Plant-based sources of Vitamin B-12?
Vitamin B12 is stored in the liver and muscle of animals, and is also passed on to eggs and milk, so these are good sources for non-vegans. Humans produce B12 in the gut, but cannot absorb it. Many other animals produce it in the gut too, so unwashed plants that have been fertilized with animal feces may be a source of B12. However, there are many other reasons to wash your plants before eating them.

Some plants (spirulina, for example) has been touted as a plant-based B12 alternative but is inadequate for most people. As vegans, our best bet is synthesized B12. You can't synthesize it yourself, so no, you can't "grow" it at home, if that's what you mean. Where I live, vegan B12 is available both through the internet and in pharmacies, but I don't know the situation in your country.

The Vegan Society has useful information about B12, as does VeganHealth.org. The Vegan RD has a section about cyanocobalamin versus methylcobalamin if you want to dive into the details.