Haworthias can be crossed among species and even hybridizations with other genera in the Aloeae tribe are possible. On the other hand, pollination can only be successful by crossing two individuals with different genes. Many growers consider breeding cultivars as the most fun part of growing Haworthias, which involves the search for new patterns, colors, shapes and textures.
Fine tweezers and a headband magnifier are useful tools for pollination. Tweezers should be sterilized before using.
Haworthia flowers on each stalk bloom bottom to top. When the upper parts of the petals curl outwards, a flower fully opens and its pollens are ready. The stigma will take 2~3 more days to mature, and when mature it will elongate and swell slightly. Generally, use pollen from a newly opened flower to pollinate the stigma of an older flower.
After identifying the male and female parent flowers, first carefully remove all petals of the male parent. This will expose its stamens and pistol. Repeat this for the female parent.
Then remove all stamens of the female parent. The stamens can be laid on a cloth or a paper for pollinating others later. Pluck 1~2 stamen from the male parent and rub the anthers to the stigma of the female parent, until some transferred pollen can be seen. During this process, be gentle not to break the stigma.
For a female parent flower, pollinating it for ~3 consecutive days often improves the chance of success. The best time for pollination is from noon to late afternoon. Keep the pollinated plants in a cool and shaded place to prevent pollens from drying out too quickly. After ~1 week, if the ovary becomes green and swollen, the pollination is successful.
The seed pod will keep growing for another 1~2 weeks. Once it matures, the pod snaps open to spill the seeds. To not lose the tiny black seeds of a Haworthia, when the color of the pod turns darker, loosely wrap it with a transparent sticky tape and leave some padding on the top. This allows the pod to breathe and will keep all the seeds inside it.