cannabis seeds can last for years when kept in the right conditions. This means that if you’ve found a strain pairing that you really love, you can come back to it time and time again. For the most part, always remember these three rules:

  • Don’t keep your seeds in direct sunlight. Find somewhere dark
  • Keep them away from moisture. Store them somewhere dry
  • Pay attention to temperature. Pick a cool place

There are a couple of common seed storage methods out there, and each one has its pros and cons. Here is a brief summary of popular techniques:


Some folks have been able to successfully germinate seeds after storing them for 10 years in a refrigerator. Though, this method is debated among growers and breeders out there. If you open and close your fridge a lot, the seed will be subjected to sudden temperature changes. You also risk exposing your seeds to excess moisture, allowing them to rot.

To protect against these concerns, keep your seeds in an opaque airtight container. Throw in a food-grade desiccant pouch to suck up any moisture. Vacuum sealing your seeds with desiccant also works well.


Freezing is another seed-saving technique that sparks debate. When you freeze seeds, some of the cells will rupture because of the bitter cold. You also risk drying the seeds out the longer they’re kept in such intense temperatures. However, some folks swear by the freezer method.

If you want to try some freezer seeds, keep them in a vacuum sealed container with a food-grade desiccant. Make sure they aren’t exposed to too much light or drastic swings in temperature.

With both the freezing and refrigeration methods, make sure you warm your seeds to room temperature before trying to germinate them. Just let them sit out for a bit in a dark container. You don’t want to shock the seeds with sudden temperature changes.

Growing from seed is a beautiful thing. Taking your plant from seed to sprout to full-bloom is a miraculous and therapeutic experience. Growing great cannabis takes a bit of forethought and preparation, however. It’s best to do your research ahead of time and plan out what approach you’re going to take with your plants.

To continue your education from growing cannabis seeds and check out our How To Grow Marijuana and Super Soil series. You’ll learn something, we promise.

Do you have any go-to tips for growing cannabis seeds? Share them with us on social media or in the comments below. We’d love to hear from you!

August 12, 2019 — Last Updated June 15, 2020
Written by Anna Wilcox

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August 12, 2019 — Last Updated June 15, 2020
Written by Anna Wilcox

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