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How to Grow Weed: Germinating Cannabis Seeds

Germinating Cannabis Seeds


How to Grow Weed: Germinating Cannabis Seeds

Photo by Jorge Cervantes

How to Grow Weed: Germinating Cannabis Seeds

Jorge Cervantes shares his process for germinating cannabis seeds into healthy sprouts.

The gardening season is booming in North America, and it’s high time to start some tiny seeds that can grow into potent plants, says Jorge Cervantes, veteran marijuana cultivator and author of “The Cannabis Encyclopedia”.

1) Soak seeds overnight in a glass of plain water. They may float on the surface at first but should sink to the bottom in a few minutes. Make sure seeds get good and wet so that water penetrates the outer shell and growth is activated. Do not let seeds soak for more than 24 hours, or they might get too wet, suffer oxygen deprivation and subsequently rot.

2) Remove seeds from the water. Pour water out onto two paper (or cloth) towels on a dinner plate. Fold the towels over the seeds to cover them.

3) Drain the water from the dinner plate by tipping it to the side.

4) Place the seeds in a warm location (70°F–80°F; 21°C–27°C), making sure they are in darkness. Some gardeners go so far as to set the plate in a vertical position (so taproot grows downward). The seeds can also be set on a grate for drainage and air circulation.

5) Check moisture level of towels several times a day, watering once or twice to keep them evenly moist. DO NOT LET THE TOWELS DRY OUT! Let excess water drain away freely. The paper or cloth towels will retain enough moisture to germinate the seeds in a few days. Each seed contains an adequate food supply for germination. Prevent fungal attacks by watering with a mild 2 percent bleach or organic fungicide solution.

6) In a few days, seeds will sprout. Once the germinating cannabis seeds have sprouted and each seed’s white rootlet is visible, use tweezers to carefully pick up the fragile, germinated seeds and plant them. Do not wait for the white rootlets to grow more than 0.25 inches (1 cm) before planting, or growth could slow. Plant each germinated seed with the white root tip pointing downward. Take care not to expose the tender rootlet to prolonged light and air. Cover germinated seeds with 0.25 to 0.5 inches (1-2 cm) of fine, moist planting medium.

Photo Jorge Cervantes

Other Tips for Germinating Cannabis Seeds

Watering Issues

Over and under-watering are the biggest obstacles most gardeners face when germinating seeds and growing seedlings. Keep the soil uniformly moist but not waterlogged. Do not let the growing medium’s surface dry for long. Setting root cubes or planting flats on a grate allows good drainage.

A shallow flat or planter with a heat pad underneath may require daily watering, while a deep, 1-gallon (3.8 liter) pot will need watering every three days or more. A properly watered flat of rockwool cubes needs water every three to five days when sprouting seeds.

When the growing medium’s surface is dry (0.25 inches [1 cm] deep), it is time to water. Remember, there are few roots to absorb the water early in life and they are very delicate.

Hard Cases

Some seeds have a very hard outer shell (testa) and are difficult to germinate. Such testy cases can be softened or scarified to allow water to penetrate. To scarify, line a matchbox with a piece of fine-grain sandpaper or emery board. Put the seeds in the matchbox and shake for 10 to 15 seconds. Remove the seeds and make sure they have been scuffed a bit. Just a little scuffing will allow water to enter and set germination in motion.

1) Set seeds in a matchbox with an emery board or sandpaper on the bottom.

2) Close seeds inside the matchbox.

3) Shake matchbox for 10 to 15 seconds to scarify the seeds.

This is an excerpt from “The Cannabis Encyclopedia” by Jorge Cervantes, world-renowned indoor, outdoor and greenhouse cannabis cultivator. A veteran marijuana grower, Cervantes brings 30 years of experience traveling, studying and writing to bear in his best work to date. This was published in issue 19 of Cannabis Now’s print edition.

TELL US, have you tried Cervantes’ technique for germinating cannabis seeds?



  1. rebekah

    February 25, 2018 at 5:23 pm

    when is the best time to start them

  2. Jeff

    February 24, 2018 at 1:31 am

    Could you do an instructional on from seed germination to dwc hydroponics?

  3. Alice Marie

    June 21, 2016 at 3:08 pm

    Is there any THC content in the actual plants? I’m trying growing for the first time and if the plants don’t make it to a flowering stage I want to still try to use it for something

    • Artemis Rose

      November 13, 2016 at 6:30 am

      I dont think so. I think THC comes from the flower and before it becomes THC, it needs to be dried and cured and then heated. Im not sure if you can cook the plant though. Im also a newbie.

  4. Bill Myers

    May 30, 2016 at 2:32 pm

    No way to tell the sex of the plant from freshly germinated seeds I’m afraid. Most plants will show pre-flowers by 6 or 7 weeks but even then may not. Topping the plant then keeping the cutting under 12/12 lighting will force flowering and tell you what sex the mother plant is.

    Love Jorge Cervantes but that method of germinating is so old school and easy to mess up. Let the towel dry out once and they’re dead!

    I line a pill jar with 150 grit sandpaper and shake the seeds gently for a full minute, then plant pointy end up in small pots of finely screened ProMix about 1/2″/1cm deep and lightly cover with saran wrap. Keep surface moist but not soggy and make sure there is lots of light the minute the first sprout emerges. A 23W, 5000-6500K CFL is lots for a few seeds and the first week or two of growth. No danger of hurting young sprouts and the plants get established much faster if there is a bit of nutrients in the mix. Wetting the ProMix with a mild seaweed fertilizer works great as does the ProMix Veg and Herb blend cut 50/50 with regular ProMix.

    A 1mm mesh like mosquito screen is what I use to screen soil that I use to start seeds or cuttings to make sure there is good contact with the seed or stem surface.

    The seedling pictured above this article look like they didn’t have enough light when they sprouted and stretched more than they should tho that won’t matter later as the plant gets a few nodes of true leaves.

  5. Lewis Wood

    May 12, 2016 at 3:26 am

    Once seeds are terminated will it be easy too tell male from female?

    • Dylan

      August 3, 2017 at 9:00 am

      How can you tell?

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