Feminized cannabis seeds are seeds bred to produce female plants. Because the female plant grows the flower that carries cannabinoids and terpenes, growers buy feminized seeds to avoid the male plants that pollinate a crop and turn buds seedy. A well-made batch of feminized seeds sprouts into roughly 95 to 99 percent female plants, though stress during the grow can still push a female plant to show male traits.

How feminized seeds are made

Regular breeding needs a male plant to supply pollen. Feminized seed production removes the male from the process. A producer treats a female plant with a chemical such as silver thiosulfate or colloidal silver. Silver blocks ethylene, a hormone the plant uses to build female flowers, so the treated plant grows male flowers instead. Those flowers release pollen that carries only female genetics. When that pollen lands on another female plant, the resulting seed holds two X chromosomes. There is no Y chromosome to pass on, so the seed grows into a female plant.

Feminized vs. regular vs. autoflowering seeds

Before you germinate: what you need

How to germinate feminized cannabis seeds

  1. Fill a small glass jar with room-temperature water and drop the seeds in.
  2. Set the jar in a warm, dark place for 12 to 24 hours.
  3. Tap the jar once after 8 hours to push any floating seeds under the surface.
  4. Slide the seeds onto a damp paper towel and fold the towel over them.
  5. Place the folded towel inside a ziplock bag and leave the bag open a crack for airflow.
  6. Keep the bag warm and out of direct light.
  7. Check the seeds each day. A white taproot should appear within 24 to 72 hours.
  8. Move the sprouted seed into your medium with the taproot pointing down, about half an inch deep.
  9. Keep the medium moist and hold the light on an 18 hours on, 6 hours off schedule until the seedling opens its first leaves.

How to keep plants female through flower

Feminized seeds carry female genetics, but a plant can still grow male flowers if it gets stressed. Common triggers include light leaks during the dark period, heat above 85 degrees Fahrenheit, nutrient swings, and root damage from rough transplanting. Check each plant at the base of the stem near lower nodes twice a week during the first three weeks of flower. Remove any plant that shows pollen sacs before the sacs open, or the whole room can seed.

Storing feminized seeds

Seed viability drops with heat, moisture, and light. Keep seeds in an airtight container with a desiccant pack, store the container in a dark drawer or the door of a refrigerator, and let it reach room temperature before opening it. Seeds kept this way often stay viable for two to four years, and some keep far longer.

Common mistakes