Fold cannabis seeds inside two damp paper towels, seal them in a bag or between two plates, and keep them dark at 70 to 80°F. Check every 12 hours. Most viable seeds split and push out a white taproot in 2 to 5 days. Plant the seed in soil or a starter plug as soon as the taproot reaches about 1/4 inch, before it grows into the towel fibers.
What you need
- Seeds, dry and firm, no cracks or crushed shells
- Two plain white paper towels, unbleached and unscented
- Clean water at room temperature
- A zip bag, two plates, or a shallow container with a lid
- A thermometer for the germination spot
- Tweezers or a clean spoon for moving the sprouted seed
Steps
- Wash your hands and wipe the work surface, since clean handling limits mold on the towel.
- Fold one paper towel in half twice to make a pad about the size of your palm.
- Wet the pad under the tap and squeeze it until no water drips out. It should feel damp, not soaked.
- Set the pad on one plate or on the open half of the zip bag.
- Lay the seeds on the pad at least 1 inch apart so roots do not tangle.
- Cover the seeds with a second damp pad and press down gently so the towel touches each seed.
- Slide the stack into the bag and leave the seal open a finger width, or cover the plate with a lid set slightly ajar, so air moves.
- Put the container in a dark cupboard or drawer and keep it at 70 to 80°F. A heat mat on low works if the room runs cold.
- Open the towel every 12 hours to look for a white tip and to confirm the towel is still damp.
- Mist the towel with water if it dries, then squeeze out any excess before you close the container again.
- Move the seed to soil when the taproot is 1/4 to 1/2 inch long.
- Plant with the taproot pointing down, cover with 1/4 inch of soil, and water once.
The wetness test
Excess water is the most common cause of failure. A towel that drips when you tilt the plate cuts the oxygen the seed needs to break dormancy. Squeeze the pad in your fist before use, and if a puddle forms under the seed, pour it out and wring the towel again. Aim for a towel that is damp to the touch with no standing water anywhere in the container.
Cannabis Seed Germination: Soil vs Water
Temperature and timing
Seeds sitting below 65°F germinate slowly and unevenly, and the extra days in a wet towel raise the risk of rot. Above 85°F the seed uses energy faster than the root can establish. Hold the container near 75°F for steady results. Expect the shell to crack in 24 to 72 hours and a visible taproot by day 3 to 5. Older seeds can take up to 10 days.
Troubleshooting
No taproot after 7 days
Check the towel for dryness and the temperature of the spot. Move the container somewhere warmer and give the seed another 3 days before you discard it.
cannabis germination problems solutions
Seed turned soft or fuzzy
Discard it and the towel. Mold means too much water or too little airflow. Start the next seeds with a drier pad and a wider vent.
Taproot grew into the towel
Cut the towel around the root instead of pulling. Plant the seed with the scrap of towel attached and let it break down in the soil.
Shell stuck after planting
Keep the surface moist and the humidity dome on for 24 hours. Do not pry the shell off by hand while the seedling is still pale.