The paper towel method starts cannabis seeds between two damp paper towels in a warm, dark place. Seeds crack and show a taproot in 2 to 7 days. Plant the seed when the root is 1 to 2 cm (0.4 to 0.8 in) long.

The Best Way to Germinate Cannabis Seeds

What you need

  • Seeds, dry and stored in a cool place
  • Two paper towels, white and unprinted
  • A plate or a sealable plastic bag
  • Water at room temperature
  • Tweezers for the seed shell
  • A thermometer for the plate area

Steps

  1. Fold one paper towel in half and set it on a plate.
  2. Wet the towel and squeeze out the extra water. The towel should be damp, not dripping.
  3. Place the seeds on the towel, 2 cm apart.
  4. Cover with the second towel. Wet it and squeeze it out the same way.
  5. Set the plate in a dark spot at 21 to 26 C (70 to 80 F). A closed bag holds moisture.
  6. Open the towel once a day. Add water in small drops if the towel dries.

Temperature and moisture

Germination runs fast at 22 to 25 C. Root growth slows below 18 C (65 F). Water is the main risk. A towel that sits in standing water cuts oxygen to the seed and mold follows. A towel that dries stops the process. Target a towel that feels damp and leaves no water on the plate.

Cannabis Germination Guide for Beginners

Timeline

  • Day 1 to 3: the shell splits and a white root tip shows.
  • Day 3 to 7: the taproot reaches 1 to 2 cm.
  • Day 7 to 10: older seed or cool room slows the start. Check the towel for mold.

Seeds that show no crack after 10 days at the right temperature are unlikely to sprout.

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Planting the seed

Fill a small pot with a light soil mix and water it. Make a hole 1 to 1.5 cm deep. Set the seed with the root tip down. Cover it and keep the mix moist. Do not pack the soil. Cotyledons open in 1 to 3 days under light. Light is not needed for the paper towel stage.

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Common errors

  • Soaking the towel until water pools on the plate.
  • Leaving the plate in direct sun or on a cold floor.
  • Touching the taproot. Handle the seed shell with tweezers instead.
  • Waiting too long. Roots that reach 3 cm tangle in the towel fibers.
  • Using water with a high mineral load. Filtered water at pH 6 to 7 works.

Legal note

Rules on cannabis seed germination differ by state and country. Check local law before you start a seed.