Fem seeds are made from hermed female pollen, which passes on the herm traits to the seeds...
Here is what seed man says
SEEDSMAN CANNABIS STRAINS 1 1
In Greek mythology, Hermaphroditus, the son of Hermes and Aphrodite was fused with a nymph, Salmacis, resulting in one individual possessing physical traits of both sexes.
Hermaphroditism is a natural trait that occurs spontaneously in cannabis plants in the wild as a final emergency response to the absence of either sex in a colony. The mechanism allows the plant to self-pollinate by producing both female and male flowers. Most dioecious (distinctively male or female) plants have apparently evolved from hermaphroditic ancestors, so the trait remains partly active in many species of plants. Although this trait prevails in many pure sativa lines, it has been largely outbred from modern commercial hybrids. Usually it’s the female plants that produce staminate parts although reversal of both sexes has been reported by growers. Seemingly normal dioecious individuals can display this trait when they are grown in unfavorable environmental conditions. Some examples of things that might affect the sex of cannabis plants include high and low temperatures, ph fluctuations, plant hormones, light leaks in the grow room, water related stress and overfertilsation. In this sense there are no true males or females, only dioecious individuals with a greater or lesser potential for the dual-sex state.
Female plants will most likely turn if they are genetically prone to the condition. Once turned, the females will form modified or incomplete pollen sacks that look like tiny bananas. The change often goes unnoticed because the bananas start growing right out of the bud and they are difficult to spot with the naked eye. The pollen from these hermaphroditic females can either be fertile or sterile. If the pollen is fertile, she usually ends up pollinating all the plants in the grow room, effectively ruining the entire sensimillia crop. Plant stability is measured by how much stress they can handle and highly stable female plants will not turn into hermaphrodites no matter how much environmental stress you subject them to. These are the females that we are looking for when we want to make feminised seeds.
Generally speaking, hermaphroditism is considered an unwanted trait in drug strain cannabis plants. The trait is dominant in its expression, which means that any parent carrying this trait will pass it on to its offspring. There are however some uses for this trait, which include making feminised seeds. By removing the Y chromosome from the equation, we are left with nothing but female offspring. The reason why these seeds exist in the first place is because they remove the need to sex the plants before flowering them, which can save growers a lot of time and trouble. Unwanted male plants take up much needed space in the grow room and female clones need a lot of care. Feminised seeds eliminate those problems because they will produce female plants 99% of the time (the remaining percentage makes room for spontaneous genetic anomalies).
The main concern with making feminised seeds is that in order to create them, we have to allow a hermaphroditic female to pollinate itself or another female plant in order for the offspring to carry only female genes. This is problematic because we don’t want the offspring to become hermaphroditic as well. The females that are easily pushed towards hermaphroditism are usually removed from the grow room before they have the chance to pollinate themselves and other females. Seeds from these plants are usually highly unstable and produce one generation after the other of mostly hermaphrodites. Not exactly what we are looking for. So only the most stable and tolerant plants will be eligible for making female seeds. What we are looking for is only the slightest expression of this trait, anything else would defeat the purpose of what we are trying to do. By using only relatively stable females for our feminised cross, we decrease the chance of getting hermaphrodites further down the line. After all, what we want is a constant supply of normal and stable female plants suitable for indoor cropping, not a bunch of hermaphrodites pollinating each other all over the place.
We start by manipulating the environment in order to find the plants that can handle the greatest degree of stress without any significant adverse effects. The more they can handle the better. This screening process is crucial for creating stable female seeds. Using two plants, one normal and one hermaphroditic female will give us the best result because we get recombination of genes from both the female parents, while self-pollination is basically inbreeding. Self-pollination is sometimes used to isolate traits in rare female clones that would otherwise be lost but it might also give rise to genetic depression, mutations and all sorts of physical disorders. In both cases the offspring will carry only female genes but the seeds from the selfed female would be genetically less diverse and might result in fewer healthy individuals. Naturally the normal female used in our cross would also have to be stress-tested and proven stable for good results. Once we have found a strong female candidate, we can start making feminised seeds. We need a catalyst to start the process and silver water is usually administered to the female plants at this point. The stress from the tiny but toxic silver particles is just too much for the female to handle, so she responds by reverting to the dual-sex state and starts producing male flowers.
There is also another method for creating feminised seeds called rhodelisation, which was developed by the breeder Soma. Rhodelisation means that you allow a female plant to flower for an unnaturally long period of time in order for it to produce a few male flowers. Remaining unfertilised late in the season constitutes a problem for the female plant so she tries to self-pollinate in order to preserve her genes. This method is substantially more time consuming but it provides a natural way of producing feminised seeds without subjecting the plants to extreme levels of stress. It is however not an alternative if time is a factor and that is usually the case. This method takes about twice as long to complete, depending on the flowering cycle of the strain that is feminised.
High quality commercial seeds from feminised plants should therefore in theory give rise to mostly normal females that are resistant to the hermaphroditic condition. This is what we can hope for but it’s not always the case. Different breeders use different methods but usually there won’t be any problems if the plant is grown in near optimal conditions. Stress is the trigger that launches the hermaphroditic trait so there is always a degree of caution involved when growing these plants. Keeping a close eye on them is essential. On the positive side, feminised plants are a breath of fresh air because the problem of identifying females and hoping for as many as possible is eliminated. If 10 female seeds are planted, 10 female plants will grow
