Best Way to Germinate Marijuana Seeds

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Written By Rocky Horton

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The cannabis plant is at its most delicate during the germination period, when it
transforms from a hard brown seed into a seedling with it’s first root and leaves. During this critical period, selecting the correct germination strategy, and keeping the seed at the proper moisture and temperature levels will ensure a speedy and successful transition from seed to seedling. This article will discuss several methods of germinating seeds, as well as the ideal humidity, temperature, and light parameters for germination.

What is Cannabis Seed Germination?

Germination is the process of “waking up” a dormant seed by providing it with the
environmental conditions that indicate it is time to grow into a plant. Indoors, this is done by mimicking the transition from winter to spring, when the soil warms and fills with water from melting snow and rain.

Once a viable marijuana seed is provided with the correct moisture and temperature
parameters, it will crack open and produce a small white taproot. After the taproot
forms, a stem will emerge from the opposite side of the seed and open into two small
round leaves, called cotyledons. These first leaves will only stay on the plant for a week or two before giving way to the first set of larger, serrated “true” leaves.

What Do Pot Seeds Need to Germinate?

The two most important considerations for germinating your cannabis seeds are
temperature and moisture levels. If these parameters are right, the pot seed will begin germination within 1-3 days. In comparison, seeds kept in less than ideal conditions can take up to two weeks to germinate, or fail to germinate at all.

For temperature, the seeds should be kept between 72-77 degrees Fahrenheit.
Temperatures on the upper end of this spectrum are preferred during the day, while the temp can be allowed to dip into the lower 70s at night. It’s a fine balance since seeds that are not kept warm enough will fail to germinate, but excessive heat may dry the seed out and damage the tap root.

During the germination period, the seeds should be kept in a high humidity environment. Ideally 60-80%. Seeds cannot, however, be left in soaking wet soil or standing water, as this will deprive them of oxygen. Ideally, the marijuana seed’s substrate will be misted a couple times per day, keeping it moist but not soggy.

During the early germination period, before the first leaves emerge, the seed does not
need to be exposed to light, and intense lighting can actually damage the fragile
seedling by burning it or drying it out.

How to Tell if Seeds are Any Good?

A healthy marijuana seed should be brown with a hard shell casing. Some minor
cracking or wrinkling on the seed is generally not an issue, but if the seed has a large
amount of damage, or feels soft or crumbly under your fingers, it will not germinate.
Similarly, seeds which are white or green should be avoided. These seeds are not fully
matured, and will produce a frail, small plant if they germinate at all.

To keep your seeds fresh, they should be stored in a cool, dark area where they will not be exposed to moisture, sunlight, or heat. Some growers like to refrigerate their seeds to preserve them and simulate winter conditions before germination.

Germinate Marijuana Seeds by Soaking in Water

The absolute easiest method for germinating weed seeds is to simply submerge them in water for 2-4 days. This process softens the hard outer shell of the seed, allowing the taproot to push through easily.

There is no need to move the seeds to a paper towel or cube to finish germinating. Once the taproot is .25-.5 inches long, plant the seed directly in soil. Contrary to popular belief, the seeds can be left submerged in water for up to 7 days without issues.

This method can be combined with the other steps to improve germination rates. Soaking is especially recommended for older seeds.

Germinate Cannabis Seeds with the Paper Towel Method

Paper Towel Method for Germinating Seeds
Seeds Germinated Using the Paper Towel Method

This is the most popular germination method for most home growers, especially beginners. The seeds are placed between two paper towels on a plate and misted twice daily for 2-3 days until the taproot emerges and grows to .25-.5 inches long. The seed is then very carefully moved into a potting medium, where it is placed with the taproot facing down.

Although watching the taproot grow can be reassuring to new growers, the paper towel method can be riskier overall than other methods discussed. At this early stage of development, the taproot is extremely fragile. The microfilaments on the taproot, which the seedling needs to take up water and nutrients, can get stuck in the paper towel and cause invisible damage to the root even if it looks unbroken.

Even with the risks, the paper towel method usually gives great germination rates so it’s especially good if you only have a few seeds and can’t risk losing any. You can also add a heating pad below the plate, but you’ll need to increase watering to avoid drying out.

Germinate Pot Seeds Using Starter Cubes or Pellets

My favorite way to germinate cannabis seeds is by planting them in a starter cube such as Riot Rooter cubes or Jiffy Pellets. These plugs have a nutrient profile and density that is ideal for seeds, increasing your chances of fast and healthy germination. Rock wool cubes are also popular among some growers.

To start, make a small hole in the plug and insert the seed. If there’s already a hole, you’ll probably want to make it a little bigger with a pen, etc. You can dip the plug in water or simply mist well before popping the seed. Tear off a piece of the cube and plug the hole.

Water with a spray bottle once the top of the cube is dry. Usually 1-2 times daily. In order to keep the seed from drying out between waterings, consider using a humidity dome.

A heating pad can also be added underneath your germination tray to keep the soil
warm. If the seeds are not kept warm enough (mid 70s Fahrenheit) they will germinate slowly or not at all.

Germinate Weed Seeds in Soil

Starting Weed in Solo Cups
Starting Weed in Solo Cups

If you don’t want to worry about transplanting your seedling after germination, the seed can be started directly in soil. If you select this method, be sure to select a potting soil with an appropriate density and nutritional profile for seeds.

Standard potting soil may be too dense for seedlings, resulting in suffocation. It’s also more easy for this type of soil to be overwatered, which also results in oxygen deprivation.

Soil that is fortified with too many nutrients can damage fragile seeds. Make sure the nutrient profile of your soil is appropriate for seedlings.

Once you select a soil medium, the marijuana seed can be planted and cared for similarly to those planted in a starter cube. You won’t need to water as often when planting directly in soil. If using solo cups, I usually wait 5 days between the first couple waterings.

How to Plant Cannabis Seeds

The seed should be planted about .25 to 1 inch deep in either a starter cube or soil,
depending on your chosen method. The plant’s taproot will emerge from the pointy end of the seed. Planting the seed with the pointy end up is ideal since the taproot makes a u-turn after coming out. The seed will still germinate regardless of the orientation though so it’s not necessary.

If the taproot has already emerged either via the paper towel method or soaking, just make a hole an inch or so deep and drop the taproot in first.

Water when the top 1 inch of soil is obviously dry to the touch. If unsure, wait. Solo cups need about 5 days between the first couple waterings and 3 gallon fabric pots need about 5-6 days. Gradually decrease the days in between waterings as the seedling grows.

The seedling will not need light until its first leaves emerge, after which it can be put under LEDs at 25% intensity.


After inspecting your seed to ensure that it is firm and brown, it is time to plant. Plugs
designed for seedlings, such as rapid rooter cubes or jiffy pellets are great choices, but the paper towel method is the most popular.

You chances of germination can be increased by using humidity domes and a heating pad to keep the growing medium moist and warm.

The seeds will not need any light while germinating, but should be placed under LED lights dimmed to 25% after sprouting.

If your marijuana seed is provided with ideal conditions, its taproot should emerge within one to three days, with the first leaves following a few days after that.

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Rocky Horton


Rocky Horton is an experienced cannabis grower and the founder of IndoGrow. The IndoGrow editorial team has over four decades of combined growing experience. Learn more.