# Feminised seed

> Feminised seed is seed made by pollinating a female with pollen from another female (or itself) that was chemically reversed, so nearly every seed grows into a female.

- Canonical: https://genetixbay.com/knowledge/glossary/feminised-seed.html
- Also written: feminized seed, feminised seeds, feminized seeds, feminised, feminized
- Glossary category: Genetics and breeding · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

Feminised seed is produced by crossing two females, or a female with herself. One of them is treated so that it grows [male flowers](https://genetixbay.com/knowledge/glossary/staminate-flower.md) and makes pollen ([sex reversal](https://genetixbay.com/knowledge/glossary/sex-reversal.md)), most often with [silver thiosulfate](https://genetixbay.com/knowledge/glossary/sts.md) (Ram and Sett 1982; Lubell and Brand 2018). Because that pollen carries only X [chromosomes](https://genetixbay.com/knowledge/glossary/chromosome.md), the seed is genetically female (XX).

## In practice

Feminised seed saves space and time: no males to find and remove, nearly every plant flowers into usable bud. That is why most seed sold for home growers is feminised.

Its quality depends entirely on the breeder's discipline. Good practice is to reverse only females that have stayed fully female over several runs, under controlled conditions, and to grow out and check the seed before release. Poor practice (reversing a plant that already [herms](https://genetixbay.com/knowledge/glossary/hermaphrodite.md), or using pollen from stress herms) spreads unstable sex expression into the seed.

Feminised seed cannot be used to select males, so lines bred only by feminising lose half of what breeding normally samples.

## Don't confuse with

- **S1**: feminised seed from a female [selfed](https://genetixbay.com/knowledge/glossary/selfing.md) with her own reversed pollen. All [S1s](https://genetixbay.com/knowledge/glossary/s1.md) are feminised; most feminised seed is a cross of two different females.
- **Regular seed**: male × female, about half males.
- **Autoflower**: a flowering trait, independent of feminisation.

## Myth check

Herms in feminised seed are mainly breeder error, not "what fem seed does". See [feminised seed and sex reversal](https://genetixbay.com/knowledge/breeding/feminised-seed-sex-reversal.md) and [Mythbusters](https://genetixbay.com/knowledge/mythbusters.md).

## Related terms

[Regular seed](https://genetixbay.com/knowledge/glossary/regular-seed.md), [Sex reversal](https://genetixbay.com/knowledge/glossary/sex-reversal.md), [STS](https://genetixbay.com/knowledge/glossary/sts.md), [S1](https://genetixbay.com/knowledge/glossary/s1.md), [XY sex determination](https://genetixbay.com/knowledge/glossary/xy-sex-determination.md)

## Read more

- [Feminised seed and sex reversal: methods, with safety notes](https://genetixbay.com/knowledge/breeding/feminised-seed-sex-reversal.md)
- [Regular, feminised, autoflower or clone: choosing your starting material](https://genetixbay.com/knowledge/basics/seed-types-regular-feminised-auto-clone.md)

## Sources

1. Ram HYM, Sett R. 1982. Induction of fertile male flowers in genetically female Cannabis sativa plants by silver nitrate and silver thiosulphate anionic complex. Theoretical and Applied Genetics 62:369-375. https://doi.org/10.1007/BF00275107
2. Lubell JD, Brand MH. 2018. Foliar sprays of silver thiosulfate produce male flowers on female hemp plants. HortTechnology 28(6):743-747. https://doi.org/10.21273/HORTTECH04188-18
3. Flajšman M, Slapnik M, Murovec J. 2021. Production of feminized seeds of high CBD Cannabis sativa L. by manipulation of sex expression and its application to breeding. Frontiers in Plant Science 12:718092. https://doi.org/10.3389/fpls.2021.718092